Acute alveolar sarcoidosis presenting with hypoxaemic respiratory failure

Alveolar sarcoidosis is a less commonly seen pulmonary manifestation of the disease. An acute presentation of this radiological pattern with hypoxaemic respiratory failure has been documented only once, four decades ago. A 30-year-old man presented with acute onset of progressive and persistent dyspnoea over 20 days ago with hypoxaemic respiratory failure. Imaging demonstrated mediastinal lymphadenopathy and coalescent parenchymal alveolar opacities having ill-defined margins along with air bronchograms in the mid and lower zones bilaterally, suggestive of alveolar sarcoidosis. A restrictive pattern with a diffusion defect was seen on pulmonary function testing. Bronchoscopic evaluation revealed non-caseating granulomas on histopathology confirming pulmonary sarcoidosis. This was further supported by an elevated serum ACE level and negative Mantoux test. Oral prednisolone elicited a rapid clinical and radiological response. Alveolar sarcoidosis can rarely present acutely with hypoxaemic respiratory failure, which can respond remarkably and expeditiously to appropriate therapy.