Brain Magnetic Resonance Imaging of Infants with Bacterial Meningitis

Objectives: To describe the results of brain magnetic resonance imaging (MRI) of infants with bacterial meningitis and how the findings affected clinical management.

Study Design: This retrospective study included all infants <12 months of age who were hospitalized at Children's Medical Center, Dallas and had culture-confirmed bacterial meningitis and a brain MRI from January 1, 2001 to December 1, 2011. Infants were identified by review of all positive bacterial cultures of cerebrospinal fluid (CSF) from the Children's Medical Center Microbiology Laboratory. Demographic, clinical, laboratory, and neuroimaging data were reviewed. Infants with ventriculoperitoneal shunt or whose CSF culture yielded skin commensals were excluded. A neuroradiologist blinded to clinical information reviewed all MRI studies.

Results: Of the 440 infants who had a positive CSF culture result, 111 (25%) had a pathogen isolated from CSF and were enrolled in the study. Of these, 68% (75/111) had a brain MRI performed during the hospitalization; abnormalities included leptomeningeal enhancement (57%), cerebral infarct (43%), subdural empyema (52%), cerebritis (26%), hydrocephalus (20%), and abscess (11%). By multiple logistic regression analysis, infants with late seizures and an abnormal neurologic examination were more likely to have an abnormal MRI (P < .05). MRI results led to neurosurgical intervention in 23% of infants; a positive bacterial culture of CSF obtained >48 hours after initiation of antibiotic therapy was associated with neurosurgical intervention (P = .01). Fourteen (19%) infants with bacterial meningitis had a normal brain MRI.

Conclusions: Brain MRIs were performed frequently and often were abnormal in infants with bacterial meningitis, leading to changes in clinical management.