Prevalence of and Risk Factors for Intracranial Abnormalities in Unprovoked Seizures.

BACKGROUND AND OBJECTIVES Prospective data are lacking to determine which children might benefit from prompt neuroimaging after unprovoked seizures. We aimed to determine the prevalence of, and risk factors for, relevant intracranial abnormalities in children with first, unprovoked seizures. METHODS We conducted a 6-center prospective study in children aged >28 days to 18 years with seemingly unprovoked seizures. Emergency department (ED) clinicians documented clinical findings on a standardized form. Our main outcome was the presence of a clinically relevant intracranial abnormality on computed tomography (CT) or MRI, defined as those that might change management, either emergently, urgently, or nonurgently. RESULTS We enrolled 475 of 625 (76%) eligible patients. Of 354 patients for whom cranial MRI or CT scans were obtained in the ED or within 4 months of the ED visit, 40 (11.3%; 95% confidence interval [CI]: 8.0-14.6%) had clinically relevant intracranial abnormalities, with 3 (0.8%; 95% CI: 0.1-1.8%) having emergent/urgent abnormalities. On logistic regression analysis, a high-risk past medical history (adjusted odds ratio: 9.2; 95% CI: 2.4-35.7) and any focal aspect to the seizure (odds ratio: 2.5; 95% CI: 1.2-5.3) were independently associated with clinically relevant abnormalities. CONCLUSIONS Clinically relevant intracranial abnormalities occur in 11% of children with first, unprovoked seizures. Emergent/urgent abnormalities, however, occur in <1%, suggesting that most children do not require neuroimaging in the ED. Findings on patient history and physical examination identify patients at higher risk of relevant abnormalities.