Case Presentation: A 51-year-old African American female with a past medical history of hypertension, hyperlipidemia, and alcohol use disorder presented with acute onset confusion and difficulty with communication upon awakening preceded by intermittent mild headache for a few weeks. While in the emergency room, the patient experienced a grand mal seizure. The patient was afebrile and labs revealed a severe anion gap metabolic acidosis and an elevated lactate but no leukocytosis or unremarkable procalcitonin level. On exam, the patient was alert and oriented, had a symmetric face, conjugate gaze, and intact extraocular movements. Neurological exam was notable for right-sided pronator drift and very subtle right hemiparesis. Computed tomography (CT) of the brain without contrast showed hypodense masses in the left parietal and right occipital regions initially thought to be metastatic disease with adjacent vasogenic edema. CT angiography of the head and neck did not show any flow limiting arterial stenoses. Magnetic resonance imaging (MRI) of the brain without contrast showed well-circumscribed lesions demonstrating restricted diffusion in the right occipital and left parietal lobes measuring 2 cm with significant surrounding vasogenic edema and regional mass effect without midline shift or herniation favoring diagnosis of cerebral abscess. Neurosurgery was consulted for stereotactic aspiration of the right occipital lobe mass and blood cultures were drawn. The mass aspiration yielded purulent fluid and patient was started on vancomycin, metronidazole, and cefepime empirically; however, this aspiration did not grow anything on culture, so the patient had to go for partial left parietal craniotomy for abscess drainage and washout and was switched to meropenem empirically. This second culture grew Nocardia paucivorans, and the patient was started on trimethoprim-sulfamethoxazole (TMP-SMX) and ceftriaxone.

Discussion: Nocardia paucivorans is a gram-positive bacteria typically associated with pulmonary disease that can, in rare cases, have CNS involvement, such as brain abscesses. Although most patients infected by Nocardia are immunocompromised, a rare subset are immunocompetent, though alcoholism has also been implicated as a risk factor. We present a rare case of an immunocompetent patient who developed a Nocardia paucivorans brain abscess. The infection has been suggested to start through ingestion or direct inoculation, which can lead to hematogenous dissemination and systemic manifestations. TMP-SMX is the recommended treatment for Nocardia infections and has good CNS penetration; however, resistance can be variable, so administering additional antibiotics is prudent. Stereotactic aspiration is often required; however, in more complex cases, open drainage or excision is sometimes warranted.

Conclusions: Brain abscesses in immunocompetent patients may rarely be caused by Nocardia paucivorans and should be aggressively and promptly treated with antibiotics (including TMP-SMX) as well as possibly stereotactic aspiration or open surgery if deemed appropriate.