skip to main content

Ibrutinib Platelet Dysfunction — RACP Adult Medicine MCQ

Instant feedback + full explanation. One question, done properly.

ModerateHaematologyIbrutinib Platelet DysfunctionRACP Adult Medicine

A 65-year-old man with known chronic lymphocytic leukaemia on ibrutinib develops significant bruising and recurrent epistaxis. His platelet count is normal at 180 × 10⁹/L. His INR and APTT are normal. What is the mechanism of ibrutinib-induced bleeding?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Acquired von Willebrand disease

Ibrutinib causes bleeding in 40–50% of patients through platelet dysfunction (NOT thrombocytopaenia or coagulation factor deficiency). Ibrutinib inhibits Bruton's tyrosine kinase not only in B cells but also in platelets, where BTK is involved in collagen receptor (GPVI) signalling, a key pathway for platelet adhesion and aggregation. Standard coagulation tests (INR, APTT, platelet count) are NORMAL. Platelet function testing (PFA-100 or aggregometry) may reveal the defect. Ibrutinib should be withheld 3–7 days before invasive procedures. Concurrent anticoagulation or antiplatelet therapy significantly increases bleeding risk.

Reference: AMH – 2025 – Ibrutinib; eTG – 2025 – Haematology