Antiphospholipid antibody syndrome (APS) is an autoimmune disease. It is also known as Hughes Syndrome and only affects 2-4% of the population. 30-50% of Lupus sufferers have APS as do 30% of AIDS sufferers. Children can develop APS after viral infections and some medicines have been known to cause APS (Chlorpromazine, procainamide, dilantin and quinidine). It has also been shown that around 50% of migraine patients have APS.
Normally antibodies would be directed by the immune system to an invading foreign body, i.e. a bacterium. These would bind to the foreign particle and cause coagulation or agglutination by clumping the foreign bodies together.
Phospholipids make up the membranes of our cells and if we had antibodies against these then there could be serious trouble. There are three main classes of antibodies associated with APS. These are anti-cardiolipin antibodies, lupus anticoagulant and anti-beta-2-glycoprotein antibody. Other target molecules have been identified but these are the main causes.
There are two clinical forms of APS, primary and secondary. As with all diseases, primary means there is no underlying cause for the syndrome and secondary means there is an underlying cause. For example, systemic lupus erythematosus can cause secondary APS.
Historically, APS was noticed in patients with positive tests for syphilis but no clinical signs of infection.
1952- two patients with systemic lupus erythematosus had an associated clotting disorder.
1957- a link between recurring pregnancy loss and lupus anticoagulant was established
1963- lupus anticoagulant was further described.
1972- the name, lupus anticoagulant, was given.
1983- Dr Graham Hughes described the link between antiphospholipid antibodies (APLA) and venous/arterial thrombosis.
The mechanisms of APS are not entirely clear. As well as their role in membranes, phospholipids play a part in the coagulation cascade. When they are recognised by antibodies, hypercoagulation occurs.
Arterial Disease:-Myocardial Infarctions, Strokes
Neurological Disease:-The underlying cause of which appears to be thrombosis
Ocular Events:-Amaurosis fugax, retinal artery and vein thrombosis
Thrombocytopenia:-Certain APLA will react with activated platelets, leading to Thrombocytopenia.
APS can lead to many problems in pregnancy, miscarriages, preterm labour, low birth-weight and preeclampsia. Insufficient function of the placenta can occur, causing poor growth of the baby and inability of the baby to undergo labour. A very rare APS condition exists, called severe postpartum illness with fever and heart, lung and kidney failure and multiple blood clots.
Diagnosis of APS is by blood tests but these are still very difficult. About 2% of pregnant women will display a positive result without ever having problems during pregnancy so clinical symptoms are required.
Aspirin is used to thin the blood as a treatment for APS. More effective treatment is Warfarin and then Heparin(for patients who 'break-through' warfarin). These are given orally and heparin can be given intravenously. Pre-pregnancy counselling is also advised.