Abstracts

Clinical and experimental data suggest that preexisting pathology could have a role in producing febrile seizures that are both focal and prolonged. We undertook a study of children with first febrile seizure to determine whether MRI-detected brain abnormalities were more common among children with a first complex febrile seizure than among those with a first simple febrile seizure. 159 children, aged 6 months to 5 years, with a first febrile seizure were identified in the Pediatric Emergency Department at NY Presbyterian Hospital. MRI examinations were done within one week of the first febrile seizure and included fast spin-echo MR imaging and high-resolution T2-weighted inversion recovery. MRIs were read blind to seizure type and neurological examination. Kappa was 0.65 on repeat readings of 68 scans (95% CI=0.47-0.83). Structural abnormalities were classified as either possible or definite. MRI examination showed no abnormality in 65.6%, possible abnormality in 21.9%, and definite abnormality in 12.5%. Among children with MRI-detected brain abnormalities, 41 (74.5%) had one abnormality, 12 (21.8%) had two abnormalities, 1 (1.8%) had three abnormalities, and 1 (1.8%) had four abnormalities. Complex febrile seizures were not statistically significantly related to MRI abnormalities (OR=1.5, 95% CI=0.8-3.0). In subtypes of complex febrile seizure, MRI abnormalities were associated with focal febrile seizures (OR=3.5 (95% CI=1.5-8.5), prolonged febrile seizure (OR=1.84, 95% CI=0.8-4.2), and both focal and prolonged febrile seizures (OR=5.6, 95% CI=1.7-18.7), but not with repeated febrile seizure (OR=0.9, 95% CI=0.4-2.2). Children with focal and prolonged febrile seizures were 4.2-fold more likely than children with other febrile seizures to have possible abnormalities on MRI (95% CI=1.1-16.5) and 8.3-fold more likely to have a definite abnormality on MRI (95% CI=2.0-34.6) Children with a first febrile seizure that is focal and prolonged are more likely to have MRI-detected brain abnormalities than children with other kinds of first febrile seizures. This relationship must be better elucidated to determine if routine neuroimaging is warranted in this subset of children with febrile seizure, and to examine any developmental consequences. (Supported by a grant from NICHD: R01-HD368867.)