Furosemide-Induced Thrombotic Thrombocytopenic Purpura: A Report of a Rare Case.

Drug-induced immune thrombocytopenia (DITP) refers to drug-dependent, antibody-mediated platelet destruction. Although several drugs have been implicated as the cause of DITP, the most commonly encountered are heparin, sulfonamides, quinine, vancomycin, and beta-lactam antibiotics. However, furosemide has been rarely reported as the cause of thrombocytopenia. We present a unique case of furosemide-induced thrombotic thrombocytopenia in a 64-year-old female referred by her primary care provider for low platelets, rash, and bleeding. She was recently started on oral furosemide for diastolic heart failure two weeks before this presentation. She was admitted to the intensive care unit and was worked up for new-onset thrombocytopenia. Labs revealed anemia, thrombocytopenia, elevated lactate dehydrogenase, and low haptoglobin with normal serum creatinine. Peripheral smear showed schistocytes, low platelets, and ADAMTS13 level was 0.03. The patient was diagnosed with thrombotic thrombocytopenic purpura and treated with steroids, rituximab, and plasmapheresis, which led to rapid recovery of the platelet count to normal. Based on this case report, clinicians should consider furosemide as one of the drugs potentially causing thrombotic thrombocytopenia. Early detection and prompt management can be lifesaving.