Antiphospholipid syndrome
Background
- APS definition (need 1 from each category):
- Presence of at least 1 of the following: DVT, arterial thrombosis, or pregnancy morbidity (eg fetal loss, preterm)
- Presence of at least 1 of the following antiphospholipid antibodies (aPL): lupus anticoagulant (LA), anticardiolipin (aCL), β2-glycoprotein-1 (β2-GP-1)
- APS can occur as a primary condition or in setting of underlying disease (eg SLE)
- Lifelong anticoagulation with warfarin, with the following target INRs[1]
Pathophysiology
- Currently accepted theory: Susceptible patients (eg SLE) develop aPL after infection. After development of aPL, “second hit” stress required to develop full-blown APS. aPL affects coagulation by interacting with protein C, annexin V, platelets, proteases, tissue factor, and impairing fibrinolysis
- “Second hit” stressors: smoking, prolonged immobilization, pregnancy, exogenous estrogen, malignancy, nephrotic syndrome, hypertension, hyperlipidemia
Clinical Features
- Thrombocytopenia, increased PT/INR and aPTT
- Microangiopathic Hemolytic Anemia (MAHA)
- DVT/PE
- Fetal loss
- Heart valve disease
- aPL-nephropathy
- Stroke/TIA, other neuro symptoms
- Livedo reticularis
Differential Diagnosis
Microangiopathic Hemolytic Anemia (MAHA)
- Disseminated Intravascular Coagulation (DIC)
- Thrombotic Thrombocytopenic Purpura (TTP)
- Hemolytic Uremic Syndrome (HUS)
- HELLP syndrome
- Heparin-Induced Thrombocytopenia (HIT)
- Hereditary spherocytosis
- Paroxysmal nocturnal hemoglobinuria (PNH)
- Malignant hypertension
- Scleroderma
- Antiphospholipid Syndrome (APS)
- Other medical causes: malignancy, renal allograft rejection, vasculitides like polyarteritis nodosa and Wegener's granulomatosis
- Drugs: chemotherapy; Clopidogrel (Plavix) associated with TTP
- Nonvascular causes: prosthetic valve (more common with mechanical, more common at aortic valve), LVAD, TIPS, coil embolization, patched AV shunt, AVM
Management
- Anticoagulation (unfractionated heparin, LMWH, or warfarin)
- No benefit in treatment or prophylaxis using ASA or plavix
- Add hydroxychloroquine if patient has SLE
- Warfarin contraindicated in pregnancy!
- DOACs (such as rivaroxaban, apixaban, and dabigatran) have not been shown to be effective in APS
- IVIG, plasmapheresis, and steroids have not been proven to be of benefit in APS
Catastrophic APS Treatment
- Treat stress that precipitated catastrophic APS (eg infection), anticoagulation, high dose steroids
- If evidence of microangiopathy (thrombocytopenia, MAHA), add IVIG and plasma exchange to above regimen
Disposition
- Acute complications, admission with hematology consult
Complications
- Catastrophic APS: widespread thrombotic disease with multiorgan failure precipitated by some stress (eg infection)
See Also
- ↑ Movva S et a. Antiphospholipid Syndrome. eMedicine. Mar 24, 2015. http://emedicine.medscape.com/article/333221-treatment.