Heparin‐induced thrombocytopenia with thrombosis in COVID‐19 adult respiratory distress syndrome

Early reports of coronavirus disease 2019 (COVID‐19) clinical features describe a hypercoagulable state, and recent guidelines recommend prophylactic anticoagulation for patients with COVID‐19 with low‐molecular‐weight heparin, but this would be contraindicated in the presence of heparin‐induced thrombocytopenia (HIT). We address the key clinical question whether HIT is also present during COVID‐19. We report 3 cases of thrombocytopenia with antiplatelet factor 4 antibodies among 16 intubated patients with COVID‐19 with adult respiratory distress syndrome, a higher‐than‐expected incidence of 19%. Each patient had evidence of thrombosis (pulmonary embolism, upper extremity venous thromboses, and skin necrosis, respectively). The serotonin release assay confirmed HIT in 1 case, and 2 cases were negative. We believe this is the first reported case of HIT during the COVID‐19 pandemic. Recognition that the thrombocytopenia represented HIT in the confirmed case was delayed. We recommend clinicians monitor platelet counts closely during heparin therapy, with a low threshold to evaluate for HIT.