Atypical progression of Group B Streptococcus infection: Subdural empyema in an adult with diabetes mellitus

Streptococcus agalactiae (Group B Streptococcus, GBS), traditionally associated with neonatal meningitis and urinary tract infections in pregnant women, has emerged as a significant pathogen in non-pregnant adults. A broad spectrum of GBS infections in adults has been reported, including skin and soft tissue infections, bacteremia without a clear source, urinary tract infections, pneumonia, and less commonly, endocarditis, meningitis, or other invasive infections. We report a rare case of subdural empyema following GBS bacteremia in a 74-year-old man with poorly controlled type 2 diabetes mellitus. The patient presented to the outpatient clinic with progressive gait instability persisting for five days, preceded by a resolved headache and diarrhea. On examination, he was febrile but exhibited no nuchal rigidity or focal neurological deficits. He was discharged home, but blood cultures subsequently grew S. agalactiae, prompting emergent hospital admission. Initial neuroimaging, including magnetic resonance imaging (MRI) of the brain, was unremarkable. On hospital day 5, the patient developed worsening altered mental status and right upper limb weakness. A lumbar puncture confirmed GBS meningitis and repeat brain MRI revealed a subdural empyema. The patient underwent surgical drainage and received prolonged antibiotic therapy, resulting in significant clinical improvement. This case underscores the importance of maintaining a high index of suspicion for meningitis and subdural empyema in patients with GBS bacteremia who develop new neurological symptoms, even when initial imaging is unremarkable. Early recognition, repeat neuroimaging, and timely intervention are essential for managing invasive GBS infections and improving patient outcomes.