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TTP — RACP Adult Medicine MCQ

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ModerateHaematologyTTPRACP Adult Medicine

A 35-year-old woman presents with petechiae, confusion, fever (39°C), renal impairment (creatinine 180 μmol/L), and jaundice. Platelets 15 × 10⁹/L. Blood film shows schistocytes. LDH is markedly elevated. Haptoglobin is undetectable. Coagulation is NORMAL (PT/APTT/fibrinogen). ADAMTS13 activity is <5%. What is the most likely diagnosis?

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Correct answer: C — Thrombotic thrombocytopenic purpura

Thrombocytopenia with MAHA (schistocytes, elevated LDH, low haptoglobin), fever, renal impairment, and neurological involvement (confusion) with NORMAL coagulation and ADAMTS13 <10% is TTP. Normal coagulation distinguishes from DIC (which has prolonged PT/APTT and low fibrinogen). ADAMTS13 <10% is diagnostic. Treatment: urgent plasma exchange (removes anti-ADAMTS13 antibodies and replaces enzyme), caplacizumab (anti-VWF), and corticosteroids. DO NOT transfuse platelets.

Reference: BSH – 2024 – TTP; ISTH 2025 TTP