Abstracts

Rationale: There are few data regarding the role of neuroimaging in febrile seizures. The aim of this study was to investigate the presenting characteristics of new-onset seizures associated with fever in children and the yield of neuroimaging and lumbar puncture.Methods: Prospective data were obtained from a standardized evaluation and management plan mandated by a clinical care pathway for children with new onset seizures at a tertiary childrens hospital from 2000-2009. Patients with simple febrile seizures were excluded unless there were other factors which prompted hospital admission. Imaging was mandated for all but simple febrile seizures; CSF was performed at physician discretion for concern of CNS infection. Image findings (CT and MRI) and CSF studies were classified and examined in relation to clinical variables.Results: 301 children presented with new-onset seizures associated with fever. Approximately 10% could be classified as simple partial seizures based on the initial clinical features. 55% had more than one seizure, 43% were more than 10 minutes in duration, and 65% were focal. Head CT was obtained on 92%, MRI brain was obtained in 43%, and lumbar puncture was performed in 54%. Seven (3%) had CSF pleocytosis and five (2%) had a specific pathogen identified (Enterovirus, HHV-6, HSV, S. pneumoniae, and Group A streptococcus). MRI brain revealed abnormalities more frequently than did CT (Table 1). MRI findings suggested meningitis or encephalitis in seven patients, five with documented CSF pleocytosis. Initial head CT was normal or incidental in two of these patients. Two others had CSF pleocytosis with a normal CT head and no MRI brain obtained. Overall, findings informing acute medical management were seen in 11% of MRIs (including infection, stroke, and tumor) vs. 4% of head CTs. Furthermore, MRI revealed chronic abnormalities such as migrational defects, tuberous sclerosis, chronic stroke, and leukodystropy more often than head CT. Conclusions: Children presenting with new-onset seizure associated with fever have a low occurrence of CNS infection. MRI brain, when performed, suggested encephalitis or meningitis in all children with CSF pleocytosis and was also useful in demonstrating other acute or chronic findings. CT often did not provide useful information and may be falsely reassuring. Therefore, when neuroimaging is indicated and when MRI is feasible, MRI brain is preferred over head CT.