- 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
Pediatric Imaging 