Antiphospholipid syndrome (APS), also known as Hughes syndrome, is a systemic autoimmune condition characterized by the presence of antiphospholipid antibodies (aPL) in the serum of patients with thrombotic events and/or recurrent pregnancy complications.
The exact prevalence of APS is unknown but aPLs are thought to be present in 2-5% of the general population. It is not a rare disease in Europe.
A medical history of headaches or migraines is one of the earliest manifestations of APS. The disease usually starts in young to middle aged adults but it can occur at all ages. Classic signs include thrombosis (most commonly in the deep limb veins) and obstetrical complications (recurrent fetal loss and preeclampsia). Other manifestations include neurological (transient cerebral ischemia and ischemic stroke, memory loss, chorea, seizures and visual disturbances), cardiovascular (coronary artery disease), dermatological (livedo reticularis, skin ulcerations, digital gangrene, splinter hemorrhages), hematological (thrombocytopenia), renal (microvascular thrombosis, renal vein thrombosis, renal artery stenosis) and gastrointestinal (abdominal angina, Budd-Chiari syndrome [see this term]) conditions. Recurrent thromboses are common. If APS occurs with systemic lupus erythematosus (SLE, see this term) then it is referred to as secondary APS. Primary APS is used when no other autoimmune diseases are present. A very rare accelerated form of APS is catastrophic APS. It occurs most frequently in women in their 30s and can lead to massive venous thrombolembolism along with respiratory failure.
Exact etiology is unknown but is thought to be multifactorial. There is, in some families, strong evidence of a genetic component. aPLs are thought to interfere with the function of binding proteins and activate endothelial cells inducing a proinflammatory and procoagulant state in blood vessels which leads to thrombosis.
Diagnosis is based upon clinical and laboratory criteria. Diagnostic classification criteria for APS are vascular thrombosis, pregnancy morbidity (one or more unexplained deaths of morphologically normal fetus beyond the 10th week or one or more premature births before the 34th week of gestation or three or more unexplained consecutive spontaneous abortions before the 10th week of gestation) and the presence of aPLs (anticardiolipin, anti-beta2GPI, lupus anticoagulant).
Differential diagnoses include multiple sclerosis, Sjögren's syndrome, fibromyalgia (see these terms), thyroid disease and factor V Leiden.
Management is intended to prevent thrombosis. Drugs such as aspirin, heparin and warfarin are most commonly prescribed. Warfarin is very effective and safe for those with thrombosis but it is avoided in pregnant women as it can be toxic to the fetus. Clopidogrel can also be effective. Recurrent thrombotic episodes require life-long anticoagulation therapy and pregnant patients with a history of recurrent spontaneous abortion require heparin therapy and low-dose aspirin therapy during most of gestation. There is no cure for APS but lifelong treatment along with taking steps to reduce the risk of thrombosis (eating a healthy diet, exercising, restraining from smoking and avoiding oral contraceptives) can reduce the recurrence of thrombosis.
Without treatment, the disease can be life-threatening. Catastrophic APS has a mortality rate of 50% but is extremely rare. APS is the most common treatable cause of recurrent miscarriage. Pregnant women can be tested for aPLs and if positive, can receive the recommended therapy increasing their chance of a successful pregnancy from 15% to over 90%.
Last update: July 2011