Antiphospholipid Syndrome

What is Antiphospholipid Syndrome?
Antiphospholipid Syndrome is a disorder in which the blood clotting system begins to form blood clots in the veins or arteries without obvious reason. The symptoms of Antiphospholipid Syndrome include blood clots (thromboses) in leg or arm veins and/or arteries; blood clots which travel to the lungs (pulmonary emboli); sudden loss of vision; occasional episodes of numbness, tingling, or weakness in the face or limbs; stroke; seizures; and recurrent miscarriages. All of these symptoms are the result of blood clots occurring in small to medium sized blood vessels. Most people affected with this disorder have only one or two of any of these symptoms. They are however at risk for developing additional symptoms if not treated appropriately or monitored by a physician knowledgeable about the disorder.

What causes the blood to clot too easily in Antiphospholipid Syndrome?
This is a autoimmune disorder. Antibodies are proteins produced by the body's immune system to identify and remove foreign proteins, bacteria and viruses. In a person with antiphospholipid syndrome, antibodies are present in blood, which appear to react with cell membranes, causing the cells to behave as if they have been irritated or stimulated. This disturbs the normally well controlled clotting system. For example, an antibody may interact with a platelet, causing the platelet to release its cellular contents and form a clot. Antibodies also may attach to cells that line blood vessels. This will cause the normally non-reactive surface to appear reactive to passing blood and a clot will form. In both instances, the antibodies are binding to sites on these cells normally occupied by factors in the blood. When these factors can no longer bind to the cells because their sites are occupied by the antibodies, the blood begins to clot more easily.

What causes these antibodies to be formed?
 After being exposed to infections toxins and stress. Sometimes an antibody is made against ones own body or self which can cause damage to tissues or organs. This is termed an "autoimmune" disease. Common autoimmune disorders include systemic lupus erythematosus (SLE), certain types of thyroid disease, rheumatoid arthritis and vasculitis. Patients taking certain medications such as Dilantin, Phenothiazines, or Hydralazine may develop Antiphospholipid Syndrome. Frequently the antiphospholipid antibody will disappear once the medication has been stopped. Antiphospholipid antibodies also may appear for a short time during a viral infection and may disappear soon after the viral infection is completely resolved. Most often, however, antiphospholipid antibodies are found at the time a patient has developed a blood clot and none of the previously mentioned causes can be found.

How is the diagnosis of Antiphospholipid Syndrome made?
There is no one test that can make the diagnosis of antiphospholipid syndrome. Generally, a series of blood tests that look for abnormal blood clotting and antibodies are performed. The Lupus Anticoagulant is a test designed to look for abnormal clotting. The name Lupus Anticoagulant is a misnomer since patients who test positive for a lupus anticoagulant generally have a tendency to clot more easily. The presence of two abnormal test results combined with clinical symptoms makes the diagnosis of Antiphospholipid Syndrome.

How is Antiphospholipid Syndrome treated?
Treatment of Antiphospholipid Syndrome is generally tailored for each patient depending on his or her degree of symptoms. Patients who have had blood clots in the veins or arteries will generally need to receive anti-clotting drugs such as Coumadin or heparin. If clotting is severe, aspirin or a nonsteroidal anti-inflammatory drug may be prescribed in addition to the Coumadin or heparin. If the patient also has an associated autoimmune disorder, other drugs that suppress the immune system such as prednisone or Cytoxan may be required. The length of anticoagulation therapy is highly dependent on the severity of the disorder and the type of blood clotting. In general, a minimum of six months of anticoagulation therapy is needed and some patients require treatment indefinitely.

Asprin can also help and is used to treat the infertility associated with this disorder.

IVIG will take care of those patients in whome the infertility does not respond to asprin.

Are there any clinical conditions where antiphospholipid syndrome requires specialized care?
Yes, during pregnancy. Any woman with antiphospholipid syndrome considering pregnancy is advised to seek high-risk pregnancy advice and to consult a hematologist with knowledge in bleeding disorders prior to becoming pregnant. Patients with a history of recurrent spontaneous abortions may be placed on intravenous (IV) or subcutaneous heparin or oral aspirin during their pregnancy in order to prevent miscarriage due to clotting of the placental blood vessels.

Information provided by the UMHS Hemophilia and Coagulation Disorders Program, February 2003