Nocardia farcinica Brain Abscess Mimicking Acute Ischemic Stroke in an Immunocompetent Elderly Patient: A Case Report.

Central nervous system (CNS) infections caused by Nocardia species are rare but potentially life-threatening. Even more unusual is Nocardia infection in immunocompetent patients. Most patients initially present with a primary respiratory or cutaneous infection that may progress to disseminated disease involving the CNS; however, primary CNS infection is rare. Nocardia farcinica is frequently associated with brain abscesses. We report the case of an 81-year-old immunocompetent man who presented with acute focal neurological deficits and seizures, initially managed as an ischemic stroke. Subsequent clinical deterioration and radiological progression led to suspicion of an alternative diagnosis, prompting initiation of empirical broad-spectrum antibiotic therapy for a presumed CNS infection. Definitive identification of N. farcinica was achieved only after neurosurgical biopsy, allowing targeted antimicrobial therapy with subsequent clinical and radiological improvement. This case highlights the diagnostic challenges posed by nocardial brain abscesses, their ability to mimic acute cerebrovascular events, and the importance of early surgical diagnosis and prolonged targeted antimicrobial therapy.