Transplant-Associated TMA — RACP Adult Medicine MCQ

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HardHaematologyTransplant-Associated TMARACP Adult Medicine

A 40-year-old man presents with confusion, seizures, and petechial rash 5 days after a bone marrow transplant. His platelet count is 15 × 10⁹/L with schistocytes on blood film. Creatinine is 200 µmol/L. ADAMTS13 activity is 45% (normal). What is the most likely diagnosis?

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Correct answer: A — Transplant-associated thrombotic microangiopathy (TA-TMA)

Transplant-associated TMA occurs post-HSCT and presents with microangiopathic haemolytic anaemia (schistocytes), thrombocytopaenia, and organ damage (renal, CNS). Unlike TTP, ADAMTS13 is usually normal or only mildly reduced in TA-TMA. Complement dysregulation plays a key role. Treatment includes optimising calcineurin inhibitor levels (common trigger), supportive care, and consideration of complement-directed therapy (eculizumab for severe cases). Plasma exchange is generally less effective than in TTP.

Reference: eTG – 2025 – Haematology; EBMT – 2023 – TA-TMA Guidelines