43-year-old man with chronic alcoholism presented to a rural medical center with a 2-week history of confusion, fever, dyspnea, dizziness, and fatigue associated with diarrhea and hematochezia. Laboratory results were notable for a platelet count of 19 × 109/L, hemoglobin of 5.0 g/dL, hematocrit of 15.1%, white blood cell count of 3.2 × 109/L, a reticulocyte count of 5.9%, mean corpuscular volume of 118 fL, and normal creatinine. A peripheral blood smear was interpreted at the outside facility as having marked schistocytes. A diagnosis of presumed thrombotic thrombocytopenic purpura/hemolytic uremic syndrome was given. Further testing revealed a decreased vitamin B12 level of 93 pg/mL with unremarkable iron studies.
Severe vitamin B12 deficiency mimicking thrombotic thrombocytopenic purpura