IDCases | 2021
New-onset seizures and a tangled up Gram’s stain: Actinomyces brain abscess
Abstract
A 62-year-old male with a past medical history of diabetes mellitus presents to the Emergency Department for evaluation of new-onset generalized tonic-clonic seizures resulting in tongue bite and minor trauma. Upon arrival, he was confused and agitated and unable to provide any further history. Initial laboratory workup revealed a leukocytosis of 11.2 cells/mL (normal 3.4–9.6 cells/mL), with 83 % neutrophils. Head magnetic resonance imaging with intravenous contrast revealed a left parietal lobe ring-enhancing lesion in the grey-white matter junction measuring 1.3 cm with associated surrounding edema concerning for brain abscess. Blood cultures were obtained, and the patient was started empirically on cefepime, metronidazole, and vancomycin. A stereotactic brain biopsy was performed and showed grampositive cocci, Gram-negative cocci and beaded branching Gram-positive bacilli, with a negative modified acid-fast staining (Figs. 1 and 2). The cultures grew Actinomyces georgiae, Streptococcus intermedius, Streptococcus mitis, and Staphylococcus epidermidis. The initial presentation of our case is consistent with brain actinomycosis in a patient with diabetes resulting in seizures. Actinomycosis is an invasive infection due to bacteria in the genus Actinomyces, which consist of filamentous non-sporeforming, anaerobic, Gram-positive commensal bacteria found in the human mouth, gastrointestinal tract, and ubiquitously in the soil. Actinomyces georgiae has mainly been described as normal oral microbiota in healthy humans. The presence of other “companion pathogens” that facilitate Actinomyces virulence, such as Streptococcus spp. and coagulase-negative staphylococci is commonly described in actinomycosis (65–95 %), as seen in our patient [1]. Actinomycosis of the central nervous system (CNS) is rare and most likely results from hematogenous or contiguous infection. CNS involvement of Actinomyces sp. may include meningitis or meningoencephalitis, actinomycoma, subdural empyema, epidural abscess, and single or multiple brain abscesses. Several cases have