SLE-Associated Thrombocytopaenia — RACP Adult Medicine MCQ

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ModerateHaematologySLE-Associated ThrombocytopaeniaRACP Adult Medicine

A 35-year-old woman with SLE develops thrombocytopaenia (platelets 35 × 10⁹/L). Direct Coombs test is negative. Blood film shows no schistocytes. Bone marrow biopsy shows adequate megakaryocytes. Anti-platelet antibodies are detected. What is the most likely diagnosis?

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Correct answer: B — ITP secondary to SLE

SLE-associated immune thrombocytopaenia (secondary ITP) occurs in up to 25% of SLE patients. It results from autoimmune destruction of platelets (anti-platelet antibodies) with adequate bone marrow megakaryocytes. The negative Coombs test and absence of haemolysis distinguish it from Evans syndrome (combined AIHA + ITP). Treatment follows SLE management principles: corticosteroids first-line, hydroxychloroquine continuation, and rituximab or IVIg for refractory cases.

Reference: eTG – 2025 – Rheumatology; ASH – 2019 – ITP Guidelines