Medical Health Encyclopedia

Antiphospholipid Syndrome. Between 34 - 42% of patients with SLE have the antiphospholipid syndrome (APS). This is a specific set of conditions related to the presence of autoantibodies called lupus anticoagulant and anticardiolipin. These autoantibodies react against fat molecules called phospholipids, and so are called antiphospholipids. Their actions have complex effects that include causing narrowing and abnormalities of blood vessels.

• Patients who have APS have a very incidence of blood clots, which most often occur in the deep veins in the legs (32%). Blood clotting in turn puts patients at higher risk for stroke (13%) and pulmonary embolism (clots in the lungs) (9%).

This picture shows a red and swollen thigh and leg caused by a blood clot (thrombus) in the deep veins in the groin (ileofemoral veins). Such a clot prevents normal return of blood from the leg to the heart.

• About 22% of patients have thrombocytopenia--a reduction in blood platelets, which can cause bleeding.
• The effects on blood vessels have also been associated with confusion, headaches, and seizures. Leg ulcers can also develop.
• Patients with APS who become pregnant have a high incidence of pregnancy loss, especially in the late term.

Not all patients with APS carry both of the autoantibodies, and they can also wax and wane and so have varying effects. APS also occurs without lupus in about half of patients with the syndrome.

Thrombocytopenia. In thrombocytopenia, antibodies attack blood platelets. In such cases, blood clotting is impaired, which causes bruising and bleeding from the skin, nose, gums, or intestines. (This condition can also occur in APS, but it is not considered to be one of the standard features of the syndrome.)

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Neutropenia. Neutropenia is a drop in the number of white blood cells. Patients with SLE often neutropenia, but the condition is usually harmless unless the reductions are so severe that they leave the patient vulnerable to infections.