Severe Rifampicin-Induced Immune Thrombocytopenia During Treatment of Cavitary Pulmonary Tuberculosis: A Case Report

Rifampicin is first-line therapy for drug-susceptible tuberculosis (TB) but rarely causes severe immune-mediated thrombocytopenia, which may be overlooked amid multiple concomitant medications. A 49-year-old man with cavitary pulmonary TB developed severe thrombocytopenia nine days after starting rifampicin-containing therapy; platelets fell abruptly from 311,000/μL to 9,000/μL. He also received prophylactic heparin, vancomycin, and other antimicrobials. The 4Ts score indicated low probability of heparin-induced thrombocytopenia, and peripheral smear excluded microangiopathic processes. Rifampicin-induced immune thrombocytopenia (RIT) was diagnosed based on temporal association, exclusion of major alternatives, and rapid platelet recovery after rifampicin discontinuation. RIT should be considered in acute severe thrombocytopenia during TB treatment, even with other thrombocytopenia- associated drugs. Early recognition and prompt withdrawal of the offending agent are essential to reduce bleeding risk and permit continuation of effective TB therapy with an alternative regimen.