One-month-old boy with group B streptococcal meningitis, subdural effusion, and high levels of interleukin-6

Meningitis is associated with elevated levels of inflammatory cytokines in the blood, cerebrospinal fluid (CSF), and subdural fluid. Subdural effusion prolongs fever in patients with meningitis. However, the reason for this remains unclear. A healthy one-month-old boy was admitted after presenting with bacterial meningitis. He was administered meropenem, cefotaxime, and dexamethasone intravenously. On the 3rd day, blood and CSF cultures revealed the presence of Group B Streptococcus from samples collected on day 1. Subsequently, ampicillin and gentamicin replaced the previous combination of antimicrobials used. On the 4th day, brain magnetic resonance imaging with contrast showed bilateral cerebral ventriculitis and left subdural effusion. On the 11th day, since the subdural effusion had worsened, we performed a subdural puncture from the anterior fontanelle. Owing to the prolonged fever, he was intravenously injected immunoglobulin on day 13. He was afebrile on day 23. Antimicrobials were administered for 28 days. Levels of interleukin-6 (IL-6) in the serum and CSF were the highest on the 1st day at 20,600 pg/mL and 170,000 pg/mL, respectively, and decreased upon treatment. IL-6 concentration in the subdural fluid (30,000 pg/mL) was much higher than that in the serum (9 pg/mL) and CSF (2600 pg/mL). To the best of our knowledge, this is the first report on the cytokines in subdural fluid in patients with group B Streptococcal meningitis. Subdural effusion maintained high levels of IL-6 even after the levels in the blood and CSF decreased dramatically. This could explain why subdural effusion prolongs fever in patients with meningitis.