Heparin-induced thrombocytopenia: an uncommon but serious complication of heparin use in renal replacement therapy.

Heparin-induced thrombocytopenia (HIT) is an uncommon but potentially life-threatening complication of heparin therapy. Hemodialysis and hemofiltration patients are regularly exposed to heparin, which is used for extracorporeal anticoagulation. Type II HIT (HIT-II) is the rarer immune-mediated form and is of huge clinical significance. The clinical manifestation of HIT-II is characteristically with venous and arterial thrombotic events. However, systemic and pulmonary reactions have been reported. Type II HIT is due to antibodies to the heparin-platelet factor 4 complex, which induce a cascade of events leading to thrombocytopenia and thrombosis. Nowadays, with increasing availability of functional and immunoassay tests for HIT-associated antibodies, HIT diagnosis can be confirmed more readily. Hence, it is important to rapidly recognize, diagnose, and manage this syndrome early in hemodialysis patients with thrombocytopenia to avoid serious consequences resulting in morbidity and mortality. We report a case of HIT-II manifesting atypically as a "pseudopulmonary embolus" in a hemodialysis patient and discuss the clinical management of HIT.