Abstracts

Rationale: Current practice parameters recommend routine electroencephalography (EEG) as part of the diagnostic evaluation but there is insufficient evidence to support a recommendation for the use of routine neuroimaging. We review our data on patients presenting to the Children’s National Medical Center with new onset afebrile seizure. Methods: All patients presenting to the Children’s National Medical Center (CNMC) with a new onset afebrile seizure-like event were evaluated prospectively in a standardized critical pathway which included head computed tomography (CT). Evaluation with magnetic resonance imaging (MRI) was based on clinical suspicion of focality. A Microsoft Office Access database was created to track multiple aspects of the clinical presentation and diagnostic evaluation. During an 87 month period (October 2000 to December 2007), 1354 patients were evaluated with the diagnosis of new onset afebrile seizure. CT and MRI findings were categorized as: normal or abnormal including diffuse or focal and clinically significant or nonspecific findings. Results: Of the 1354 children with afebrile new onset seizures, head CT were performed in 1278 (94.4%) and 710 (52.4%) had CT and MRI. Four hundred eighty nine (68.9%) had normal CT had an MRI. Of these 489, 165 (23.7%) with abnormal MRI: 23% had incidental findings in the MRI, 13% had dysplasia, 13% had focal signal , 7% had vascular injuries, 6% had atrophy/encephalomalacia and 6% had mesial temporal sclerosis. Patients with nonspecific CT abnormalities had variable MRI findings. Of 12 patients with focal CT signal abnormality, 5 (41%) patients had vascular abnormalities in MRI (1 had new arterial stroke and 1 with a new venous stroke) and two (16%) had infection. Four patients had abnormal asymmetry on CT scan with 1 (25%) showing dysplasia on MRI. Fourteen patients had cortical atrophy on CT scan and MRI findings were: cortical atrophy in 5 (35%), delayed myelination in 3 (21%) and dysplasia in 1 (7%) Fifty seven (34.5%) children with new onset afebrile seizures with normal exam, normal CT, and normal EEG had abnormal MRI. Conclusions: Our data demonstrate the benefit of MRI neuroimaging in selected patients with normal CT scan presenting with new onset afebrile seizures. Dysplasia was the most common abnormality seen. MRI is more sensitive than CT for clinically relevant pathology. As it is not usually available acutely, it would be useful to determine which patients need a follow up MRI.