Harvard Health A-Z

Ankylosing Spondylitis

What Is It?

Ankylosing spondylitis is a form of arthritis that mainly affects the lower back. It causes inflammation and damage at the joints, and first affects the sacroiliac joints between the spine and the pelvis. It also can affect other areas of the spine and other joints, such as the knee. Eventually, inflamed spinal joints can become fused, or joined together so they can't move independently. The word spondylitis refers to inflammation of the spine; ankylosis means fusion or the melding of two bones into one.

Ankylosing spondylitis is relatively rare. It affects about 1 in 1,000 people. It may run in families, although its cause is not understood. It most commonly strikes otherwise healthy young men. Men get this condition 10 times more often than women. The disorder most often appears between the ages of 20 and 40, but can develop in children.

Symptoms

A person with ankylosing spondylitis commonly will feel pain or stiffness in the lower back, especially in the morning or after periods of inactivity. Usually, back pain begins in the sacroiliac joint and works its way up the lower spine. Eventually, the disorder can affect the entire spine. People can have pain and tenderness in the thighs, hips and other joints of the torso. Knees and ankles can be inflamed as well, although it usually affects no more than three or four joints in the arms and legs.

One feature of ankylosing spondylitis is that stiffness often improves with activity. People who have this disorder may get worse if they do not exercise regularly. Back pain from many other causes tends to worsen with exercise.

As the spine and its supporting structures stiffen, a person may become bent over. Over time, the bones of the spine can fuse or grow together, causing an extremely stiff, rigid backbone called a poker spine. This may make it difficult to take a deep breath because the rigid spine and stiff joints between the ribs and breastbone make it difficult for the chest to expand. In rare cases, inflammation in the lungs or eyes cause shortness of breath, chest pain or reduced vision with red, painful eyes. The pain and rigidity in the lower back can cause problems walking. Almost any movement can become extremely painful.

Other possible symptoms of ankylosing spondylitis include:

• Fatigue

• Fever

• Loss of appetite

• Weight loss

Diagnosis

Your doctor will ask about your symptoms. He or she will examine you and may take X-rays or other imaging tests, such as a computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan, to look for problems in your sacroiliac joints or any other joints that are painful or stiff. Your doctor also may order a blood test to look for a gene called HLA-B27. This gene is found more commonly in people with ankylosing spondylitis than in other people. However, having the HLA-B27 gene does not mean you have or will develop ankylosing spondylitis. Your doctor will diagnose the condition based on a combination of the symptoms, physical examination, blood tests and imaging tests.

Expected Duration

In most cases, ankylosing spondylitis is mild, and may go undiagnosed for years. However, it is a lifelong problem.

Prevention

There is no way to prevent ankylosing spondylitis.

Treatment

The aim of treatment is to reduce joint pain and to prevent, delay or correct any damage or deformities of the spine and other joints.

MedicationsTo reduce pain, stiffness and inflammation, you may be given nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen (Advil, Motrin and others) or naproxen (Aleve). These medications may help to control your pain so that you can continue normal activities and exercise as part of your treatment. If NSAIDs are not enough to control the pain, more powerful medications such as sulfasalazine (Azulfidine) or methotrexate (Folex, Methotrexate LPF, Rheumatrex) may be recommended. However, these medications may cause side effects, and you have to be monitored regularly while you are taking them. For example, people taking methotrexate should have blood tests of liver function every 8 weeks. The injectable medications, etanercept (Enbrel) and infliximab (Remicade) were recently approved for ankylosing spondylitis; another, adalimumab (Humira), may also be effective. Early studies suggest that these drugs may be much more effective than older drugs.

Daily ManagementTreatment usually includes physical therapy and exercise. A physical therapist will develop an exercise routine for you that probably will include range-of-motion and stretching exercises to help the spine remain flexible. Abdominal and back exercises can help you maintain good posture so you are less likely to stoop. Swimming is an especially good exercise because it may be easier to move stiff, painful areas in the water. Biking also tends to be a good exercise for people with ankylosing spondylitis. Avoid any activities that could put too much stress on your back. For example, jogging may cause back pain to become worse because jogging puts more pressure on spinal joints.

Hot baths, heat and massage can help to relieve pain. If you can, sleep on your back on a firm mattress and use a small pillow or none at all.

Because ankylosing spondylitis can affect the bones of the rib cage, your lung capacity can become restricted. Breathing exercises can help to maintain your lung capacity. If you smoke, quitting should be a priority. Even with the best treatment, some people will develop a fused spine, but most people can still function. At some points, a back brace or other devices, such a corset, cane or joint splints, may help. If other organs are involved, such as your heart or eye, you may have to see a specialist, and may need additional treatment and monitoring. For example, a person with ankylosing spondylitis may need a pacemaker if his or her heart is affected.

Surgery Surgery is needed only if the disease has caused nerve damage in the spine or if joint damage is severe.

When To Call A Professional

Contact a health care professional if you have any symptoms of ankylosing spondylitis, especially:

• Back pain and stiffness that gets worse gradually over weeks or months

• Early morning stiffness that improves when you take a warm shower or do light exercise, especially if this symptom lasts for weeks or months

Prognosis

The symptoms of ankylosing spondylitis usually go through periods of improvement and worsening, and these periods can't be predicted. With treatment, symptoms usually can be relieved or controlled so that you can lead a normal, productive life. However, even with treatment, you may develop permanent posture and movement problems.

Additional Info

Arthritis FoundationP.O. Box 7669Atlanta, GA 30357-0669Phone: (404) 872-7100Toll-Free: (800) 283-7800http://www.arthritis.org/

Spondylitis Association of America P. O. Box 5872Sherman Oaks, CA 91413Phone: (818) 981-1616Toll-Free: (800) 777-8189http://www.spondylitis.org

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