Fulminant Pneumocystis jirovecii pneumonia presenting as multi-organ dysfunction syndrome in an immunocompetent host.

Present case describes an apparently healthy adult who developed severe Pneumocystis jirovecii pneumonia (PJP) leading to multiple organ dysfunction syndrome. The patient presented with month-long fever, fatiguability and recent onset dyspnoea, subsequently developing acute respiratory distress syndrome (ARDS), acute kidney injury and haematological complications. Definitive diagnosis was made through microscopic examination of P.jirovecii cysts stained by Grocott Gomori Methenamine Silver (GMS) and positive PCR assay of broncho-alveolar lavage fluid. This case highlights the evolving spectrum of PJP manifestations and emphasizes the need for early diagnosis and appropriate management in apparently immunocompetent hosts.