Lupus Anticoagulant
From Anvita Health Wiki
Contents |
More Specific Terms
- hexagonal phospholipid neutralization test
- neutralization dilute phospholipid in plasma
- neutralization platelet in plasma
Etiology
- lupus erythematosus (30%) & other autoimmune disorders
- infections
- lymphoproliferative disorders
Epidemiology
- found in 2% of normal individuals
Pathology
-
- antibodies to cardiolipin may be present
- prolonged PTT ( in vitro phenomenon)
- confers hypercoagulable state in vivo
- predisposes to arterial & venous thrombosis
- possible mechanisms
- interference with anticoagulant activity of protein C
- activation of platelets
- inhibition of PGI2 production by endothelial cells
Laboratory
- lupus anticoagulant may be suspected when a prolonged PTT is not correcting by mixing the patient's plasma 50:50 with control plasma (indicating an inhibitor of in vitro anticoagulation)
- presence of lupus anticoagulant is confirmed by:
- comparing the PTT of the patient's plasma to control plasma in the presence of a dilute solution of phospholipids
- dilute Russell's viper venom clotting time
- abnormal aPTT is corrected by substituting activated or resting platelets for exogenous phospholipid
- hexagonal phospholipid neutralization test is useful when the patient is anticoagulated with heparin or warfarin
Management
More General Terms
Additional Terms
References
- Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 384, 396
- Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
- Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996, pg 738
