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Pulmonary nocardiosis — SCE Respiratory MCQ

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ModerateRespiratory InfectionsPulmonary nocardiosisSCE Respiratory

A 61-year-old man receiving high-dose prednisolone and cyclophosphamide for vasculitis develops fever, cough and multiple pulmonary nodules, one cavitating. Modified acid-fast staining of sputum shows branching filamentous organisms. What is the most likely diagnosis?

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Correct answer: B — Pulmonary nocardiosis

Immunosuppression with cavitating nodules and weakly acid-fast branching filamentous organisms is characteristic of Nocardia. TB is acid-fast but not branching filamentous. Septic emboli and fungal disease can cavitate but the microbiology points to nocardiosis.

Reference: BNF Co-trimoxazole; BTS guidance on opportunistic respiratory infection