Dr. Perlmutter submitted a perplexing case of a gentleman with a history of metastatic prostate cancer on hormone blockade who presented with subacute progressive nonfocal neurologic symptoms and signs found to have intraparenchymal hypodensities on cross-sectional cranial imaging. While initial concern was raised regarding the possibility of a metastatic tumor as the etiology, the extremely low prevalence of brain metastases (~0.16% ) prompted further evaluation with a brain biopsy which revealed filamentous branching gram positive rods concerning for nocardia.
Some takeaways from Dr. Perlmutter:
- Nocardia is not a part of the normal human biome and so should not be considered a contaminant if grown from body fluid culture
- Most commonly causes pulmonary infections more commonly in immunocompromised individuals though can be seen in immunocompetent as well
- Should be considered on the "Brain/Lung Syndrome" differential
- Symptoms for pulmonary, CNS, and skin infection can be nonspecific; requires a high index of suspicion for diagnosis
- Nocardia meningitis is often missed or diagnosed late/on autopsy (2)
- Evidence is scant regarding surgical resection vs. medical therapy alone for CNS nocardiosis
- Sulfonamides are the background of treatment and often requires IV therapy initially and higher doses in CNS infections. Optimal duration of therapy is unknown and ranges from 1-6 months (3)
- Hatzoglou V, Patel GV, Morris MJ, et al. Brain metastases from prostate cancer: an 11-year analysis in the MRI era with emphasis on imaging characteristics, incidence, and prognosis. J Neuroimaging. 2014;24(2):161-6
- Bross, J. E., & Gordon, G. (1990). Nocardial menigitis: case reports and review. Reviews of infectious diseases, 13(1), 160-165.
- Corti, M. E., & Fioti, M. E. V. (2003). Nocardiosis: a review. International journal of infectious Diseases, 7(4), 243-250.