II. Pathophysiology
-
Antiphospholipid Antibodies bind cell membrane phospholipids (including vascular endothelium)
- Antibody binding triggers inflammatory and prothrombotic changes
- Increases risk of recurrent thrombosis of any size vessel
- May have no link with Systemic Lupus Erythematosus despite early associations
III. Diagnosis
- Major clinical associations
- Venous thrombosis
- Arterial thrombosis
- Recurrent Pregnancy Loss
- Thrombocytopenia
- Hemolytic Anemia
- Other clinical associations
- Heart Valve abnormality
- Positive Coombs tests
- Livedo Reticularis
- Migraine Headaches
- Leg ulcers
- Myelopathy
- Chorea
- Pulmonary Hypertension
- Avascular necrosis
IV. Labs
- Partial Thromboplastin Time (PTT) prolonged
- Autoantibodies are present in 5% of healthy patients
- Positive Anticardiolipin Antibody (most sensitive test)
- IgG > 20 GPL
- IgM > 20 MPL units
- Possibly IgA positive
- Positive Lupus Anticoagulant (most specific test)
- Anti-B2-Glycoprotein I Autoantibodies
- False Positive VDRL (30-40%)
V. Prevention of thrombotic complications
- Anticoagulation
- Avoid factors predisposing to thrombosis
- Oral Contraceptive use
- Immobility
- Modify atherosclerotic risk factors