Approach to Thrombocytopenia.

Thrombocytopenia ranges from benign to life-threatening, requiring a systematic evaluation including history, physical examination, peripheral blood smear review, and targeted laboratory testing. Pseudothrombocytopenia must be excluded. Mechanisms of thrombocytopenia include decreased platelet production, decreased survival, and splenic sequestration. In the inpatient setting, clinicians should consider postoperative thrombocytopenia, heparin-induced thrombocytopenia (HIT), other drug-induced thrombocytopenias, extracorporeal device-related causes, infection, and disseminated intravascular coagulation (DIC). In the outpatient setting, selected causes of thrombocytopenia include immune thrombocytopenia, chronic DIC, thrombotic thrombocytopenic purpura (TTP), and myelodysplastic syndrome, among others. Early recognition and prompt management of life-threatening conditions such as HIT and TTP is critical.