- Clinical science
Antiphospholipid syndrome (APS) is an autoimmune disease that increases the risk of thrombosis as a result of procoagulatory antibodies. The condition may be idiopathic or acquired secondary to an underlying disease, such as systemic lupus erythematosus. Circulating antibodies deactivate anticoagulatory proteins and activate platelets, thereby inducing a hypercoagulable state. Typical clinical manifestations include recurring venous and arterial thrombotic events such as deep vein thromboses, strokes, or transient ischemic attacks. A severe complication of APS in women are recurrent miscarriages of healthy fetuses. The condition should be suspected in patients with a history of thrombosis or miscarriages. It is confirmed by detecting serum antiphospholipid antibodies (e.g., lupus anticoagulant, cardiolipin antibodies). Acute thrombotic events are treated with low-molecular-weight heparin and high-dose glucocorticoids to eliminate antibodies. In mild cases, long-term management involves prophylaxis with low dose aspirin; for patients at high risk of thrombotic events, warfarin is the drug of choice.
- Formation of procoagulatory antiphospholipid antibodies
- Induction of a hypercoagulable state → ↑ risk of thrombosis and embolism
APS usually presents with recurring thrombotic events that may affect any organ.
- Pregnancy-related: recurrent miscarriages and premature births
- Capillaries: splinter hemorrhages
- History of
Serology for antiphospholipid antibodies
Lupus anticoagulant (LA): leads to a prolonged aPTT
- Mixing study
- Russell viper venom test
- Anticardiolipin antibodies (aCL) (IgG and IgM): patients with APS often test false positive for syphilis (positive VDRL or RPR), as the antigen used in syphilis tests is cardiolipin.
- Anti-β2-glycoprotein antibodies
- Lupus anticoagulant (LA): leads to a prolonged aPTT
- Hemolysis, leukocytopenia
- Acute management
- Secondary prophylaxis