A 34-year-old woman presents with fever, confusion, petechial rash, and oliguria. Hemoglobin is 7.2 g/dL, platelet count 14,000/mm3, LDH markedly elevated, and PT/aPTT are normal. Which peripheral smear finding is central to confirming the diagnosis?

• A Hypersegmented neutrophils
• B Schistocytes ✓
• C Bite cells with Heinz bodies
• D Rouleaux formation

Explanation

The pentad features suggest thrombotic thrombocytopenic purpura, a thrombotic microangiopathy. Red cells are sheared by fibrin strands in occluded microvessels, producing schistocytes, helmet cells, and triangular fragments on the smear. Schistocytes also occur in DIC, malignant hypertension, and mechanical valves, so they confirm microangiopathic hemolysis rather than one specific entity. Hypersegmented neutrophils indicate megaloblastic anemia, bite cells indicate oxidant hemolysis in G6PD deficiency, and rouleaux indicates hyperproteinemia such as myeloma.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.