Harvard Health A-Z

Arthritis: Keeping Your Joints Healthy

There are more than 100 different types of arthritis, but all have one thing in common: These different diseases affect joints. Many of them also affect the areas and structures surrounding joints. Perhaps more important, arthritis is painful and can interfere with your ability to do the things that you enjoy, from cooking a meal to playing golf.

The number of people with arthritis is staggering. In 2005, 66 million adults in the United States ? nearly 1 in 3 ? had either been diagnosed with arthritis or were living with undiagnosed chronic joint pain and other symptoms. Although the risk of some types of arthritis, such as osteoarthritis, increases with age, more than half of those affected by all types of arthritis are younger than 65. In fact, arthritis is the leading cause of disability in Americans older than 15.

It doesn't have to be that way. If you have arthritis, there are steps you can take, starting today, to protect your joints, reduce pain, and improve mobility. The exact strategy depends on the type of arthritis you have, but for most people, there is reason for optimism.

This report describes how arthritis affects the joints and other structures. It explains how the various kinds of arthritis are diagnosed and treated, and tells how to minimize the impact of arthritis in your life.

Obtaining the correct diagnosis is particularly important ? and sometimes quite difficult. Joint discomfort can result from any one of a number of different conditions, but even blood and imaging tests rarely provide a definitive answer. Because being able to describe your symptoms is so important, this report discusses the variety of symptoms that may occur, and which are typical of particular kinds of arthritis.

In addition, you will find here detailed information and specific treatment advice for the two most common types of arthritis, osteoarthritis and rheumatoid arthritis, along with a brief look at other types of arthritis, such as gout, pseudogout, ankylosing spondylitis, and infectious arthritis.

Because living with arthritis requires more than finding a drug treatment, this report also provides advice about how to exercise safely, cope with emotions, and evaluate whether complementary therapies, such as glucosamine and chondroitin supplements, are right for you.

Millions of people live with arthritis, but this report will suggest ways to live.

What is arthritis?

The word arthritis is derived from the Greek word(joint) and suffix(inflammation). For people who have arthritis, the word variously signifies pain, swelling, redness, and heat that may be caused by tissue injury or disease in the joint.

Osteoarthritis is the most common type of arthritis. It is called a degenerative joint disease because it results from the deterioration of the bones and cartilage that make up the joints. The second most common type of arthritis, rheumatoid arthritis, is an inflammatory disease that affects the lining of multiple joints, especially in the hands and feet. Although it affects only one-tenth as many people as osteoarthritis, it can be far more debilitating. The other rheumatic diseases discussed in this report ? gout, pseudogout, ankylosing spondylitis, reactive arthritis, psoriatic arthritis, enteropathic arthritis, and infectious arthritis ? are also characterized by inflammation.

The musculoskeletal system

All types of arthritis affect the musculoskeletal system in some way, although the joints involved and the means of damage may vary.

The arrangement of bones and muscles in the body is a marvel of engineering. A model of a skeleton may look rickety and frail, but bones have a compression strength equaling that of cast iron or oak. Although incredibly light ? the average adult skeleton weighs only 20 pounds or so ? bones are capable of bearing tremendous weight. Their strength is necessary to withstand the forces of movement. When you walk at a leisurely pace, each foot strikes the ground with a force about three times your weight. At a brisk walk or run, the pressure increases to five to six times your weight. In other words, a 150-pound person's lower extremities are subjected to 450?900 pounds of force during normal activity.

The arrangement of muscles helps hold the skeleton together and, at the same time, provides a means of moving individual bones. Tendons and ligaments, the structures that bind bone and muscle, are made of connective tissue. The main proteins that make up connective tissue are collagens and elastins, which imbue it with tensile strength and elasticity.

There are three basic types of joints (see Figure 1). Fixed joints, or sutures, are thin bands of fibrous tissue that connect the platelike bones of the skull, allowing the skull to expand and accommodate the growing brain. When brain growth is complete, these fibrous joints disappear as the skull bones fuse together.

Cartilaginous joints contain tough cartilage plates. In the pelvis, these joints permit slight movement of the pubic bones and the sacroiliac joint, where the sacrum (part of the spinal column) and pelvis meet. The disks between the vertebral bones in the spine are thicker and accommodate greater mobility.

The most mobile joints are the synovial joints of the shoulders, elbows, wrists, fingers, hips, knees, ankles, and toes. Surrounding each of these joints is a loose fibrous capsule lined with a thin membrane called the synovium. Synovial joints are designed for a variety of movements that make possible all manner of activity, from playing tennis to playing piano. Some ? for example, the outermost joints of the fingers ? are limited to flexion and extension (bending and straightening) within a single plane. Others, such as the shoulder, wrist, and hip, are capable of complex movements in multiple planes.

Synovial joints, like machines with moving parts, are vulnerable to friction. If a machine's moving parts come in contact with one another, friction will scratch the surfaces and cause pitting, distortion, and eventually breakage. As any do-it-yourselfer knows, you can prevent such friction in two ways: Apply a lubricant, or insert a cushion, such as a rubber gasket. Human joints are protected in both ways (see Figure 2).

Synovial fluid is a viscous, yellowish, translucent liquid. Produced by the synovium, it oils the joint and minimizes friction. It also helps protect joints by forming a viscous seal that enables abutting bones to slide freely against each other but resist pulling apart. When a joint is moved quickly or forcefully, this seal breaks, making a popping sound. Places where tendons and muscles cross a bone or other muscle are also subject to friction. These sites are protected by bursae, sacs which not only contain lubricating fluid but also act as cushions.

Articular cartilage, a tough and somewhat elastic tissue that covers the ends of bones, provides joint cushioning. Because it's about 75% water, cartilage compresses under pressure (as occurs with jumping or even walking) and resumes its original thickness when the force is released, much like a very tough sponge. Because the articular cartilage can assume a shape or mold, the opposing surfaces of a joint are perfectly matched.

Several things maintain stability through a joint's range of motion so that the joint can function normally. One is the contour and fit of the joint surfaces themselves. The hip, for example, is a ball-and-socket arrangement. With each stride, the head of the femur (thighbone) pushes deep into the cup-shaped cavity of the pelvis, providing maximum stability during walking. Most other joints are more like hinges.

Also helping to maintain bone alignment are the ligaments ? tough, slightly elastic, fibrous bands that bind the bones together. For example, ligaments on either side of the finger joints prevent side-to-side bending, while ligaments stretching across the palm keep the fingers from bending too far backward.

Muscles and tendons, the fibrous cords that attach muscle to bone, stabilize joints as well as move them. The best example of how this works is in the shoulder, which has such a wide range of motion that ligaments would impede it. While the large, visible shoulder muscles supply the power to move the shoulder, the small rotator cuff muscles and tendons keep the head of the humerus (upper arm bone) from slipping out of the glenoid fossa, a shallow cuplike indentation in the shoulder blade.

The immune system

Inflammation is the hallmark of a number of types of arthritis, including rheumatoid arthritis, gout, pseudogout, ankylosing spondylitis, reactive arthritis, psoriatic arthritis, enteropathic arthritis, and infectious arthritis. Such conditions all appear to stem, directly or indirectly, from an inflammatory response instigated by the immune system.

In inflammatory rheumatic diseases, the immune system reacts to elements that the body perceives as foreign ? be they actual invaders, such as bacteria, or simply cell components wrongly identified as foreign. Research shows that certain people may be more genetically susceptible than others to such inflammatory rheumatic diseases.

The skin covering your body and the mucous membranes lining your respiratory system and gastrointestinal tract are protective barriers that keep out most of the harmful substances in the environment that might enter your body. When these barriers are insufficient, the immune system activates special cells, proteins, and powerful chemicals to eradicate the invader. Although surveillance and policing go on quietly all the time, major confrontations can result in inflammation and tissue damage.

When bacteria, viruses, or other foreign substances invade the body, specialized cells release cytokines, chemical messengers that increase blood flow to the site and direct an army of white blood cells, microbe-fighters, and other protective substances to flow into the invaded tissue. Here, white blood cells release potent chemicals including leukotrienes, prostaglandins, and additional cytokines. These and other chemical mediators are responsible for intense reactions that include inflammation in the form of pain, redness, swelling, and heat. After the attackers have been eradicated, the immune system is no longer stimulated, and the symptoms of inflammation subside.

In order for this process to occur, however, the immune system must first identify the invaders as "non-self" in contrast to normal "self" cells. This requires a complex interaction of numerous recognition and signaling molecules. In simplified terms, the immune system works via several types of cells. First, cells known as phagocytes encounter the invaders, digest them, and present an antigen (a distinguishing protein or carbohydrate) on their surface (see Figure 3). The antigen binds to a special molecule called a human leukocyte antigen (HLA) complex, which in turn presents it to a second class of immune cells launching an attack on the "non-self" invaders.

This second cell type includes several classes of lymphocytes (white blood cells). T lymphocytes recognize the antigen signal and recruit killer lymphocytes to destroy the foreign cells. At other times, T lymphocytes stimulate B lymphocytes to make antibodies, proteins that are designed especially to attack the invader. Natural killer cells and macrophages are other white blood cells involved in fighting foreign molecules. The immune system can also target body cells that become abnormal because of injury, cancerous transformation, or invasion by certain viruses.

Given this complexity, it's not hard to imagine how autoimmune injury might occur. Antibodies made against foreign molecules might mistakenly attack normal body proteins; lymphocytes might misidentify "self" and "non-self" cells; or normal cells could get caught up in the immunological crossfire of harmful enzymes and toxic molecules.

Inflammatory rheumatic disease occurs when something goes awry with the immune response, perhaps because B lymphocytes continue producing antibodies or because the "self" tissues are affected in some way by the original attack that makes them seem "foreign." However it occurs, the result is an inflammatory response that continues far longer than it should.

This prolonged inflammation can be devastating. In rheumatoid arthritis, inflammation may involve internal organs as well as joints. And in ankylosing spondylitis and related disorders, inflammation often centers on an enthesis, a spot where tendons or ligaments attach to bone. The different patterns of tissue damage account for the symptoms that are unique to each of these ailments.

It's become clear that for most forms of inflammatory joint disease, the cause isn't a single infectious agent that could affect anyone. Rather, such diseases occur through a combination of several inciting events in an individual who is genetically susceptible or predisposed at a given time by otherwise unrelated factors.

Much like fingerprints, each person's immune response is unique. This is because a group of genes that regulate the immune system can produce responses to a very large array of potential antigens. On the short arm of chromosome 6 lies an area called the major histocompatibility complex (MHC), containing genes that underpin the immune response.

These genes function as a sort of headquarters for the immune system by determining the structure of the HLA molecules that present antigens to T lymphocytes and enable immune cells to distinguish "self" from "non-self." They were first discovered in the 1950s when immunologists were trying to understand why organ transplants were often rejected by the recipient's immune system. This line of research led to the discovery that people who received transplants had a better chance of recovery if certain of their HLA molecules matched the donor's.

A number of HLA molecules are associated with particular types of inflammatory arthritis. For example, a genetic marker for HLA-B27 is present in nearly all people who have ankylosing spondylitis and in most of those with reactive arthritis, which is triggered by bacterial infection elsewhere in the body. Similarly, a genetic marker for HLA-DR4 can be found in many people with rheumatoid arthritis.

Diagnosing arthritis

Diagnosing arthritis poses a significant challenge to any physician because of the sheer number of conditions that can cause joint discomfort and because there are rarely tests available to establish a definitive diagnosis. Consequently, a doctor must rely heavily on your description of symptoms and other relevant information, plus a physical examination. That's why you should prepare for your appointment by making a list of your symptoms and the circumstances under which they occur. Do you notice them during or after a particular activity? Or first thing in the morning?

Primary care doctors can usually determine at the first visit whether the problem is a form of arthritis or some other musculoskeletal problem. But it may take several visits for your physician to make a more specific diagnosis. While this delay can be frustrating for the patient and family, charting the course of your symptoms is often the only way a doctor can accurately diagnose arthritis.

Your medical history

Your symptoms ? what they are, when they first began, and how they've changed over time ? provide potent clues to whether arthritis is inflammatory or noninflammatory. Your doctor will need to know about the following:

• type of joint symptoms (such as pain or stiffness)

• effect of activity (such as increased pain or relief of stiffness during or after a particular activity)

• general pattern of joint symptoms (started gradually or suddenly, worsened over time or stayed about the same, migrated from one joint to another, or fluctuated in intensity)

• any other symptoms (fever, fatigue, weight loss, skin problems, bowel problems)

• events that occurred near the time the symptoms first appeared (such as viral illness, bacterial infection, injury, vaccination, new medication, or change in activity)

• time of day that joint symptoms are worst (prolonged morning stiffness suggests inflammatory arthritis; night pain is more typical of noninflammatory joint disease)

• presence or absence of joint swelling, redness, or warmth

• previous episodes of similar symptoms

• family history of arthritis or rheumatic disease.

Pain and stiffness

In rheumatic diseases, pain and stiffness go hand in hand. Pain is a subjective experience that's often difficult for people to describe, quantify, or even pinpoint. Chronic arthritis produces aching pain when the affected joints are moved, as opposed to burning or prickling pain unrelated to motion that typifies neurologic disorders. Most people can describe the location of pain in small joints, such as the hands or feet. However, with large joints, the pain is generally more diffuse and may radiate, making it difficult to pinpoint. For example, hip arthritis may cause pain in the groin, thighs, buttocks, or even knees.

People often describe vague muscle aches as stiffness, but rheumatologists use the term more specifically for joint discomfort when a person attempts to move: Stiffness is the tendency of a joint not to move easily and may be prominent even when joint pain is not. The duration of stiffness in the morning or after any period of inactivity can help doctors distinguish osteoarthritis from rheumatoid arthritis and other types of arthritis.

Mild morning stiffness is common in osteoarthritis and resolves after a few minutes of activity. Sometimes people with osteoarthritis notice more stiffness during the day after resting for an hour or so. In rheumatoid arthritis, however, morning stiffness may not begin to improve for an hour or longer. Occasionally, morning stiffness is the first symptom of rheumatoid arthritis.

The nature and duration of your joint symptoms can be helpful. For example, pain and stiffness that develop gradually and intermittently over several months or years suggest osteoarthritis. Rheumatoid arthritis or another inflammatory arthritis may cause pain, stiffness, and fatigue that worsen over several weeks or a few months. In contrast, sudden pain is more likely to be due to an injury or fracture, and pain that intensifies over several hours is typical of bacterial infection or gout.

Physical examination

Because many other disorders can masquerade as arthritis, a complete physical examination is a necessary part of the diagnostic process. During your visit, the doctor watches how you move and looks at joints for abnormalities. The doctor moves your joints through their range of motion to detect any pain, resistance, unusual sounds, or instability. The doctor also gains information from a visual assessment of how you use your joints, and so may ask you to take a few steps, move your hands and arms, and so forth.

Swelling. An inflamed synovial membrane often produces mild joint swelling. People may describe a sensation of tightness or fullness inside the joint, or it may feel tender. Doctors describe the joint as feeling "boggy" or soft to the touch. Marked swelling usually indicates excessive joint fluid, a sign of inflammation or perhaps bleeding into the joint.

Enlargement. Enlargement of a joint is not the same as swelling. Bony enlargement without joint swelling feels hard to the touch and is not usually tender. This finding is typical of osteoarthritis, although it may also occur in people who have no joint pain and as a consequence of other joint disease, such as rheumatoid arthritis.

Limited motion. Doctors assess joint mobility in two ways: active range of motion in which the person voluntarily moves the joints, and passive range of motion in which the examiner moves the person's joints. By comparing active and passive movement, doctors can often determine whether the cause is muscle weakness, bursitis, or tendonitis (in which case the joint has wider range of motion during passive movement), or whether the problem is with the joint itself. Doctors listen and feel for crepitus, a crunching or grating sensation that is sometimes audible and is caused by rough surfaces rubbing together inside the joint.

Spine flexibility. To evaluate spine flexibility, the doctor may ask you to stand and, without moving your pelvis, bend forward as if touching your toes, bend backward, lean from one side to the other, and twist your upper body from side to side.

Diagnostic studies

In most types of arthritis, laboratory tests and x-rays or other imaging techniques may be helpful, but by themselves rarely provide enough information for doctors to establish a specific diagnosis. However, there are exceptions. A bacterial infection of the joint, gout, and pseudogout can be diagnosed by removing and testing a sample of joint fluid (see "Arthrocentesis"). X-rays are occasionally diagnostic as well. For example, x-ray abnormalities in the pelvis and spine may reveal ankylosing spondylitis (see "Diagnosing ankylosing spondylitis").

Doctors often order a complete blood cell count and blood chemistry tests to look for evidence of systemic diseases, including anemia and infection.

Antibody tests. These tests detect various antibodies whose presence may suggest particular types of arthritis. When rheumatoid arthritis is a possibility, many doctors order a test for rheumatoid factor, an antibody that's present in 70%?80% of people with rheumatoid arthritis. But the test is not definitive, so often a second, newer blood test, the anticitrullinated cyclic protein (anti-CCP) test, will usually be ordered as well (see "Blood tests for rheumatoid arthritis"). Antibody tests also exist for other types of arthritis. When lupus is a consideration, for example, doctors will often order a blood test to detect antinuclear antibodies (ANAs).

Erythrocyte sedimentation rate and blood level of C-reactive protein. These blood tests are general measurements of inflammation of any kind: The higher the result, the more severe the inflammation. Most people with osteoarthritis have normal values, but those who have inflammatory conditions, such as rheumatoid arthritis, usually have elevated levels (see "Blood tests for rheumatoid arthritis").

Serum uric acid test. This test measures the level of uric acid in the blood, which is usually elevated in people with gout (see "Diagnosing gout").

Other blood tests. A person's history may indicate the need to test for Lyme disease or other infections, which can cause reactive arthritis and other types of infectious arthritis.

Doctors may order one or more imaging tests to better evaluate your joints. The type of test ordered depends on the suspected diagnosis.

X-rays. Most forms of arthritis can cause joint abnormalities that are detectable on x-ray examination (see Figure 4). But in most cases, such changes can't be detected until months after the onset of the disease. Sometimes the changes are reasonably specific and suggest a particular kind of arthritis. In other cases, they are more general. For example, bone damage (called erosion) is often found in rheumatoid arthritis and may occur in gout, but the damage from each cause differs enough in appearance that a radiologist can often tell them apart.

Often, the changes revealed in x-rays bear little relationship to the actual symptoms, especially in osteoarthritis. An x-ray showing large bone spurs on the finger joints may belong to a woman with occasional mild aching in her hands, while an x-ray revealing much less dramatic abnormalities may be that of a woman who can no longer garden because of hand pain.

In their early stages, osteoarthritis and rheumatoid arthritis may appear quite different on x-ray examination, but later they may look similar. In rheumatoid arthritis, the pannus (inflamed tissue) erodes cartilage, and in many cases, the joint damage eventually leads to secondary osteoarthritis, even after the inflammation subsides.

Magnetic resonance imaging (MRI). In evaluating patients with joint problems, this test is helpful to assess soft tissues, cartilage, tendons, and joint inflammation. It's also quite good for spinal cord and nerve root compression that can be caused by spondylitis or degenerative disk disease. MRI has been used to help diagnose rheumatoid arthritis, although some fear it is being overused in this regard (see "Diagnosing rheumatoid arthritis").

Scintigraphy. Another technique for detecting bone abnormalities is scintigraphy, usually done as a whole-body scan several hours after a special radioisotope (a radioactive dye) is injected into a vein. Scintigraphy does not provide as much specific information as MRI, but it can be useful for detecting bone disease.

Other tests. Researchers are studying the ability of ultrasound to detect erosions in rheumatoid arthritis and other types of arthritis. This type of test uses sound waves to assess fluid in soft tissues and abnormalities in muscles or tendons.

Doctors occasionally order computed tomography (CT) scans to evaluate joints for hidden fractures, torn cartilage, and other structural abnormalities. CT imaging uses a rotating x-ray tube housed in a doughnut-shaped machine to take thin-slice x-rays of your anatomy. A computer then assembles these slices into a three-dimensional picture.

People with sudden or unexplained joint swelling may undergo arthrocentesis, in which a physician removes some of the synovial fluid for examination. Excess synovial fluid may indicate a bacterial infection in the joint, crystal deposits, injury, bleeding into the joint, or synovial inflammation. In cases of relatively mild chronic arthritis, arthrocentesis may help distinguish between osteoarthritis and inflammatory joint disease; this can help to narrow down the diagnostic possibilities and guide treatment.

This procedure can be done in the doctor's office and only takes a few minutes. First the skin over the joint is cleaned and an anesthetic agent (typically given by injection under the skin or as a spray) is used to numb the area. The doctor then inserts a needle through the numbed area into the joint space and withdraws some synovial fluid.

Physicians can often get a good idea of whether the problem is inflammatory by the appearance of the fluid. Normally it's translucent and pale-to-medium yellow. Significant inflammation may produce a deep yellow or greenish-yellow opaque fluid. Cloudy fluid may be a sign of crystals or infection.

Laboratory technicians examine the fluid under a microscope for crystals that indicate gout or similar disorders. Your doctor often requests other laboratory tests on the fluid, such as a white blood cell count; a large number of white blood cells could indicate either infection or severe inflammation. Arthrocentesis itself is often beneficial because removing some of the excess synovial fluid can relieve pain and pressure.

Osteoarthritis

Osteoarthritis is a form of joint disease that develops when cartilage deteriorates. Over time, the space between bones narrows and the surfaces of the bones change shape, leading eventually to friction and joint damage (see Figure 5). Osteoarthritis often affects more than one joint, and while it can affect any joint in the body, some joints are affected much more often than others. For example, osteoarthritis is quite common in the hip, knee, lower back, neck, and certain finger joints, but it is rare in the elbow.

Osteoarthritis is the most common of all joint diseases, accounting for about half of arthritis diagnoses in the United States. It affects approximately 21 million Americans. But these numbers only hint at the impact of osteoarthritis, which can send people to pain clinics and doctors' offices, make them reach for medications, keep them home from work, and curtail leisure and everyday activities. Because the risk of developing osteoarthritis increases with age, this form of arthritis is expected to become even more prevalent as the population of the United States grows older.

About equal numbers of men and women have osteoarthritis, but it tends to affect them differently. Men typically develop symptoms before age 45, while women usually don't have symptoms until after age 55. Women more often have osteoarthritis in the hands and knees. Men are more likely to have it in the hips, knees, and spine. Women are 10 times more likely to develop Heberden's nodes, a type of osteoarthritis in which hard, bony growths form on the joint nearest the fingertip.

More than wear and tear

Osteoarthritis is virtually unheard of in children and is rare in young adults. But it's common among older people. Almost everyone over age 65 has some cartilage and bone changes typical of the disorder. For this reason, osteoarthritis was long considered a natural product of aging, reflecting everyday wear and tear on cartilage. Although this attitude still prevails among many physicians, experts now believe the cause is much more complex. External factors, such as injuries, are important initiators, but the rate of progression is probably also affected by genetic and environmental traits.

While it's true that one's risk of developing osteoarthritis symptoms increases with age, many people whose x-ray films indicate joint changes typical of osteoarthritis have no symptoms. The severity of osteoarthritis symptoms depends on many factors, including how people use their joints. That's why taking the time to protect your joints is so important (see "Joint protection strategies").

The first signs of osteoarthritis are microscopic pits and fissures in the surface of the cartilage in your joints (see Figure 5). These fissures indicate that biochemical changes are gradually making the cartilage less resilient. Cartilage cells themselves produce enzymes that damage the molecules making up the structure of the cartilage, and tiny pieces of cartilage may flake off into the joint cavity. This changes the shape of the cartilage lining the bone, causing further damage as the altered surfaces move against each other.

As cartilage degenerates, patches of exposed bone appear. Just as a damaged gasket leads to metal-on-metal contact in a machine, your bones experience mechanical friction and irritation. They try to repair themselves, but the repair is disorderly. As a result, the surface thickens and osteophytes (bone spurs) form.

Once your cartilage is damaged, the resulting abnormalities can irritate surrounding soft tissues and cause inflammation. People with severely damaged joints sometimes have episodes of joint swelling from synovitis (inflammation of the joint's lining); however, this inflammation tends to be much milder than in rheumatoid arthritis or other inflammatory joint diseases. The damaged cartilage, bone rubbing on bone, and the inflammation combine to make movement painful.

Doctors sometimes refer to osteoarthritis as noninflammatory to distinguish it from other rheumatic diseases. But many people with osteoarthritis experience low-grade inflammation. It may arise when the articular cartilage in your joint fails to recover fully from an injury. In addition, inflammation may reflect an attempt by the joint to repair damage, or it may be due to genetic or metabolic factors that predispose you to joint degeneration.

Possible causes of osteoarthritis

Doctors may categorize osteoarthritis as primary, meaning the principal cause is unknown. However, excess weight and genetics also contribute to predisposition. Or the disease may be categorized as secondary, originating from trauma, such as a blow or injury, or a recognizable disease process, such as hemophilia. Some scientists believe primary osteoarthritis begins with repeated minor injuries. The cartilage is able to repair itself for a time, but eventually this effort fails.

By now, everyone has heard that carrying excess body fat can lead to problems with the heart and other organs. Here's another reason to slim down: Overweight people are much more likely to develop osteoarthritis of the knee. These weight-bearing joints just don't hold up well under the continued strain of extra pounds ? and extra pounding.

An ongoing study of people living in Framingham, Mass., found that overweight young adults were more likely to develop knee osteoarthritis in their 30s and 40s than were their slimmer counterparts. Women who were the heaviest were twice as likely as thinner women to get osteoarthritis and had three times the risk for severe knee osteoarthritis. Losing weight can reduce risk. Researchers who analyzed the Framingham data found that women who lost 11 pounds cut their risk of developing osteoarthritis of the knee by half.

Consensus is growing that genetic factors likely control the manifestations and progression of osteoarthritis. Studies in identical twins ? who share the same genes and thus offer insight into the relative importance of genetic and environmental factors ? have shown that roughly half the risk of developing osteoarthritis can be attributed to genetic factors. Multiple genes are thought to be involved, and to complicate matters further, the genes may have different effects depending on the joint affected and whether someone is male or female.

Genetic studies of a disease like osteoarthritis are hampered by several factors. First, the sheer number of people with the disorder makes it impossible to discount the influence of external factors. Second, scientists must establish that a certain gene is present in most people with the disease, but is absent in those who are healthy.

Osteoarthritis is common among postmenopausal women. One study found that women who were taking estrogen replacement therapy appeared to have a lower risk of developing the disease, suggesting that estrogen may have a protective effect on cartilage in much the same way that it protects bones from osteoporosis. However, these findings remain controversial: Estrogen has many, and in some cases conflicting, effects on connective tissue and bone, making the association between estrogen and arthritis difficult to sort out.

Postmenopausal women tend to have either osteoarthritis or osteoporosis, but not both. This may be because the bones of thinner people are less dense and more susceptible to osteoporosis; heavier people, who have higher bone density, are less prone to osteoporosis but more susceptible to arthritis from greater stress on joints.

Injury to a joint, either because of repeated use or trauma, may also cause osteoarthritis. As many athletes know, severe knee trauma disrupts the normal mechanics of joint function. Nearly all tissues heal by scarring, leaving irregularities on their surfaces. Because bones, joints, or muscles that are damaged rarely heal perfectly, joint injuries can create unusual mechanical stresses that lead to abnormal wear. People in certain occupations are prone to develop osteoarthritis in those joints subjected to the most stress. For example, osteoarthritis may affect the hips, ankles, and feet of ballet dancers, the knees of soccer players, the hips of farmers, the elbows of riveters, and the hands and wrists of pneumatic tool operators. The cause is thought to be repetitive stress leading to bone fatigue, microscopic fractures, and eventually cartilage breakdown.

Even those who are sedentary can develop occupational osteoarthritis when repetitive stress is sustained for several hours a day. Perhaps surprisingly, people who spend a lot of time using a keyboard aren't more likely to develop osteoarthritis of the hands, because typing puts very little mechanical stress on the joints.

Osteoarthritis can also develop in a joint damaged by a related disease, such as rheumatoid arthritis, infectious arthritis, or gout. Or osteoarthritis may develop because of hemophilia, growth abnormalities, or hereditary metabolic diseases. Hemophilia can produce osteoarthritis as a result of bleeding in the joint.

Growth abnormalities that can lead to osteoarthritis include acromegaly and slipped femoral epiphysis. Acromegaly is characterized by the irregular overgrowth of bone and cartilage due to abnormal production of growth hormone. Slipped femoral epiphysis involves displacement of the growth plate at the end of the femur, the bone that extends from hip to knee. Osteoarthritis can also arise from hereditary metabolic diseases, such as hemochromatosis (the harmful accumulation of iron in tissues).

Symptoms of osteoarthritis

The symptoms of osteoarthritis usually develop over many years. Often, people first experience pain after engaging in strenuous activity or overusing a joint. The joint may be stiff in the morning, but after a few minutes of movement, it loosens up. Gradually, this stiffness becomes a routine part of waking up.

Cartilage is insensitive to pain, but the soft tissue in the joints is not. As more cartilage is worn away, soft tissue becomes increasingly irritated, even by slight movement. Some people have continual joint pain that interferes with sleep. Or the joint may be mildly tender, and movement may produce crepitus, a sensation of crackling or grating. In addition, gradual joint enlargement may interfere with normal mobility. Swelling may also occur as synovial tissues become irritated, or when inflammation develops. Although inflammation is not a cardinal feature of osteoarthritis, it does sometimes occur. Pain usually occurs in the affected joint, although it may extend elsewhere.

When osteoarthritis affects the knee, the result is pain, swelling, and stiffness of that joint. What starts out as some discomfort after a period of disuse can progress to difficulty walking, climbing, bathing, and getting in and out of bed.

Osteoarthritis of the hand often starts with stiffness and soreness of the joint at the base of the thumb, particularly in the morning. You may find it becomes harder to pinch, and your joints crackle when moved. As the condition worsens, the pain at the base of your thumb can become more of a problem, and your ability to pinch decreases even further. The entire area may seem unstable. People with osteoarthritis of the hand may eventually find it impossible to open jars, turn a key, write, or type. Many people with osteoarthritis of the hand find that, with age, their hands thicken and become stiff. Stiffness is gradually followed by pain or instability. In other people, the pain and stiffness of hand osteoarthritis may subside over time, despite marked bony enlargement typical of the disease.

Radiating pain is often the most striking feature of hip and spine osteoarthritis. When osteoarthritis affects your hip, you may feel pain in the groin or down the inside thigh, or pain may radiate to your buttocks or knee. Osteoarthritis of the cervical spine (neck) may cause pain in your shoulders and arms. In the lower spine, osteophytes may impinge on adjacent nerves and send pain radiating to your buttocks or legs.

For most people, osteoarthritis develops gradually. Pain and stiffness in affected joints may slowly worsen, but most people are able to lead normal lives.

Diagnosing osteoarthritis

Diagnosis is usually straightforward and is based on a person's symptoms and medical history (see "Diagnosing arthritis"). When symptoms don't fit the usual pattern for osteoarthritis, further investigation, often by x-ray or other imaging techniques, may be necessary. Such atypical examples may involve arthritis of joints that are usually spared, such as the elbow, shoulder, or ankle, or swelling of the synovium, a condition known as synovitis.

Drug treatment for osteoarthritis

Although no drug exists that will cure or reverse the progression of osteoarthritis, it is usually possible to alleviate pain and inflammation. Medications form the basis of treatment for osteoarthritis, but are best used in conjunction with other pain relief strategies, such as exercising to build your muscles and protecting your joints from injury or overuse (see "Slowing the progression of osteoarthritis").

Topical analgesics, which are applied to the skin, offer one alternative for mild pain relief. You can use these alone or in combination with one of the medications described below. Creams containing salicylate, such as Aspercreme or Bengay, and others containing capsaicin, such as Zostrix, are available over the counter. However, it's important to avoid touching any mucous membrane (for example, around the mouth, nose, or eyes) after applying the cream, to avoid irritation.

To relieve the pain and stiffness of osteoarthritis, the first step is usually an over-the-counter pain reliever. Doctors often recommend acetaminophen (Tylenol) first because it's often effective for mild pain and easy on the stomach. But remember that acetaminophen, like any drug, has its own risks ? especially for the liver.

A 2005 study inconcluded that acetaminophen was to blame for 42% of the cases of acute liver failure seen at hospitals during the study period. Many of these poisonings were accidental and occurred in people taking the drug regularly for pain relief.

To avoid an accidental poisoning, don't exceed the recommended maximum per day ? generally set at 4 grams (4,000 milligrams), the equivalent of eight extra-strength Tylenol tablets. Remember that acetaminophen is often included in combination formulas, so it's important to read all medication labels carefully. If you drink more than a moderate amount of alcohol on a regular basis (more than two drinks a day for men, and one drink a day for women), it is wise to stay well below the maximum daily dose or avoid acetaminophen altogether, because your threshold for toxicity may be lower than it is for other people.

It has become clear that nonsteroidal anti-inflammatory drugs (NSAIDs) may be more effective than acetaminophen in treating osteoarthritis because they not only relieve pain, but also reduce inflammation that contributes to pain, swelling, and stiffness.

The arsenal of NSAIDs has grown over the years to include about 20 different drugs. Among them are such well-known medications as aspirin, ibuprofen (Advil, Motrin, others), and naproxen (Aleve, Naprosyn, others). These drugs reduce pain and inflammation by blocking the production of prostaglandins, leukotrienes, and other chemical mediators. For many people, they are slightly more effective than Tylenol, especially during flare-ups of pain.

The most common side effects of these medications are stomach problems, including gastrointestinal bleeding and ulcers, often occurring without warning. That is because NSAIDs work by inhibiting both the COX-1 enzyme, which helps protect the stomach lining from the corrosive effects of stomach acids and digestive enzymes, and the COX-2 enzyme, which causes pain and inflammation. One widely quoted paper, published in thein 1999, estimated that each year these drugs contribute to at least 16,500 deaths and more than 100,000 hospitalizations in the United States. A study of people in Spain concluded that roughly one in three hospitalizations or deaths due to gastrointestinal bleeding could be attributed to NSAIDs. It is possible in many cases to avoid such complications ? but first you and your doctor must work together to determine your risk of experiencing them.

The older you are, the higher your risk of developing bleeding and ulcers. Others at risk include people who have had ulcers in the past, people with rheumatoid arthritis, and people who are also taking a blood thinner or corticosteroids. Prolonged use and higher doses of NSAIDs also increase the risk. And some NSAIDs are more prone than others to causing ulcers; for example, aspirin (Anacin, Bayer, others) and indomethacin (Indocin) appear to have the highest risk.

If you are in a high-risk group, you should probably try to avoid NSAIDs if at all possible, and try other pain relief strategies. A COX-2 inhibitor is safer, but the risk isn't zero. If you're in a high-risk group and find that these other strategies don't work, then talk with your doctor about stomach-protecting drugs to take along with the NSAID. These include histamine blockers such as cimetidine (Tagamet) and ranitidine hydrochloride (Zantac), and proton pump inhibitors such as esomeprazole (Nexium), lansoprazole (Prevacid), and omeprazole (Prilosec). Another option is taking misoprostol (Cytotec) with the NSAID. Some medicines (such as Arthrotec or Prevacid NapraPAC) combine a medication that protects the stomach with an NSAID.

If taking NSAIDs produces stomach upset but not a bleeding ulcer, good initial strategies are to reduce the dose of the NSAID you're taking, try an entirely different pain reliever (such as acetaminophen), or switch to a drug that is more selective for COX-2. For example, celecoxib (Celebrex) is a COX-2 selective agent and might be better tolerated than indomethacin. Nabumetone (Relafen), although not officially a COX-2 selective agent, is also relatively selective for COX-2 and would be a better choice than indomethacin if stomach upset is a limiting factor. Other more selective medications to consider, as they may be more easily tolerated, are meloxicam (Mobic) and diclofenac (Voltaren).

No matter what your risk profile, to be on the safe side, use NSAIDs only under the supervision of your doctor, and do not combine NSAIDs with other medications without talking to your doctor first. Also take time at each doctor's visit to reassess the medications you are taking for your arthritis and to evaluate your symptoms. All too often, people are taking more medication than they really need. Other pain relief strategies might be used in combination with the drugs so you can lower the dose.

In 1998, the FDA approved the first of a new generation of NSAIDs. Known as COX-2 inhibitors, these prescription drugs were designed to be more selective in their effects than traditional NSAIDs. COX-2 inhibitors, as their name implies, inhibit only the COX-2 enzyme involved in pain and inflammation, while sparing the COX-1 enzyme that protects the stomach lining. As such, they were able to relieve pain as well as the strongest NSAIDs, while causing less stomach irritation (although the risk of this side effect isn't eliminated).

Eventually the FDA approved three COX-2 inhibitors: celecoxib (Celebrex), rofecoxib (Vioxx), and valdecoxib (Bextra). But today only Celebrex is available in the United States, and it comes with a warning. The manufacturers took Vioxx and Bextra off the market after the FDA warned that these drugs could increase the risk of stroke and heart attack.

This is because both the COX-1 and COX-2 enzymes also exert effects on the arteries. The COX-1 enzyme narrows arteries and makes blood platelets sticky, while the COX-2 enzyme widens arteries. When just COX-2 is blocked, the "widen" signal is lost and the resulting combination of narrowed arteries and stickier platelets can lead to blood clots that block an artery in the heart, causing a heart attack, or one in the brain, causing a stroke.

For this reason, most people now choose to try other pain relief alternatives before taking the remaining COX-2 inhibitor on the market, celecoxib. If you do take this medication, talk with your doctor about how to take it safely, especially if you already have an increased risk of heart attack or stroke.

When osteoarthritis is accompanied by inflammation, as indicated by warmth and an accumulation of fluid in the joint, your doctor may remove a small amount of joint fluid and then inject a corticosteroid. This procedure can relieve inflammation quickly, but usually only for a short time. It is used almost exclusively for severe symptoms associated with these signs of inflammation, especially for osteoarthritis of the knee. This approach is usually used infrequently ? up to three or four times per year ? and only when absolutely necessary, because more frequent injections of these drugs may increase the risk of infection and can damage the joints.

The dietary supplements glucosamine sulfate and chondroitin sulfate are over-the-counter agents that may provide pain relief to people with moderate to severe pain from osteoarthritis (see "Glucosamine and chondroitin").

Injections of hyaluronate (Hyalgan, Synvisc) may provide mild relief of symptoms of knee osteoarthritis in some people. In its natural form, hyaluronate lubricates the joint and supplies it with nutrients. Synthesized forms of this chemical can be injected directly into an osteoarthritic knee once a week for three to five weeks. But the jury is still out on this approach: Some doctors do not believe the modest benefits are worth the risk and discomfort of the injections.

Surgical treatment for osteoarthritis

Sometimes surgical intervention is necessary to relieve extremely painful or badly misaligned joints. The option your doctor recommends will depend on your age, activity level, and overall health. Surgical options are usually recommended only when drug therapies and other strategies have failed.

Arthroscopy is considered minor surgery because the surgical incisions are small and the procedure generally does not require an overnight stay in the hospital. An arthroscope is an instrument with a tiny light, a camera, and a variety of surgical attachments. The surgeon inserts the instrument into the joint and performs minor surgery using the attachments. The camera enables the surgeon to see and smooth over any ragged joint edges and to locate and remove debris and loose material. Depending on the condition of the joint, this can result in mild to moderate improvement that may last several months or perhaps a few years. However, for someone with severe osteoarthritis, this approach is unlikely to offer much benefit. Studies have called into question whether this type of surgery should be routinely employed. Unless there is a specific finding or abnormality that can be addressed with this technique (such as a tear in the cartilage), arthroscopy for osteoarthritis may not be helpful.

Doctors recommend joint reconstruction or replacement in cases of severe osteoarthritis in which the joint shows significant deterioration. Surgery can be used to correct joint deformity, to reconstruct a diseased joint, or to completely replace a diseased joint with a prosthetic device. This surgery is most often recommended for osteoarthritis of the hip or knee, because severe disease of these joints can impede movement.

Hip replacement and knee replacement are among the most common surgeries performed in the United States. A replaced joint will last an average of 10 to 15 years (or even longer, because such estimates are based on operations performed at least 10 years ago). But joint replacement is not an option for everyone; the ideal surgical candidate is in good general health and not overweight. However, as surgical and anesthesia techniques have improved, more and more people are becoming good candidates for surgery. Surgeons may encourage young, physically active people to delay joint replacement because artificial joints usually need to be replaced after a decade or two. The younger the patient, the more the joints are used, and the greater the number of replacements that may be necessary.

It's also important to have realistic expectations about what joint replacement surgery can and cannot do. Joint replacement doesn't guarantee that you will be able to move or use the joint in a normal way. Still, many people do experience great functional improvement. The major consistent benefit is substantial relief from pain. To maximize the chances of good results, it's important to participate in physical therapy after surgery.

Many artificial joints are attached to bone with pins and acrylic cement (see Figure 6). Over time, these components may loosen or break, requiring repairs. Researchers believe some design improvements that have been made may make the implants last longer. For example, cementless components are now widely used. Their metallic surfaces are roughened until they become semi-porous, allowing bone to grow into the surfaces, which may reduce the likelihood of loosening. However, such designs must be tested for 10?20 years to determine how well they perform. These components haven't yet been shown to perform significantly better than a well-cemented pin.

Cartilage transplant is a method to replace damaged cartilage with healthy cartilage transplanted from elsewhere in the body or from donated tissue from someone who has died. Cartilage cells may be removed from a joint or some other area and grown outside the body to form a biological patch. The patch is then inserted in an area of damaged or missing cartilage with an arthroscope. So far, these approaches have been used primarily in young people with small, sports-related cartilage injuries in the knee. But many experts believe that the time is coming when cartilage transplant will be a more common treatment for osteoarthritis.

Slowing the progression of osteoarthritis

Osteoarthritis is a disease that progresses slowly over many years (see "More than wear or tear"). If you've already been diagnosed with osteoarthritis, you can take steps to slow its progression and reduce your discomfort. These measures are most effective if you begin them in the earlier stages of your condition. But no matter how far your osteoarthritis has progressed, you can benefit from the following.

For people with osteoarthritis, regular exercise has been shown to reduce pain and stiffness and to improve balance. Exercise helps people perform such basic activities as walking. It also helps build or maintain muscle tone, which is necessary for joint stability.

There are three types of exercise beneficial for someone coping with osteoarthritis. Range-of-motion exercises can maintain or improve flexibility. Strengthening exercises with weights can build muscles to support affected joints. And aerobic exercises can help improve endurance and prevent weight gain. (See "Exercise" for more information about all of these.)

One study that compared walking and weight training suggests that exercise may help prevent disability. People with knee osteoarthritis who exercised regularly were less likely to need help with daily activities such as getting out of bed, bathing, using the toilet, or getting dressed. The improvements most likely reflected a general improvement in health and functioning, rather than a change in the arthritis itself. The reported improvements were nonetheless substantial.

Try to work your way up to 30 minutes of aerobic exercise ? slow walking, biking, or swimming ? at least four times a week. Add in some resistance or weight-training exercises three times a week.

When exercising, protect yourself from joint injury. For example, if you have osteoarthritis of the hip, knee, foot, or ankle, don't run, especially on roads. Walking is a much gentler form of exercise, although it, too, puts full, weight-bearing stress on some joints. Other good alternatives are non-impact aerobic activities such as swimming or biking.

Invest in a good pair of exercise shoes, which will absorb some of the impact. Avoid repetitive, weight-bearing motion. If you can't avoid such joint stress altogether, take frequent breaks. Remember to bend your knees when lifting heavy objects. Use the largest, strongest joint to complete a task. For example, open a jar with the palm of your hand instead of with your fingers (see "Joint protection strategies").

Osteoarthritis and excess pounds often go hand in hand. For one thing, arthritis promotes inactivity. For another, it affects older people, who tend to be less active. But studies have shown that weight loss reduces osteoarthritis pain. It does so by taking some of the pressure off your joints, especially the weight-bearing joints such as the knees and hips. Losing weight also allows greater ease of movement.

Exercise is the first step toward weight loss. A healthy, well-balanced diet is another. Concentrate on replacing empty calories from desserts and junk food with nutrition-packed calories from whole grains, lean proteins, and fruits and vegetables. Also be sure to control portion sizes. Most experts now agree that virtually any diet program is effective for losing weight when it encourages people to reduce their calorie intake and increase calories burned. Whatever diet strategy you choose, the bottom line is that to lose weight, you have to consume fewer calories than you burn.

Rheumatoid arthritis

The treatment of rheumatoid arthritis has changed dramatically since the 1990s, owing to a better understanding of how to slow the progression of joint damage in this disease. Advances in treatment, discussed below, followed decades of research into how the immune system functions.

Until the mid-1960s, physicians lumped together most forms of arthritis that affected four or more joints as rheumatoid arthritis. Then researchers identified rheumatoid factor, an antibody present in the blood of 70%?80% of people with rheumatoid arthritis. The presence or absence of rheumatoid factor helped physicians distinguish rheumatoid arthritis from other types of inflammatory arthritis that may occur in people who have psoriasis, inflammatory bowel disease, or infectious diseases. Rheumatoid factor may also help distinguish between rheumatoid arthritis and osteoarthritis, because people with osteoarthritis are no more likely to have rheumatoid factor than the general population.

Rheumatoid arthritis is a chronic autoimmune disease in which the body's immune system attacks healthy tissue lining the joints. It affects about three million Americans, and strikes two to three times more women than men. Although the disease usually first appears during middle age, it may occur in the 20s and 30s. Some children develop a similar disease, called juvenile chronic arthritis, but this is considered a separate disorder.

The chronic inflammation of rheumatoid arthritis begins in the synovium, where an unknown event triggers an inflammatory reaction. As a result, synovial and other cells produce cytokines, other chemical mediators, and proteolytic enzymes, which together can destroy all the components of the joint. The synovial tissue also begins to proliferate, causing the normally smooth synovium to form pannus, a rough, grainy tissue that grows into the joint cavity and erodes cartilage (see Figure 7). If the tendons become inflamed, they may shorten and immobilize the joint, which can cause bone fusion and loss of mobility. If the tendons rupture, the joint may become loose or floppy.

Rheumatoid arthritis can affect connective tissue in other parts of the body. Inflammatory skin nodules at pressure points, such as the elbow, can appear gradually or suddenly, and may be tender and sometimes inflamed. Occasionally, surgery is needed if these nodules become infected or are bothersome during activity. At times, they may also disappear spontaneously.

Vasculitis (inflammation of blood vessels) can compromise circulation to the hands, feet, and nerves. People with rheumatoid arthritis often develop eye conditions, including keratoconjunctivitis sicca, or dry eye, which causes redness, burning, itching, reduced tearing, and sensitivity to light. Other complications include respiratory, heart, and neurologic disorders. In rare cases, the ligaments that tether the uppermost vertebrae (which support the skull) are damaged, allowing the vertebrae to slip out of alignment and pinch the spinal cord.

At advanced stages, rheumatoid arthritis can limit a person's ability to carry out normal daily activities such as dressing, bathing, and walking. Those affected often experience feelings of depression and helplessness as the disease progresses. However, medications are now helping to slow the progression of rheumatoid arthritis and make a dramatic difference in the lives of many of those affected.

One of the most important steps you can take if you are diagnosed with the disease is to become an active participant in your own care. This includes working with your doctor so that you can learn to recognize flare-ups and drug side effects, take medication as prescribed, and engage in activities to maintain joint function in order to prevent disability. Balancing rest with activity, dealing with the emotional impact of rheumatoid arthritis, and using splints or assistive devices to protect your joints against overuse are among the most helpful coping strategies (see "Physical and complementary therapies"). The ultimate goals in managing rheumatoid arthritis are to prevent or control joint damage, prevent loss of function, and decrease pain.

Possible causes of rheumatoid arthritis

Scientists don't know what causes rheumatoid arthritis, but they are investigating many hypotheses. The disorder runs in families, is more common among women, and may initially resemble some forms of infectious diseases, such as viral arthritis.

Genetic factors. Rheumatologists have long theorized that some insult (perhaps a microbe or an environmental toxin) triggers rheumatoid arthritis in genetically susceptible people. Now geneticists believe that HLA genes may provide the link. HLA-DR genes ? of which several dozen have now been identified ? are instrumental in identifying and disposing of foreign antigens. Scientists reported in 1978 that 70% of people with rheumatoid arthritis had molecules of certain DR4 subsets on their lymphocytes, while only 28% of healthy subjects had such molecules. Subsequently, several other genes in the HLA family have been implicated as well.

Infectious agents. Scientists have searched ? without success ? for evidence that individuals with rheumatoid arthritis might harbor certain bacteria known to cause other types of arthritis, such as(which causes pneumonia or genital infections) or(one of several sexually transmitted organisms that can cause Reiter's syndrome). A more likely role for bacteria would be through an immune system error: Lymphocytes might produce antibodies against a bacterial product that also react against a connective tissue protein. Other researchers believe that a virus is the most likely culprit.

This form of arthritis attacks multiple joints and is usually symmetrical ? it affects joints similarly on both sides of the body, particularly the finger joints, base of the thumbs, wrists, elbows, knees, ankles, or feet. It nearly always involves the wrists and the middle and large knuckles, but seldom the joints nearest the fingertips (see Figure 8). At times, joint pain may be constant, even without movement. Morning stiffness that lasts for an hour or longer is a hallmark of the disease and one of the main ways doctors gauge the severity of inflammation.

The course of rheumatoid arthritis is unpredictable. Early on, the symptoms frequently abate or even disappear, only to flare up weeks or months later. Occasionally complete remission occurs, usually within the first year. But for some people the process is destructive, ending in severe disability within a few years.

Diagnosing rheumatoid arthritis

People who have symptoms of arthritis should have a complete medical evaluation (see "Diagnosing arthritis"). The symptoms and physical examination are the most important parts of the diagnostic process. The early joint symptoms of other conditions, such as lupus, are sometimes indistinguishable from those of rheumatoid arthritis, making a definitive diagnosis difficult soon after symptoms start. Blood and imaging tests are often ordered to help with diagnosis.

It's important to understand that it may take several weeks (and several visits) before you receive a definite diagnosis. People often find it frustrating to wait, and they worry that they are not receiving prompt treatment. But you may find it reassuring to know that a few weeks' delay will not jeopardize your health, whereas undergoing the wrong therapy could.

Your doctor may order several types of blood tests, because no one test is sufficient to confirm a diagnosis.

Rheumatoid factor. The vast majority (70%?80%) of people with rheumatoid arthritis have an abnormal antibody called the rheumatoid factor in their blood, so you will probably undergo a simple blood test for this antibody. Just be aware that if rheumatoid factor is detected in your blood (meaning the test is positive), it doesn't necessarily mean that you have rheumatoid arthritis. About 10% of people who do not have rheumatoid arthritis will test positive for rheumatoid factor. Such people may either be perfectly healthy or suffering from another disorder such as systemic lupus erythematosus (see "Related disorders"). At the same time, some people with rheumatoid arthritis will test negative for rheumatoid factor. Thus your doctor is likely to order additional blood tests to look for causes of joint pain.

Anti-CCP. The anticitrullinated cyclic protein (anti-CCP) test measures the presence of an antibody associated with rheumatoid arthritis. The anti-CCP test is gradually becoming more common. (Indeed, some rheumatologists now order it routinely whenever they order a rheumatoid factor test.) Some small early studies have shown that the anti-CCP test can reliably help to diagnose rheumatoid arthritis in three types of people: those with early-stage disease for whom uncertainty remains about diagnosis, those with mild symptoms who test negative for rheumatoid factor, and those who test positive for rheumatoid factor but may suffer from some other condition. Researchers do not yet know whether the anti-CCP test is useful in other circumstances, or whether the anti-CCP test offers much benefit beyond standard clinical tests.

ESR. The erythrocyte sedimentation rate (ESR) provides a measure of body-wide inflammation: The higher the rate, the greater the likelihood that you are suffering from inflammation, which could be caused by rheumatoid arthritis. This test can also help determine how serious your condition is.

CRP. The C-reactive protein (CRP) test also measures inflammation, but tends to change more rapidly than the ESR; minor elevations have also been associated with an increased risk of cardiovascular disease. In assessing inflammation due to rheumatoid arthritis, this test offers no clear advantages over the ESR.

Since rheumatoid arthritis often involves the hands and feet, your doctor may also order x-rays and possibly magnetic resonance imaging (MRI) of these joints and others to check for bone erosions. Initial studies of MRI show that it is better at detecting bone erosions than x-rays, but its use is controversial because it may detect cysts or other bone changes that resemble erosions, and thus could lead to unnecessary treatment. The issue is important, because rheumatoid arthritis is a disease that varies greatly in its progression and impact: Treatment should be directed by symptoms, findings on physical examination, the results of joint imaging, and preferences of the patient, not just by the results of a single imaging test. In addition, MRI is expensive, and routine use could drive up the cost of caring for people with rheumatoid arthritis dramatically.

Medications for rheumatoid arthritis

In the 1990s, the treatment of rheumatoid arthritis changed significantly, as researchers developed medications to treat this disease. In the past, doctors treated rheumatoid arthritis very conservatively. But evidence that joint damage starts early in the course of the disease has prompted physicians to treat it more aggressively from the beginning.

Given the complex nature of rheumatoid arthritis, and the fact that its progression varies from person to person, there are no easy answers when it comes to deciding on a treatment plan. In general, it is best to wait six to eight weeks to allow for a definitive diagnosis and to see how you respond to initial treatment before committing to long-term aggressive medical therapy. It is also important to remember that treatment should be tailored to the individual: Although some people with rheumatoid arthritis begin aggressive therapy within weeks of diagnosis, others may not need it right away.

Drugs for rheumatoid arthritis fall into several classes (see Appendix), and may be given in combination or sequentially. Although newly approved drugs tend to generate a lot of excitement, it's best to be cautious when using any new drug. The withdrawal of two COX-2 inhibitors from the market because of safety concerns shows dramatically that the true benefits and risks of any medication may not be known for years. Studies conducted to gain FDA approval for a drug may enroll no more than a few hundred or a few thousand people, who may be healthier than those who take the drug after it is approved. What's more, pre-approval studies are often limited in duration, while people taking the drugs for a disease like rheumatoid arthritis may take them for years. Uncommon side effects, interactions with other drugs, and long-term side effects only emerge in the general population in the years following approval. Unfortunately, there is no system in place to reliably identify these problems sooner. For all these reasons, make sure you understand and carefully weigh the risks and benefits before deciding to try a novel therapy.

To alleviate the pain and inflammation of rheumatoid arthritis, most doctors prescribe a nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen, or a COX-2 inhibitor, such as celecoxib (Celebrex).

Although anti-inflammatories can provide considerable benefit, they may also have a variety of side effects. If you are considering long-term use of any NSAID (including a COX-2 inhibitor), it is important to talk with your doctor about your personal health risks, particularly any gastrointestinal problems you may have. (For more on these medications, see "NSAIDs" and "COX-2 inhibitors.")

Although NSAIDs and COX-2 inhibitors can reduce pain and swelling, they have little if any effect on the disease process involved in rheumatoid arthritis. As a result, most people with rheumatoid arthritis need disease-modifying antirheumatic drugs (DMARDs) to control disease activity.

Disease-modifying antirheumatic drugs usually are used as first-line therapy in rheumatoid arthritis. They have the potential to slow the progression of rheumatoid arthritis by altering the function of the immune system. Because these medications can reduce or prevent joint damage and preserve joint function, they have become the standard of care for people with ongoing symptoms or joint damage.

DMARDs may be prescribed alone or in combination with drugs from other categories. Methotrexate (Folex, Rheumatrex, Trexall), when carefully prescribed, has an excellent safety profile, is highly effective, and is usually the first choice of therapy. It's also the drug against which all newer agents are judged. For example, leflunomide (Arava), a newer DMARD known as an immunomodulator, is proving to be as effective as methotrexate, and it has a different, but acceptable, safety profile. Like methotrexate, leflunomide can lead to liver toxicity. And it shouldn't be taken by anyone with compromised kidney function.

Other commonly prescribed DMARDs include hydroxychloroquine (Plaquenil) and sulfasalazine (Azulfidine), although often these are chosen for mild disease, in combination with methotrexate or when methotrexate is not tolerated. Additional options include gold salts (Myochrysine), cyclosporine (Neoral), and penicillamine (Cuprimine, Depen), but these are used much less often because they appear to be less effective or less safe, or both.

Although DMARDs are often highly effective, their toxicity may extend to frequently proliferating cells that are vital to the body's renewal processes. For example, they may have damaging effects on the bone marrow, bladder, lung, liver, intestine, and reproductive organs. They also carry the risk of birth defects if taken by pregnant women. Anyone taking a DMARD is regularly monitored and may need to have frequent, complete blood cell counts, liver function tests, and urinalyses. The specific monitoring tests and frequency of testing vary depending on the drug taken.

One thing to keep in mind is that DMARDs are slow-acting drugs. Do not become discouraged and stop taking a DMARD before it has had a chance to work. Your doctor will probably advise you to take an NSAID, a corticosteroid, or both during the early weeks or months of treatment until the DMARD begins to take effect. Failure to respond to one DMARD does not mean you will also fail to respond to a different DMARD.

Biological response modifiers are a type of DMARD designed to alter the function of cytokines, signaling molecules that help mount an inflammatory reaction. These drugs may be able to do what other drugs have failed to do so far: stop the rate of joint deterioration.

Anti-TNF agents. These drugs block the action of tumor necrosis factor (TNF), which appears to be a primary instigator of joint inflammation (see Figure 9). Three anti-TNF agents are now available: adalimumab (Humira), etanercept (Enbrel), and infliximab (Remicade). About 60%?70% of people with rheumatoid arthritis respond well to anti-TNF agents.

In a number of people with rheumatoid arthritis, these drugs have induced something close to remission. However, like anti-cancer chemotherapy, these drugs are potent and expensive. In addition, infliximab requires frequent visits to the hospital for infusions. As such, anti-TNF agents may be too aggressive for people with a mild or benign form of rheumatoid arthritis. And not everyone with rheumatoid arthritis responds to anti-TNF therapy. Even those who do may find their disease flares up again once therapy is stopped. For these reasons, the experts recommend that anti-TNFs be used only when first-line treatment with methotrexate or some other DMARD fails.

Anti-TNF agents are often used in combination with methotrexate to benefit people with active rheumatoid arthritis whose symptoms don't respond to methotrexate alone. Currently, infliximab, which received its initial FDA approval for treating Crohn's disease, is recommended for use only in combination with methotrexate. It is given intravenously at intervals of four to eight weeks. Adalimumab and etanercept are self-injected, like insulin. Etanercept must be injected once or twice a week, while adalimumab is injected every other week.

Anti-TNF therapy has been associated, though rarely, with long-term neurological side effects, including flare-ups in people with multiple sclerosis. Anti-TNF therapy also should not be taken by people who may have a latent tuberculosis infection or other bacterial infections. Infliximab should not be taken by anyone with congestive heart failure.

Other immune system modulators. In 2005, abatacept (Orencia) was approved for the treatment of rheumatoid arthritis. A co-stimulation modulator, abatacept keeps the immune system from attacking healthy tissues by interfering with T-cell activation. It appears to reduce the signs and symptoms of rheumatoid arthritis, slow structural damage, and improve physical function in people with moderate-to-severe disease who have not responded well to one or more DMARD or anti-TNF therapies. Abatacept is used alone or with DMARDs, but it should not be used with anti-TNF medications because the combination may lead to infections. It is given as an intravenous infusion every four weeks.

The more common side effects with abatacept include headache, upper respiratory tract infection, sore throat, and nausea. Abatacept can also make you more vulnerable to infections (including pneumonia) or make an existing infection worse. It may also cause an allergic reaction in some people.

In 2006, the FDA approved the use of rituximab (Rituxan), a drug originally developed to treat non-Hodgkin's lymphoma, as a new treatment for rheumatoid arthritis. Rituximab, which is given as an intravenous infusion up to twice yearly, targets and helps to destroy B cells thought to become overactive when the immune system malfunctions in rheumatoid arthritis. Rituximab is supposed to be used in combination with methotrexate, and only in people with moderate or severe rheumatoid arthritis whose disease has not responded to one or more anti-TNF therapies.

The most common serious adverse event caused by rituximab is a condition known as lymphopenia (a reduction in the number of lymphocytes, a type of white blood cell). In rare cases, an initial infusion has caused severe skin reaction or death from kidney failure. Other serious reactions have included shortness of breath, lung congestion, abnormal heart rhythm, and low blood pressure. More common side effects during the first infusion include fever, shaking, chills, weakness, nausea, and headache.

A third drug, anakinra (Kineret), inhibits the actions of interleukin-1 (IL-1), an inflammatory chemical. The FDA approved anakinra in November 2001 for the treatment of moderate to severe rheumatoid arthritis in people who were treated with one or more DMARDs without success. Unfortunately, this drug has not lived up to its promise and is used infrequently.

In some cases, corticosteroids or a device that filters the blood may provide further options for someone with rheumatoid arthritis.

Corticosteroids. Corticosteroids, such as prednisone, reduce the body's ability to generate an inflammatory reaction. But long-term use can actually damage the joints and cause other health problems such as osteoporosis, diabetes, increased susceptibility to infections, cataracts, and hypertension.

Today, corticosteroids are used very cautiously. They may be injected directly into a very inflamed joint or taken orally in low doses if other drugs fail to control inflammation. High doses are reserved for rare, life-threatening crises.

Prosorba column. This blood filtration device has been used since the 1990s to treat a rare blood disease; in 1999 it received FDA approval for use in treating rheumatoid arthritis. This device provides an option for people with moderate to severe rheumatoid arthritis who haven't seen improvement with drug therapy. In a process similar to kidney dialysis, blood is removed through an intravenous catheter attached to one of your arms and circulated through a machine that separates blood cells from plasma. The plasma passes through a column holding a protein that binds to and removes substances thought to cause joint pain and swelling (although these substances remain unidentified). The purified plasma is recombined with the blood cells and returned to the circulation through the other arm. It's effective only temporarily and is usually given once a week for 12 weeks.

Surgery for rheumatoid arthritis

Some people with rheumatoid arthritis require surgery to reconstruct or replace a damaged joint. Surgery is usually recommended when drug treatment alone can no longer improve the situation, although the timing of such surgery ? and whether to go ahead with it ? is up to you and your physician. Surgery is usually viewed as a last resort to reduce pain and improve function. One possible exception is hand surgery, as many hand surgeons advocate early surgical intervention to remove inflamed tissue and to help protect the joints and nearby tendons.

Many of the surgical procedures used to repair joints damaged by osteoarthritis are also used in rheumatoid arthritis. The most common surgical procedures for rheumatoid arthritis are arthroscopy, synovectomy (removal of the inflamed tissue that lines the joint), and arthroplasty (joint repair, including joint replacement). The choice depends, in part, on which joints are involved and whether you have any other medical problems. Total joint replacement, most commonly for severe hip or knee arthritis, is a major operation and carries the associated risks (see "Joint reconstruction or replacement").

Slowing the progression of rheumatoid arthritis

Rheumatoid arthritis is a chronic condition, without a cure. For that reason, most people find that it's necessary to combine the drug therapies and surgical options already described with lifestyle changes and supportive services. It's also a good idea to periodically review your balance of drug, surgery, and other management strategies to make sure they still meet your individual needs.

Physical and occupational therapy. When you have rheumatoid arthritis, it's important to pay special attention to the way you move and the way you function in general. Joint pain and generalized symptoms such as fatigue and stiffness can make ordinary activities ? known as activities of daily living ? more challenging, especially during flares. An occupational therapist or physical therapist can offer many suggestions about how to optimize your capacity to manage everyday tasks at home and at work.

These therapists can also provide you with special devices to help conserve your energy and protect your joints. For example, during times when your joints are particularly tender, you can use a splint, brace, sling, elastic bandage, or cane to reduce the pressure on your joints and protect them from further injury. A podiatrist may provide shoe inserts (orthotics), recommend special shoes, or suggest other treatments to reduce pain in your feet and improve your ability to function.

Exercise. To prevent disability and preserve joint function, it's important to develop an exercise routine. It may help to have your health care provider or a physical therapist evaluate the motion of your joints and suggest specific exercises to help maintain your present level of functioning. If you don't actively use a diseased joint because of pain, you may develop muscle atrophy, which can result in loss of muscle strength and endurance.

Isometric exercises, which do not require joint motion, can be especially effective during flares. It is crucial to work with your health care provider to arrive at the right balance between exercise and rest. Never exercise to the point of increased or severe pain.

Diet. Although unscrupulous vendors may claim otherwise, there is no diet known to improve the symptoms of rheumatoid arthritis, and there are no proven dietary supplements that are clearly effective over a long period of time.

Complementary and alternative therapies. A number of alternative therapies have been advocated for rheumatoid arthritis, although most have not been rigorously studied. Researchers are sorting out which complementary approaches work best for people with rheumatoid arthritis (see "Physical and complementary therapies").

Other types of arthritis

Many other types of arthritis exist. The most common ones are discussed below.

Gout

Gout, a painful and potentially debilitating form of arthritis, has afflicted such famed figures as Benjamin Franklin and Henry VIII. Today it affects roughly two million Americans. This disorder develops after tiny, needle-like crystals of uric acid (a biological waste product) accumulate in joints, causing swelling and extreme sensitivity, sometimes to the point where even the slight touch of a sheet is unbearable. The same crystals may cause kidney stones if they accumulate in the kidneys.

Gout usually affects one joint at a time, most often the big toe, but sometimes a knee, ankle, wrist, foot, or finger. If gout persists for many years, uric acid crystals may collect in the joints or tendons and under the skin, forming whitish deposits known as tophi. About 90 percent of people with gout are men older than 40, and African American men are twice as likely as Caucasian men to be affected. Gout tends not to occur in women until at least 10 years after menopause.

For many people, gout develops after a combination of factors contributes to the buildup of excessive levels of uric acid in the body. Abnormally high levels of uric acid may result from a diet that is rich in purines, chemicals that are broken down into uric acid by the body. Purines can be found in anchovies, nuts, and organ foods such as liver, kidney, and sweetbreads. Sometimes, for unknown reasons, the body will produce too much uric acid regardless of diet. Gout can also develop when the kidneys excrete too little uric acid, which can happen in people with some types of kidney disease and in those who drink too much alcohol. In addition, obesity or sudden weight gain can cause elevated levels of uric acid. Some medications, particularly diuretics, also contribute to high uric acid levels. People at risk for developing gout include those with a family history of the disease and those with hypertension, hyperlipidemia, or diabetes.

To reach a diagnosis, your doctor will ask you about your diet, your medication use, your alcohol consumption, and whether you have a family history of gout. During a physical exam, your doctor will inspect your inflamed joints and look for tophi on your skin. Your doctor may also use a needle to withdraw a small fluid sample from your affected joint. This fluid will be examined under a microscope to determine whether uric acid crystals are present. Your doctor may also order a blood test to determine your uric acid level, but this test is not definitive because ? for a variety of different reasons ? many people without gout experience elevated uric acid levels, and even in people with gout, the results may be normal.

Gout is usually treated with a two-prong medication strategy: The first goal is to ease attacks of joint pain and inflammation, while the second, longer-term goal is to decrease blood uric acid level and prevent further attacks.

Usually a doctor begins by prescribing a nonsteroidal anti-inflammatory drug (NSAID) to control pain and inflammation (see "NSAIDs"). Avoid taking aspirin, as it may raise your uric acid level. If you cannot tolerate an NSAID or if these drugs are ineffective, your doctor may suggest a corticosteroid. Much less often, oral colchicine is prescribed, but be aware that this drug tends to cause unpleasant side effects (nausea, vomiting, cramps, diarrhea) and is not well tolerated in about 80 percent of people.

For people with attacks that respond poorly to therapy, involve multiple joints, or occur frequently, or when kidney stones or tophi are present, a second type of drug may be prescribed to prevent future gout attacks. It's important to keep taking this drug even after you feel better. The first choice is usually allopurinol (Aloprim, Zyloprim), which decreases your body's production of uric acid. Other options include probenecid (Benemid) and sulfinpyrazone (Anturane), which help the kidneys to eliminate uric acid. An investigational medication, febuxostat, is not yet approved by the FDA, but has shown promise as a potential new treatment for gout.

You can help prevent further attacks by avoiding diuretics (if your doctors agree), limiting your alcohol intake, drinking plenty of water, and maintaining a healthy weight. You may also want to reduce your consumption of foods that seem to trigger gout attacks, such as meat and certain types of seafood and vegetables ? although many people find that dietary restrictions have few benefits.

Pseudogout

Pseudogout is a form of arthritis that occurs when a particular type of calcium crystal accumulates in the joints. As more of these crystals are deposited in the affected joint, they can cause a reaction that leads to severe pain and swelling. The swelling can be either short-term or long-term and occurs most frequently in the knee, although it can also affect the wrist, shoulder, ankle, elbow, or hand. The pain caused by pseudogout is sometimes so excruciating that it can incapacitate someone for days.

As its name suggests, the symptoms of pseudogout are similar to those of gout (see "Gout"). Pseudogout can also resemble osteoarthritis or rheumatoid arthritis. A correct diagnosis is vital, as untreated pseudogout can lead to joint degeneration and osteoarthritis. Pseudogout is most common in the elderly, occurring in about 3% of people in their 60s and as many as half of people in their 90s.

The cause of this condition is unknown. Because risk increases significantly with age, it is possible that the physical and chemical changes that accompany aging increase susceptibility to pseudogout. Certain medical conditions also make people more susceptible to pseudogout. These include an underactive thyroid (hypothyroidism), a genetic disorder of iron overload (hemochromatosis), or excessive blood levels of calcium (hypercalcemia). Pseudogout also can be triggered by joint injury, such as joint surgery or a sprain, or the stress of a medical illness. If the underlying condition causing pseudogout can be identified and treated, it may be possible to prevent future attacks. Frequently, however, there is no identifiable trigger; in those cases there is no way to prevent pseudogout from recurring.

It may be difficult to diagnose pseudogout because it shares so many symptoms with gout, infection, and other causes of joint inflammation. In fact, pseudogout often occurs in people with other joint problems, such as osteoarthritis. Therefore, even when pseudogout is correctly identified, it is important to investigate whether there are other conditions present as well.

Your doctor may order an x-ray of the inflamed joint in order to look for calcium deposits in the cartilage, although these deposits are sometimes present in healthy elderly people who do not experience the swelling that characterizes pseudogout. To verify the presence of calcium crystals, your doctor may remove a small amount of fluid from the affected joint. This is done with a needle, after applying a numbing medication to the joint. This joint fluid is then analyzed for evidence of calcium crystals, inflammation, or infection. Your doctor may also order tests for other conditions that can trigger pseudogout, including tests of calcium and thyroid function.

To combat joint pain and swelling, your doctor may prescribe NSAIDs such as indomethacin and naproxen, or may give you glucocorticoid injections to keep the swelling down (see "Corticosteroid injections"). Your doctor may also remove fluid from the inflamed joint, a procedure called aspiration, as this may help to ease the pressure and inflammation.

The combination of joint aspiration and medication usually eliminates symptoms within a few days, although the doctor may also recommend treatment with oral corticosteroids over a short period of time. Daily use of a low-dose NSAID or colchicine, a medicine that is also used in the treatment of gout, may help to prevent further attacks. Unfortunately, there is no treatment available that can dissolve the calcium crystal deposits, although the joint degeneration that often goes along with pseudogout may be slowed by treatments that decrease joint swelling. Occasionally, people with recurrent or chronic pseudogout may develop osteoarthritis. In this case, surgery (such as joint replacement) may be the only effective treatment.

Ankylosing spondylitis

Ankylosing spondylitis is a chronic, systemic inflammatory disease that may strike in the prime of life, often between the ages of 20 and 40. It's more common in men than in women. The disease develops as tendons attaching muscles to the spine become inflamed, causing pain and limiting movement. As ankylosing spondylitis progresses, vertebrae in the spinal column may fuse (see Figure 10). In its most advanced stages, the disease may affect joints in the lower back and upper buttocks and also cause inflammation in the eyes, heart, and lungs.

Ankylosing spondylitis runs in some families. An unusually high percentage of people with ankylosing spondylitis ? 96% in one study ? carry the HLA-B27 gene, which occurs more commonly in white people than in other racial groups. A person who carries the HLA-B27 gene has only about a 1%?2% chance of developing ankylosing spondylitis. If a parent or sibling has the condition, however, experts estimate that the risk for a person with the gene rises to 10%?20%. Conversely, not having the gene is no guarantee of protection.

Ankylosing spondylitis is one of the more difficult rheumatic diseases to diagnose early because the symptoms are similar to other causes of low back pain. It may take up to five years after the onset of symptoms for ankylosing spondylitis to show up on an x-ray. At first, x-rays will show that the margins of the sacroiliac joints appear indistinct. Later, the bones ankylose (or fuse).

Most people with ankylosing spondylitis can lead normal lives by using a combination of anti-inflammatory drugs and physical therapy. Your doctor may start by prescribing an NSAID such as indomethacin, but if this doesn't reduce the inflammation, a second choice is often a DMARD such as sulfasalazine or methotrexate. Several studies have demonstrated that anti-TNF agents are beneficial for ankylosing spondylitis. (See Appendix for more information about these drugs.)

If you develop ankylosing spondylitis, you can take steps to prevent spine deformity; in fact, such measures are an essential part of treatment. At least twice a day, try to practice stretching exercises that extend the spine, preferably after a hot shower has reduced stiffness. Rheumatologists recommend swimming as the best overall exercise because it does not stress the back as much as running or other weight-bearing exercises.

Reactive arthritis and Reiter's syndrome

Reactive arthritis gets its name from the fact that symptoms are triggered by some type of infection elsewhere in the body, although the arthritis may develop weeks or months after the original infection. When it does appear, symptoms may flare suddenly, causing pain and stiffness in joints, most typically in the wrists, knees, ankles, and feet.

About 40% of people with reactive arthritis develop conjunctivitis (eye inflammation), which is usually mild and transient. Some people have uveitis, a more serious eye inflammation that may also occur in ankylosing spondylitis. In addition, many people with reactive arthritis develop urinary symptoms due to inflammation of the urethra (the tube that carries urine from the bladder out of the body). When all three problems ? arthritis, eye inflammation, and urinary symptoms ? occur together, the condition is called Reiter's syndrome.

Reactive arthritis and Reiter's syndrome may develop after infection with a sexually transmitted organism, such asone of the primary bacteria that cause a genitourinary infection known as urethritis, once thought to occur almost exclusively in men. Now physicians recognize that women often have genitourinary infections that are initially silent, while men nearly always experience discharge, burning, and other overt symptoms.

Reactive arthritis can also be caused by gastrointestinal infection from bacteria such asorwhich may produce mild transient diarrhea or severe bloody diarrhea accompanied by vomiting. Often food or contaminated water is the source of these bacteria.

Although these infections are common, only certain people seem to be susceptible to developing reactive arthritis, and scientists believe there may be a genetic predisposition. Approximately 70% of white people with reactive arthritis have the HLA-B27 gene, compared with 7% of the general population.

Physicians prescribe antibiotics to alleviate the underlying infection and add NSAIDs for the arthritis. DMARDs such as sulfasalazine or methotrexate may be prescribed for people with prolonged attacks. Relapses occur in about one-third of people.

Psoriatic arthritis

Psoriatic arthritis is a complication of psoriasis, a chronic skin disease that is characterized by bright pink or salmon-colored scales covering the knees, elbows, chest, back, or scalp. While most people with psoriasis do not develop arthritis, around 15% do. About 75% of people develop psoriatic arthritis only after the skin condition appears, although in some people the arthritis occurs before the skin condition.

Psoriatic arthritis usually develops between ages 20 and 50 and can affect any joint of the body. At least five variations of psoriatic arthritis exist, differentiated according to which joints are involved and whether both sides of the body are uniformly affected (such as one elbow or both elbows). When fingernails are affected by psoriasis, becoming pitted and ridged, the joints at the tips of the affected fingers are especially likely to develop arthritis. Psoriatic arthritis affects everyone differently, as symptoms and their intensity may vary and can also change within individuals as time passes. Psoriatic arthritis, like psoriasis, is lifelong and cannot be prevented.

Although the cause of psoriatic arthritis is unknown, it probably develops from a combination of genetic and environmental factors. An estimated 40% of people with psoriatic arthritis have a family history of either arthritis or psoriasis, suggesting some type of genetic predisposition.

It is also likely that certain genes are associated with different kinds of psoriatic arthritis. For instance, the gene HLA-B27 may contribute to psoriatic spondylitis, which affects the spine. Although most people with this gene do not develop psoriatic arthritis, it is found more often in people who develop this condition than in those who do not. Possible environmental factors that could trigger psoriatic arthritis in a genetically vulnerable person include infection and injury. For example, people with HIV are more likely to develop this condition.

Your doctor will ask about your symptoms and do a physical examination. Making a diagnosis may be difficult because symptoms of psoriatic arthritis so closely resemble those of other conditions, such as gout and rheumatoid arthritis. Even x-rays may not always be able to pinpoint psoriatic arthritis as the correct diagnosis. Given the challenges, some people may need to undergo further testing, including x-rays, blood tests, and skin biopsy (a procedure during which a small section of skin is removed for future analysis). Your doctor may also remove a small amount of fluid from your inflamed joints in order to rule out other types of arthritis.

Psoriatic arthritis need only be treated as symptoms arise. However, if psoriatic arthritis is left untreated during symptom flare-ups, it can cause permanent joint damage. Psoriatic arthritis affects each person differently. Although it is only a minor irritation for some, for as many as 25% of people who have it, this condition brings excruciating pain and severe joint damage that can lead to physical disability. Treatment enables most people with psoriatic arthritis to control their pain and to limit joint damage.

Treatment usually begins with taking NSAIDs such as ibuprofen or naproxen to relieve pain and inflammation. If these prove insufficient, your doctor may recommend that you take a DMARD such as methotrexate, which can also improve the psoriasis, or sulfasalazine. When these treatments do not work well, anti-TNF therapies may be particularly effective (see "Biologic response modifiers"). Corticosteroid injections can help to control severe inflammation but are used only occasionally, as they tend to be followed by a flare-up of psoriasis. If severe joint damage occurs, your doctor may recommend surgery to repair or replace those joints. To treat your psoriasis, your doctor may also recommend topical medications that can be applied to your skin or exposure to ultraviolet (UV) light, although these treatments will not help your arthritis. Exercise is also essential, as it helps to keep joints flexible and prevents muscle weakness and loss.

Enteropathic arthritis

Enteropathic arthritis develops in approximately 9%?20% of people with ulcerative colitis or Crohn's disease, which are types of inflammatory bowel disease. These disorders cause episodes of abdominal pain, diarrhea, and weight loss. When arthritis develops in people with ulcerative colitis or Crohn's disease, it usually affects multiple joints in the arms and legs. About 20% of people with enteropathic arthritis have sacroiliitis, an inflammation of the sacroiliac joints in the lowest region of the back.

Studies show that people with enteropathic arthritis have a hereditary disposition to inflammatory bowel disease, but no specific gene has been discovered to account for this type of arthritis. Inflammatory bowel disease causes ulcers and microscopic abscesses in the colon (in ulcerative colitis) or throughout the intestinal tract (in Crohn's disease). Enteropathic arthritis may result from an immune response to intestinal bacteria that gain access to the body through an inflamed bowel.

Your doctor will do a physical examination and ask you about your symptoms and your ulcerative colitis or Crohn's disease. He or she may order imaging and blood tests (see "Diagnosing arthritis").

If you have ulcerative colitis, arthritis often appears during a colitis flare-up and disappears when bowel symptoms subside. It may be difficult to correctly diagnose the type of arthritis in someone with ulcerative colitis, however. Some actually suffer from ankylosing spondylitis, with symptoms that don't fluctuate with colitis symptoms. To further complicate matters, some people diagnosed with ankylosing spondylitis have asymptomatic inflammation of the small intestine, raising the possibility that their disease may actually be enteropathic arthritis.

Physicians treat enteropathic arthritis with medications similar to those used in rheumatoid arthritis, including NSAIDs, sulfasalazine, methotrexate, and anti-TNF medications (see "Medications for rheumatoid arthritis").

Lyme disease and other infectious arthritis

Infectious arthritis, as indicated by its name, is caused by an infection with bacteria, viruses, or fungi. Infections usually spread to the joints from the site of origin by way of the bloodstream, so it may be difficult to determine where the infection started. Once the infection reaches the joint, it can cause warmth, pain, and swelling, sometimes accompanied by fever and chills. Occasionally, infection is introduced directly, as with a puncture wound or major injury.

Infectious arthritis due to bacteria most often affects the knee, although infections that are caused by viruses are most likely to affect small joints like fingers or toes. People with other joint diseases, such as rheumatoid arthritis, are slightly more likely to develop infectious arthritis, although the overall frequency of infectious arthritis, even among people with existing joint problems, is relatively low.

Viruses are the most common cause of infectious arthritis, but bacterial infections tend to be the most serious.

Viral infections. Many viruses may trigger arthritis, including the viruses that cause colds and other respiratory infections, as well as more serious illnesses such as AIDS and hepatitis. Multiple joints can be affected at the same time, and the symptoms sometimes appear similar to those of rheumatoid arthritis. Treating the virus usually alleviates arthritic symptoms, although chronic conditions such as HIV infection and some forms of viral hepatitis can cause ongoing joint pain.

Bacterial infections. Lyme disease, which is caused by the bacteriumis transmitted primarily through bites of deer ticks. An infected person may develop a large, round rash with a central, clear area known as a "bull's-eye," as well as fatigue and other flulike symptoms. But the symptoms may be subtle or mistaken for something else, so Lyme disease may not be diagnosed promptly. If Lyme disease goes untreated and advances, arthritis may develop. This type of arthritis usually affects one or both knees but can also affect other larger joints.

Arthritic joint pain also affects about a third of people with gonorrhea, a sexually transmitted bacterial infection.bacteria, which can cause infections through cuts or breaks in the skin and through contaminated food, can be released in the bloodstream and spread to the knees and other joints, causing intense pain and swelling. If a staph infection is not treated promptly, it can cause serious joint damage within just a few days. Tuberculosis, a bacterial infection that usually affects the lungs, can cause arthritis in the spine and in other large joints, such as the knees or hips. Reactive arthritis and Reiter's syndrome are caused by infection with bacteria in the genitourinary or digestive tracts.

To help determine the infectious agent, your doctor may withdraw a small amount of fluid from the affected joint and have it analyzed. The doctor may also order blood and urine tests. While these tests are unable to pinpoint every infectious agent, blood tests that measure antibodies against some of the more chronic viral diseases, such as hepatitis B, hepatitis C, and HIV, are often helpful.

If you are a woman and a sexually transmitted disease is suspected, the doctor may perform a pelvic exam. If you are a man, your doctor may swab your penis and test your urine.

Any infections should be treated as soon as possible in order to prevent permanent damage. If joint pain and complications have developed, these will be treated separately. You may need to briefly immobilize your affected joint while recovering from the infection. But it's best to become active again as soon as you are able, because exercise and physical therapy can help you regain your strength and mobility.

Treating viral infections. Viral infections do not carry the same risk of joint damage as bacterial infections do, but the infection itself may be harder to treat, as viruses do not respond to antibiotics. Some viral infections, such as HIV or hepatitis C infection, can be treated with antiviral therapy. For other types of viral infections, taking aspirin or ibuprofen can help reduce pain and swelling while the infection runs its course.

Treating bacterial infections. If you have a bacterial infection, your doctor will probably start with an antibiotic. If the infection is advanced or if joint damage has already occurred, the doctor may recommend that you be hospitalized so that your affected joint can be drained (which may require minor surgery) and given adequate rest, and so that you can receive antibiotics intravenously. If your joint is seriously damaged, you may need surgery in order to remove damaged tissue and reconstruct the joint.

It's much better for your health if you can prevent infectious arthritis from developing at all. That means trying to avoid infections, especially those that can cause permanent joint damage. You can reduce exposure to viruses by washing your hands frequently, especially during cold and flu seasons. You can protect yourself from sexually transmitted bacteria and viruses by practicing safe sex. Promptly cleaning wounds and cooking food thoroughly will reduce your exposure to staph infections. To avoid Lyme disease, use tick repellant when walking in the woods or tall grass, wear long-sleeved shirts, and tuck long pants into socks.

Physical and complementary therapies

Despite the variety of medications available for arthritis, physical therapy remains a cornerstone of traditional treatment. In addition, many people with arthritis try various complementary therapies to alleviate pain and other symptoms. Options abound in both these areas and, when carefully chosen, such nonmedical therapies can help you maintain and improve joint function.

Physical therapists focus on restoring or maintaining physical function by designing an individualized treatment program for you. The physical therapist first will thoroughly evaluate your pain, functional ability, strength, and endurance levels, then will provide advice about ways to ease pressure on your joints while building muscles to support them. Physical therapy can take place at a hospital or outpatient clinic, in the therapist's office, or in your home. Some activities can be done alone; others require the therapist's assistance.

You are likely to have much less guidance when it comes to deciding on whether to use complementary therapies, and which ones. Such therapies literally run the gamut from A to Z ? from acupuncture to zinc supplements. And they're popular: One widely cited 1997 paper estimated that one in four people with arthritis used some type of complementary therapy. Although hundreds of such therapies exist, only a few have actually proved to be effective when evaluated in rigorous studies.

To become a wise consumer of complementary therapies, become a skeptical one. Don't buy into any treatment that promises a cure. And be sure to ask questions about complementary therapies: Do the claims rely only on testimonials from people who have tried the treatment, rather than on scientific studies? Are the promises extravagant? Do proponents advise not telling your doctor about the treatment? Do they suggest stopping medical treatment? Are the ingredients unidentified or "secret"? If you answer any of these questions "yes," your best response to trying a therapy is an emphatic "no."

Finally, if you are contemplating any physical or complementary treatment, you should first discuss it with your doctor to make sure it will support, rather than hinder, your arthritis management plan.

Heat and cold therapy

In the 19th and early 20th centuries, wealthy Europeans embraced hydrotherapy (warm baths) and sought cures at exotic spas for real and imagined ailments. Most resorts claimed that the health benefits were from minerals in the water. The therapeutic value actually lay mostly in the water's temperature. Heat raises the pain threshold and relaxes muscles.

Hydrotherapy remains a standard part of the physical therapist's practice, and its techniques can be used at home. A bathtub equipped with water jets or a hot tub can closely duplicate the warm-water massage of whirlpool baths used by professionals. Of course, oversized tubs are expensive luxuries. For most people, the bathtub works nearly as well. A 15?20 minute soak in a warm bath exposes the body to warmth and allows the weight-bearing muscles to relax.

A warm shower can relieve the morning stiffness of ankylosing spondylitis and may help lessen the stiffness caused by other kinds of arthritis. People can upgrade their showers with an adjustable shower-head massager that's inexpensive and easy to install. It should deliver a steady fine spray or a pulsing stream, usually with a few options in between. Therapists also recommend taking a warm shower or bath before exercising to relax joints and muscles. Dress warmly after a shower or bath to prolong the benefit.

A heating pad is another good idea, but keep in mind that moist heat penetrates more deeply. Although you can purchase hot packs and moist/dry heating pads, a homemade hot pack works just as well. Heat a damp folded towel in a microwave oven (usually for about 10?60 seconds, depending on the oven and the towel's thickness) or in an oven set at 300 degrees (for 5?10 minutes ? again, this depends on the oven and towel thickness). To prevent burns, always test the heated towel on the inside of your arm before applying to a joint: It should feel comfortably warm, not hot. To be extra safe, wrap the heated, moist towel in a thin, dry one before placing it on the skin.

Sometimes therapists recommend a paraffin bath. You dip your hands or feet into wax melted in an electric appliance that maintains a safe temperature. After the wax hardens, the therapist wraps the treated area in a plastic sheet and blanket to retain the heat. Treatments generally take about 20 minutes, after which the wax is peeled off. Paraffin bath kits are also available for home use, but it's important to talk with your physical therapist for recommendations and cautions before purchasing one, to avoid burning yourself.

Cold has analgesic effects similar to those of heat: An ice pack on the joint relieves pain, especially after an injury. Gel-filled cold packs are inexpensive and available in different sizes and shapes. Keep two or more in the freezer so you'll have cold therapy available instantly. Ice chips in a plastic bag also work well. Cold packs should be applied for 15?20 minutes and can be reapplied hourly or as needed. Coolant sprays, available from pharmacies, may also be used. Cooling is a temporary measure to relieve pain; too much may induce muscle stiffness and painful circulatory disturbances.

Exercise

Even the healthiest people find it difficult to maintain an exercise regimen. But those with arthritis commonly discover that if they don't exercise regularly, they'll pay the price in pain, stiffness, and fatigue. Regular exercise not only helps maintain joint function, but also relieves stiffness and decreases pain and fatigue. Feeling tired may be partly the result of inflammation and medications, but it's also caused by muscle weakness and poor stamina. If a muscle isn't used, it can lose 3% of its function every day and 30% of its bulk in just a week.

Work with your physician or physical therapist to develop your own exercise program. Most likely this will involve exercises with three goals.

Increase range of motion. These exercises aim to increase the mobility and flexibility of your joints. To increase your range of motion, move a joint as far as it can go and then try to push a little farther. These exercises can be done any time, even when your joints are painful or swollen, as long as you do them gently. For several examples of range-of-motion exercises you can do at home, see Figure 11.

Strengthen your muscles. An excellent way to provide aching joints with more support is to strengthen the muscles surrounding them. Strengthening exercises use resistance to build muscles. You can use your own body weight as resistance. One example: Sit in a chair. Now lean forward and stand by pushing up with your thigh muscles (try to use your arms only for balance). Stand a moment, then sit back down, using your thigh muscles. This simple exercise will help ease the strain on your knees by building up your thigh muscles. Avoid these exercises during arthritis flare-ups.

Build endurance. Aerobic activities such as walking, swimming, and bicycling can all build your heart and lung function, which in turn increases endurance and overall health. Just be careful to pick activities with low impact on your joints. If you have arthritis, you should avoid high-impact activities such as jogging. If you're having a flare-up of symptoms, wait until it subsides before doing endurance exercises.

Joint protection strategies

When you have arthritis, it's important to pay attention to your body's signals. Overuse of arthritic joints can lead to pain, swelling, and additional joint damage. A physical or occupational therapist can teach you how to conserve energy, protect your joints, accomplish daily tasks more easily, and adapt to lifestyle disruptions. Many of these strategies are simple common sense.

Keep moving. Avoid holding one position for too long. When working at a desk, for example, get up and stretch every 15 minutes. Do the same while sitting at home reading or watching television.

Avoid stress. Avoid positions or movements that put extra stress on joints. For example, opening a tight lid can be difficult if you have hand arthritis. One solution is to set the jar on a cloth, lean on the jar with your palm, and turn the lid using a shoulder motion. Better yet, purchase a jar opener that grips the lid, leaving both hands free to turn the jar.

Discover your strength. Use your strongest joints and muscles. To protect finger and wrist joints, push open heavy doors with the side of the arm or shoulder. To reduce hip or knee stress on stairs, lead with the stronger leg going up and the weaker leg going down.

Plan ahead. Simplify life as much as possible. Eliminate unnecessary activities (for example, buy clothing that doesn't need ironing). Organize work and storage areas; store frequently used items within easy reach. Keep duplicate household items in several places; for example, stock the kitchen and all bathrooms with cleaning supplies.

Use labor-saving items. In the kitchen, use electric can openers and mixers. In the bathroom, cut down on scrubbing by using automatic toilet bowl cleaners and spray-on mildew remover in showers or tubs.

Use adaptive aids. Numerous devices on the market can help you avoid unnecessary bending, stooping, or reaching. Long-handled grippers, for example, are designed to grasp and retrieve out-of-reach objects. People with limited movement might have an easier time getting dressed by using long-handled hooks to put on socks and long-handled shoe horns. Also helpful are shoes that slip on or fasten with Velcro, pre-tied neckties, and garments with Velcro fasteners, zippers, or hooks and eyes instead of buttons. Rubber grips are available to help you get a better handle on faucets, pens, toothbrushes, and silverware. Pharmacies, medical supply stores, and online vendors stock a variety of aids for people with arthritis.

Make home modifications. Using casters on furniture can make housecleaning easier. A grab bar mounted over the tub is a necessity for many people, as is a suction mat in the tub to prevent falls. Putting a bathing stool in the tub or shower is a good idea for people who have arthritis in the lower extremities.

Ask for help. Maintaining independence is essential to self-esteem, but independence at all costs is a recipe for disaster. Achieve a balance by educating family members and friends about the disease and the limitations it imposes and enlisting their support. Ask for help with specific tasks.

Other physical therapies

A variety of other physical therapies have been suggested for the pain of arthritis, but the scientific evidence for their effectiveness is scant. If you choose to explore such therapies and find them useful, be sure to continue your conventional therapy and visit your physician regularly.

For example, a technique called diathermy (deep heat) uses electromagnetic waves of different frequencies to deliver heat deep to the tissues. Microwave and ultrasound are the most common wave frequencies used in physical therapy, chiefly to relieve muscle spasm. Microwaves relax muscles, while ultrasound penetrates deeper to reach other soft tissues as well. Diathermy should not be used on actively inflamed joints, and people with pacemakers cannot be treated with microwaves (although ultrasound is safe for such people). Whether diathermy is useful for people with inflammatory arthritis is controversial.

Doctors sometimes recommend transcutaneous electrical nerve stimulation (TENS) for people with chronic pain. TENS works by stimulating large nerve fibers, which theoretically blocks transmission of pain signals from small fibers. Some people with chronic pain from rheumatoid arthritis or osteoarthritis find TENS quite effective. The TENS device consists of a battery pack and electrodes that attach near the painful joint. The battery generates a very low electrical current to the electrodes, producing a pleasant tingling, vibrating, or massaging sensation.

Diet

The idea that a diet, supplement, or vitamin pill could prevent or cure arthritis is very appealing, but as yet there's no scientific evidence of an effective dietary solution for most types of arthritis. Gout, which can be triggered by certain foods, is the notable exception (see "Treating gout").

However, it is important to keep two issues in mind when it comes to diet. The first is that it's important to eat in a way that helps you to maintain a healthy weight, because excess pounds only increase the stress on your joints. To maintain a healthy weight, exercise regularly and eat a diet low in saturated and trans fats and high in vegetables and lean proteins.

Second, there is some evidence that omega-3 fats, found in cold-water fish such as salmon, herring, sardines, and mackerel, may help reduce inflammation. And some early studies have found that consuming such fats on a regular basis can reduce morning stiffness and joint tenderness in people with rheumatoid arthritis. But it's too soon to know whether these results will hold up over time, or whether people can continue the diet without gaining weight ? which would just create other problems. Even so, it may be wise to increase your consumption of omega-3 fats, if only because this type of diet is a good way to reduce your risk of heart disease.

Acupuncture

Many Americans undergo acupuncture treatments to help relieve pain, including the pain of arthritis. Acupuncture, which involves the application of tiny sterile needles to the skin, has been a staple of Chinese medicine for 2,000 years. Acupuncture is based on the belief that qi, or life force, flows along 14 meridians (channels) within the body. A blockage of qi is said to cause illness, while stimulating certain areas along the meridians with fine needles releases qi and restores health. Acupuncture seems to work by releasing endorphins, a natural morphine-like chemical in the nervous system.

Although some people with arthritis find acupuncture treatments relieve their symptoms, results from studies have been inconsistent. However, a randomized controlled study of 570 people with osteoarthritis, published in thein 2004, found improvement in both joint function and pain relief with acupuncture therapy compared with sham therapy ("fake" acupuncture that participants believed was real). There is no proof that acupuncture reduces inflammation in joints. If you do choose to try acupuncture, talk with your doctor first and find a licensed acupuncturist.

Glucosamine and chondroitin

Glucosamine and chondroitin are both chemical components of cartilage, which has raised the hope that supplements containing synthetic versions of these substances might help stop joint destruction and ease arthritis pain. And over the years, some people who have osteoarthritis have claimed to have less pain and stiffness when regularly taking such products.

A major study designed to answer a key question ? whether these supplements relieve pain ? concluded that the answer may depend on the severity of pain you experience. The Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), reported in thein 2006, involved more than 1,500 people with osteoarthritis of the knee. Participants were randomly assigned to take glucosamine hydrochloride alone, chondroitin alone, a glucosamine-chondroitin combination, or the COX-2 inhibitor celecoxib (Celebrex). The study found that, on the whole, glucosamine and chondroitin supplements ? either taken alone or in combination ? provided no more pain relief than a placebo, but that celecoxib did. But the study also revealed that a certain subgroup of people ? those with moderate to severe pain ? did experience greater pain relief by taking the glucosamine-chondroitin combination than those taking a placebo.

To complicate matters further, the GAIT study used glucosamine hydrochloride, which is a different formulation from the glucosamine sulfite that other studies have found effective in relieving osteoarthritis pain. Meanwhile, the answer to a second key question ? whether taking glucosamine and chondroitin supplements will slow the process of cartilage destruction in the joints (as earlier studies have suggested) ? won't be known until the GAIT researchers complete that portion of the study.

At this point, if you're wondering whether you should take glucosamine and chondroitin supplements, the answer is: It depends. If you are experiencing moderate to severe osteoarthritis pain, try the glucosamine-chondroitin combination for two to three months. If you find it eases your pain, keep using it. If not, you might as well save your money. As always, if you choose to take these or any other alternative preparations, be sure to inform your physician.

Living with arthritis

People with arthritis often worry about the possibility of losing mobility, being unable to work, or growing dependent on others. But only a very small percentage of people with arthritis ever become severely disabled. Still, the emotional burdens of arthritis are considerable and may result in stress, anxiety, and depression.

Because living with chronic arthritis can be difficult, many physicians use questionnaires to assess your psychological function. Depression and anxiety are of particular concern.

Your doctor may also ask questions about what type of family and social supports you have available, to determine whether you need additional help. For example, if you live alone and have trouble walking, your doctor may refer you to a social worker who can help arrange for someone to handle shopping and other chores. If you are depressed or have anxiety, you may be referred to a psychiatrist.

Depression. Depression is common in people with chronic diseases. Arthritis specialists have assumed that depression is directly related to the amount of pain and the number of swollen joints a person has, but this isn't always the case. While some people equate a large number of swollen joints with severe disability, those whose favorite pastime is reading or spending time with family might not consider themselves disabled. However, a relatively slight impairment in hand mobility could be devastating for a pianist or artist, and could have a profound emotional impact. Diagnosing and treating depression can be challenging because its symptoms differ from person to person. But effective medications are available, and they often work best in combination with counseling or psychotherapy.

Stress. People with rheumatoid arthritis often report that the disease seems to flare up following stressful events. Because these anecdotes aren't easy to prove scientifically, some doctors have dismissed them. But within the past decade, immunologists have discovered that stress does, in fact, affect immune function. You can help yourself by finding ways to reduce stress.

Sexual intimacy. Arthritis may interfere with sexual intimacy, especially when the hips, knees, or spine are involved. However, even people with severe arthritis can enjoy an active sex life. A flexible attitude often compensates quite well for having a less-than-flexible body. For example, one might experiment with different positions to find the one most comfortable for intercourse; people with hip, knee, or spine arthritis often find it most comfortable when both parties lie on their sides. There are also other mutually gratifying sexual activities besides intercourse.

Many people find that taking an analgesic an hour before sex or having a warm shower lessens muscle and joint stiffness. Rescheduling sexual activity may also help; afternoons may be better if pain and fatigue are worse in the morning, for example.

Appendix: Drugs used to treat arthritis

Glossary

Proteins produced by white blood cells to fight viruses, bacteria, and other foreign invaders.

A foreign protein or carbohydrate complex that causes an immune response.

Tough, rubbery tissue that forms the surface of bones within joints.

A condition caused when an individual's immune system reacts against his or her own organs and tissues.

Inflammation of the bursae, fluid-filled sacs that ease friction between tendons and bones (and tendons and ligaments), causing swelling and pain.

A joint that contains a tough cartilage plate that permits slight movement.

The main structural protein in connective tissue.

The material that holds various body structures together; cartilage, tendons, ligaments, and blood vessels are composed entirely of connective tissue.

Messenger molecules that allow cells to communicate and alter one another's function.

Physical therapy using high-frequency electric current, ultrasound, or microwaves to deliver heat to muscles and ligaments.

Stretchable protein found in connective tissue.

A site where ligaments or tendons attach to bone; plural is entheses.

A protein that regulates chemical changes in other substances.

Fibrous tissue connecting the plates of the skull.

Arthritis caused by uric acid crystals.

A bony growth on the joint nearest the fingertip, caused by osteoarthritis.

A type of receptor on cells involved in recognizing foreign antigens; these receptors are genetically determined, and some are associated with different types of arthritis.

A response to injury or foreign invasion designed to protect the body; the symptoms are heat, redness, swelling, and pain.

Fibrous tissue connecting bones and cartilage.

Lyme disease: An infectious disease transmitted by a tick bite; characterized by rash, flulike symptoms, and inflammation of the heart, nerves, and joints.

A type of white blood cell. B lymphocytes produce antibodies. T lymphocytes destroy abnormal cells and interact with B lymphocytes.

A common skin disease characterized by thickened patches of inflamed red skin; sometimes accompanied by painful joint swelling and stiffness.

Joint problems triggered by bacterial or viral infection elsewhere in the body.

Any one of over 100 disorders that cause inflammation in connective tissues.

An antibody found in about 85% of people with rheumatoid arthritis; also appears in other diseases and sometimes in healthy people.

The branch of medicine devoted to the study and treatment of connective tissue diseases.

An autoimmune disease in which the skin thickens and hardens; sometimes other parts of the body are affected, and joint pain may result.

The most mobile type of joint; found in the shoulders, wrists, fingers, hips, etc.

Inflammation of the synovium.

A thin membrane lining joint capsules that produces synovial fluid.

A tough, fibrous band of tissue that attaches muscle to bone.

Inflammation of a tendon, usually caused by injury, which may restrict movement of the muscle attached to the tendon.

Inflammation of the urethra.

Inflammation of blood vessels.

Resources

Organizations

American Academy of Orthopaedic Surgeons6300 N. River RoadRosemont, IL 60018800-346-2267 (toll free) or 847-823-7186www.aaos.org

This nonprofit organization provides education and services for orthopaedic surgeons and other health professionals. The Web site includes patient information and a doctor referral service.

American College of Rheumatology1800 Century Place, Suite 250Atlanta, GA 30345404-633-3777www.rheumatology.org

This professional organization of physicians, health professionals, and scientists engages in education, research, and advocacy in order to improve the care of people with arthritis and other rheumatic and musculoskeletal diseases. It also offers practice support to health care providers. The Web site includes patient fact sheets.

Arthritis FoundationP.O. Box 7669Atlanta, GA 30357800-568-4045 (toll free)www.arthritis.org

This nonprofit foundation sponsors public education programs and continuing education for professionals, raises money for research, and publishes patient information materials. Local chapters can advise about doctors and sponsor activities such as swimming and self-help classes.

National Institute of Arthritis and Musculoskeletal and Skin DiseasesInformation ClearinghouseNational Institutes of Health1 AMS CircleBethesda, MD 20892877-226-4267 (toll free)www.niams.nih.gov

This federal agency distributes patient and professional education materials about arthritis and rheumatic diseases. Also refers people to other sources of information.

Special Health Reports

Hands: Strategies for strong, pain-free handsBarry P. Simmons, M.D., and Joanne P. Bosch, M.S.P.T., C.H.T., Medical Editors(Harvard Health Publications, 44 pages)

This report covers many common and uncommon hand conditions that can cause pain and other symptoms. It also provides solutions, including exercise, medication, surgery, and more.

Knees and Hips: A troubleshooting guide to knee and hip painScott David Martin, M.D., Medical Editor(Harvard Health Publications, 41 pages)

This report describes the most common knee and hip conditions, including arthritis. It includes the latest information about medical treatments and surgery, including joint replacement options.

Low Back Pain: Healing your aching backJeffrey N. Katz, M.D., M.S., Medical Editor(Harvard Health Publications, 48 pages)

This report explains why low back pain develops and how back problems are diagnosed, and describes treatment strategies ranging from home remedies to advanced surgical techniques.

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