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Pulmonary Nocardiosis — SCE Infectious Diseases MCQ

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ModerateImmunocompromised HostPulmonary NocardiosisSCE Infectious Diseases

A 60-year-old man with long-standing rheumatoid arthritis on Methotrexate 15 mg weekly develops pneumonia. Sputum culture grows Nocardia asteroides complex. CT chest shows multiple nodules with early cavitation. What is the first-line treatment?

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Correct answer: E — IV then oral Co-trimoxazole (high dose: 15 mg/kg/day of trimethoprim component initially) for 6–12 months

Nocardiosis in immunosuppressed patients (Methotrexate) presents as pulmonary disease mimicking TB or malignancy. Nocardia is partially acid-fast (distinguishing it from Actinomyces) and aerobic. Co-trimoxazole is first-line treatment at high dose (Trimethoprim component 15 mg/kg/day initially). Treatment duration is prolonged: 6–12 months for pulmonary disease, and longer for CNS involvement. Brain imaging should be performed even in asymptomatic patients as CNS dissemination occurs in ~30% of cases. Alternatives include Carbapenems, Amikacin, and Linezolid.

Reference: BSAC 2022 – Nocardiosis; BTS 2023 – Pulmonary nocardiosis