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1. ANTIPHOSPHOLIPID SYNDROME
SIVASUBRAMANIYAN RAJAVEL
1627

2. • Antiphospholipid syndrome (APS) is an autoimmune phenomenon
that presents with thrombotic events and/or adverse pregnancy
outcomes related to the presence of persistent antiphospholipid
antibodies (aPL), which produce a hypercoagulable state.
• aPL: autoantibodies directed against
phospholipid-binding proteins
• Primary APS: APS occurring due to isolated
aPLs
• Secondary APS: APS occurring in the setting
• of underlying systemic autoimmune disease

3. CLASSIFICATION OF APS

4. ETIOLOGY
Primary (50%):
• Genetic predisposition to develop antibodies
• Due to mutations in HLA-DR7, DR4, DQw7, and/or C4
Secondary (50%):
• Systemic lupus erythematosus (SLE) (most common, 35%)
• Rheumatoid arthritis (RA)
• Sjögren syndrome (SS)
• Immune thrombocytopenic purpura (ITP)
• HIV
• Hepatitis C virus (HCV)

5. CLINICAL MANIFESTATIONS
• Deep vein thrombosis (DVT):
• DVTs of the lower extremities (most common DVTs):
• Unilateral swelling and/or pain in the extremity
• Pain with dorsiflexion of the foot
• Pulmonary embolism (PE):
• Dyspnea
• Acute respiratory distress
• Pulmonary hypertension
• Cerebral sinus thrombosis
• Hepatic and portal vein thrombosis
• Renal vein thrombosis
• Adrenal vein thrombosis
• Superficial vein thrombosis
• Arterial thrombosis:
• Stroke (most common arterial thrombosis)
And transient ischemic attacks (TIAs):
• Focal neurologic findings
• Cognitive deficits
• MI:
• Chest pain
• Dyspnea on exertion
• Retinal thrombosis
• Nephropathy due to vaso-occlusion in the small renal vessels:
• Renal failure
• Proteinuria
• Hypertension
• Recurrent thromboembolic events
Obstetric presentations
Recurrent miscarriages
Preterm delivery of an anatomically
normal infant < 34 weeks gestation
due to either:
Severe preeclampsia or eclampsia
Features consistent with placental
insufficiency:
Oligohydramnios (low amniotic fluid)
Low birth weight
Non-reassuring or abnormal fetal
surveillance testing (e.g., non-stress
tests, biophysical profile, Doppler
studies)

6. DIAGNOSTIC CRITERIA

7. MANAGEMENT
Thrombotic and obstetric APS:
• Initiate anticoagulation with heparin overlapped with warfarin (note: warfarin is contraindicated in pregnancy).
• Low-molecular-weight heparins (LMWHs) are typically the drug of choice.
• Heparins are continued until the INR is in the therapeutic range for 2 consecutive days.
• Heparins can then be discontinued, while warfarin is continued indefinitely for ongoing prophylaxis.
Catastrophic APS:
• Anticoagulation
• IV glucocorticoids
• Plasmapheresis
• IV immunoglobulins (IVIG)
• Arterial thrombosis (e.g., MI, stroke): managed the same as patients without APS

8. PREVENTION OF THROMBOSIS
• Smoking cessation
• Avoiding estrogen-containing contraceptives
• Managing hyperlipidemia/hypertension
• For patients who have never had a thrombotic event (i.e., primary prevention):
• Consider low-dose aspirin (evidence is limited; consider entire clinical picture).
• Optimize modifiable risk factors.
• For patients with a history of thrombosis:
• In patients who do not desire pregnancy: warfarin therapy
• In patients who do desire pregnancy: LMWH and aspirin (warfarin is teratogenic)
• For patients with aPLs but who do not meet diagnostic criteria for APS, antithrombotic medication is not
recommended.