Meningitis / Cerebritis / Intracranial Abscess

• Etiology: organisms responsible
  — Neonates – Group B streptococcus (most common), Escherichia coli, Enterobacter, Citrobacter
  — Infants – Streptococcus pneumoniae (most common), Neiseria meningitidis, Haemophilus influenzae
  — Children – Neiseria meningitidis
• MRI:
  — Meningitis – lack of sulcal suppression / CSF non suppressed on FLAIR and thickened enhancing meninges
  — Abscess – T2 hypointensity – think / smooth enhancing ring due to hemorrhage + paramagnetic free radicals in macrophages / enhancing ring / restricted diffusion = pus
• Complications: communicating hydrocephalus due to obstruction at arachnoid villi -> transependymal flow
• Clinical: subdural effusion during treatment of meningitis does not necessarily mean treatment failure

Cases of Meningitis / Cerebritis / Abscess