Does my patient have a life- or limb-threatening thrombocytopenia?

The diagnosis and management of severe thrombocytopenias can be difficult, but is necessary to avoid significant morbidity and mortality. The causes of severe thrombocytopenias, often with a platelet count of less than 10 × 10(9)/L, include heparin-induced thrombocytopenia, the thrombotic microangiopathies, the catastrophic antiphospholipid syndrome, preeclampsia/HELLP, and posttransfusion purpura. This review provides a brief overview of the key clinical features of each of these major clinical entities, and strategies for their diagnostic workup and therapeutic management.