Pulmonary nocardiosis in West Texas: A case series and literature review

Abstract

Pulmonary nocardiosis is a rare, potentially fatal infection that predominantly affects immunocompromised hosts but is increasingly recognized in patients with chronic lung disease or corticosteroid exposure. Its nonspecific radiographic features often mimic tuberculosis, fungal infection, or malignancy, delaying diagnosis. We present three cases illustrating this diagnostic challenge. A woman with lupus nephritis developed empyema refractory to fibrinolytics and thoracotomy, with cultures eventually growing Nocardia pneumoniae. A man with interstitial lung disease on high-dose steroids presented with a cavitary lesion mimicking mycobacterial disease, later confirmed as nocardiosis on sputum culture. A woman with lupus and post-COVID lung disease developed bilateral cavitary consolidations radiographically suggestive of fungal infection, with negative fungal and viral workup; sputum culture grew Nocardia cyriacigeorgica. All three improved with species-tailored, prolonged antimicrobial therapy. Nocardiosis should remain on the differential for cavitary lung disease unresponsive to standard antibiotics, particularly in immunocompromised or steroid-exposed patients. 

Keywords: Pulmonary nocardiosis, Immunocompromised host, Cavitary lung disease, Chronic lung disease, Empyema, Trimethoprim-sulfamethoxazole.