Overview
Definition
An autoimmune hypercoagulable state characterized by recurrent arterial or venous thromboses and/or pregnancy complications, in the presence of persistent antiphospholipid antibodies.
Epidemiology
Can be primary or secondary (associated with Systemic Lupus Erythematosus in 20-30% of cases). Primarily affects young women.
Etiology & Risk Factors
- Autoantibodies directed against phospholipid-binding proteins (primarily beta-2 glycoprotein I), causing endothelial activation, platelet aggregation, and hypercoagulability
Clinical Symptoms
- Venous thrombosis (DVT, PE)
- Arterial thrombosis (Stroke, TIA, myocardial infarction at young age)
- Pregnancy loss (recurrent embryonic losses before 10 weeks, or unexplained fetal death after 10 weeks, or premature birth due to preeclampsia/placental insufficiency)
- Livedo reticularis / Thrombocytopenia
Clinical Approach
Diagnosis
- Clinical criteria (thrombosis or pregnancy criteria) + Laboratory confirmation of at least one antibody on two separate occasions at least 12 weeks apart: Lupus Anticoagulant, Anti-cardiolipin IgG/IgM, or Anti-beta-2 glycoprotein I IgG/IgM
- *Note: Lupus anticoagulant paradoxically prolongs aPTT in vitro but causes thrombosis in vivo*
Management
- Acute thrombosis: Standard anticoagulation (LMWH bridged to Warfarin)
- Chronic: Long-term therapeutic Warfarin (DOACs are not recommended, especially for triple-positive patients)
- Low-dose Aspirin + LMWH during pregnancy for obstetric APS
Complications
- Catastrophic Antiphospholipid Syndrome (CAPS: rapid microvascular thrombosis causing multiorgan failure; high mortality)
- Recurrent strokes
- Fetal loss