Harvard Health A-Z

Antiphospholipid Antibody Syndrome

What Is It?

Antiphospholipid antibody syndrome (APS) is a disorder that causes blood clots in the veins or arteries, miscarriages and other problems. The condition can affect any organ, including the lungs, brain, liver, kidneys, eyes, heart and skin. Women with APS can have repeated miscarriages or late-term death of the fetus.

APS probably involves the immune system, although its exact cause is not known. Antibodies are molecules produced by the immune system that normally fight infection. People with APS have antibodies that interact with proteins in the blood and cause the blood to clot more than normal. However, having antiphospholipid antibodies does not necessarily mean that someone will develop symptoms. Up to 8% of normal people without any evidence of APS have the antibodies.

There are two types of APS: primary and secondary. People with primary APS do not have any associated condition. The secondary form is associated with another immune disorder, such as systemic lupus erythematosus (lupus), or with a viral infection. Secondary APS sometimes is thought to be caused by a medication. The most common medication suspected to cause APS is chlorpromazine (Thorazine). A brief form of secondary APS occurs commonly in children following a viral infection.

Symptoms

The symptoms of APS can include any of the following:

• Nervous system ? APS can cause a stroke; involuntary, jerking movements of the arms or legs (chorea); dementia; migraines and other problems of the nervous system. Stroke symptoms include slurred speech or difficulty understanding or forming words, change in vision or weakness on one side of the body. In a form of APS called Sneddon's syndrome, patients have repeated strokes and a lacy purple and white mottling of the skin, called livedo reticularis. Some APS patients develop a syndrome similar to multiple sclerosis. They can have numbness, double vision, and difficulty walking or urinating.

• Heart and blood vessels ? APS can lead to heart attacks, heart valve problems that can mimic bacterial endocarditis, and clots in the upper chambers of the heart. Up to 20% of younger people who have a heart attack have antiphospholipid antibodies. Clots in the veins can cause inflammation of the veins (thrombophlebitis) of the legs with pain in the thigh or calf, swelling of the leg, and sometimes a visible, red, thickened blood vessel.

• Blood cells ? Up to one in four patients with a condition called idiopathic thrombocytopenic purpura (ITP) have antiphospholipid antibodies. Over time, many of these people develop APS. ITP is characterized by a low number of platelets, which help the blood to clot. Patients with ITP and APS may form blood clots or develop bleeding problems, including life-threatening severe bleeding. Also, red blood cells can break down abnormally causing fatigue, dizziness and pale skin, but this is more common in patients with lupus.

• Lung ? Blood clots in the lung can cause chest pain, shortness of breath and rapid breathing. Repeated clots can cause elevated pressure in the blood vessels around the lungs (pulmonary hypertension), which may cause the patient to be constantly short of breath.

• Gastrointestinal ? APS can affect the blood supply to the intestines, causing abdominal pain, fever and blood in the stool. APS can cause a condition called Budd-Chiari, in which a blood clot prevents blood from flowing out of the liver, and the person may experience nausea, vomiting, jaundice (yellow skin) dark urine, pale stool and swelling of the abdomen.

• Kidneys ? Blood clots that affect the kidneys can cause kidney damage and blood in the urine.

• Skin ? APS can cause purple and white mottling of the skin, and repeated sores (ulcers) and bumps (nodules) of the skin. It also can cause tissue in the fingertips to die, a condition called gangrene.

• Eyes ? Veins or arteries in the retina of the eye can be affected, causing blurring or loss of vision.

• Pregnancy ? APS can cause problems for the fetus, such as miscarriage, placental abruption (a partial or complete separation of the placenta from the uterus before the baby is born) and small placenta. It also can cause problems for the pregnant woman, such as stroke or blood clots in the lungs. APS also may be associated with a syndrome of pregnancy known as HELLP ? each letter stands for a part of the syndrome: hemolysis (breakdown of red blood cells), elevated liver tests and low platelets.

Diagnosis

Many of the symptoms that occur with APS are common and do not necessarily mean APS is the cause. However, when blood clots or miscarriages occur for no apparent reason, or when a young person has a heart attack or stroke, the doctor may order tests to detect the presence of antibodies associated with APS.

People with antiphospholipid antibodies may test positive for syphilis even though they do not have the disease.

Expected Duration

Although some people with APS continue to have symptoms off and on throughout their lives, others improve without any repeat episodes. Some people even lose the antibodies associated with the syndrome. This can happen with primary APS, but it is especially common after a viral infection, in women who recently were pregnant, or when a medication suspected to be associated with APS is discontinued.

Prevention

Since the cause of APS is unknown, there is no definite way to prevent it. However, lifestyle changes can reduce the likelihood of blood clots. This includes quitting smoking, increasing physical activity and avoiding medications suspected to increase the risk of blood clots or cause APS.

Treatment

If you have antiphospholipid antibodies but have not had any blood clots or a miscarriage, your doctor may recommend that you take a low-dose aspirin every day. However, aspirin increases the risks of bleeding, so your doctor will have to determine whether the uncertain benefits are worth the risks for you.

For patients with a history of blood clots, doctors usually prescribe a powerful blood thinner called warfarin (Coumadin), which usually has to be taken for life. Patients who take warfarin need to have their blood tested regularly because if the blood is too thin, the risk of bleeding increases, and if it is not thin enough, clotting is more likely.

Another blood thinner called heparin (sold under several brand names), which is given as an injection, may be used before you start taking pills. Heparin also is used for pregnant women, because warfarin is not safe for the developing fetus.

A Woman with APS who is trying to become pregnant after repeated miscarriages may increase the chance of a successful pregnancy if she starts taking heparin injections and low-dose aspirin as soon as the pregnancy is discovered. Treatment is continued until just before delivery. For this purpose, a different form of heparin called enoxaparin (Lovenox) sometimes is used. Other medications used in advanced cases of APS include steroids, immune-suppressing drugs and antiglobulin medications. However, the benefits of these medications have not been proven, and they can cause significant side effects. They are used only for people who are not responding well to blood thinners.

When To Call A Professional

You should contact a health care professional if you have any of the symptoms of APS. You also should call if you have APS and want to become pregnant, or if you have unusual bruising, bleeding or other symptoms of APS.

Prognosis

People with primary APS generally lead normal, healthy lives with proper medication and lifestyle changes. However, some patients will have repeated blood clots despite the best treatments (a condition called catastrophic antiphospholipid antibody syndrome).

People with secondary APS generally will have similar outcomes, but their illnesses and lifespans can be affected by associated conditions.

Additional Info

American College of Rheumatology1800 Century Place, Suite 250Atlanta, GA 30345Phone: (404) 633-3777Fax: (404) 633-1870http://www.rheumatology.org/

National Institute of Arthritis and Musculoskeletal and Skin DiseasesInformation Clearinghouse1 AMS CircleBethesda, MD 20892-3675Phone: (301) 495-4484Toll-Free: (877) 226-4267Fax: (301) 718-6366TTY: (301) 565-2966http://www.niams.nih.gov/

National Organization for Rare Disorders, Inc. P.O. Box 8923New Fairfield, CT 06812-8923Phone: (203) 746-6518Toll-Free: (800) 999-6673Fax: (203) 746-6481http://www.rarediseases.org/

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