Thrombopénie induite par l'héparine de type II : description de quatre observations chez le brûlé grave

Abstract

Heparin-induced thrombocytopenia (HIT) is a dangerous complication of heparin therapy caused by an antibody against heparin / Platelet Factor 4 (PF4) complex. HIT complicates about 2% of treatment with unfractionated heparin (UFH). The aim of the study was to determine the incidence of HIT in a burn center and to report four cases in severely burned patients. HIT was documented in 2.8% of burns treated with UFH administered for antithrombotic prophylaxis and in none of burns receiving low molecular weight heparin (LMWH). All HIT cases occurred after extensive deep burns (mean total body surface area or TBSA was 60 ± 21%) and three cases had above 75% of burn. We suggest that systemic platelet activation after thermal injury and local production of PF4 in the burn wound could participate to development of HIT. The risk is a late diagnosis since thrombosis clinical detection under burned skin is difficult. HIT appears during the first week of UHF treatment at the same time as a unstable period of fluctuating platelets.