A 59-year-old female who had been diagnosed with multiple myeloma received treatment with bortezomib and dexamethasone. Subsequently, she underwent autologous peripheral stem cell transplantation. Two months later she was admitted with a urinary tract infection complicated by Klebsiella bacteremia. Her complete blood count showed anemia (8.5 g/dL), thrombocytopenia (22 K/uL), increased reticulocytes, and normal white blood cells (8.9 K/uL). The peripheral blood smear (panel A) revealed moderate schistocytosis. The LDH was 2920 IU/L, haptoglobin was undetectable, D-dimer was 2020, fibrinogen was 375, and ADAMTS13 activity was low.

Acute renal failure ensued that required hemodialysis. A kidney biopsy showed thrombotic microangiopathic nephropathy (panel B; arrow shows a thrombus). A diagnosis of thrombotic thrombocytopenic purpura (TTP) was made and plasmapheresis was started with resolution of TTP over the next few weeks. Although schistocytes are a clue to disseminated intravascular coagulopathy, malignancy, anatomic vascular abnormalities, hypertension, and connective tissue disease among others, they were indicative of TTP in this patient.