The outcome of 71 neurologically normal children after a first complex febrile seizure (CFS) was determined by review of neuroimaging findings, telephone interviews, and medical records, in a prospective study at Columbia University College of Physicians and Surgeons, New York. During the study period March 1999-July 2002, 293 children presented to the ED with a first febrile seizure and of these, 79 (27%) were complex in type. Complex characteristics (focal, multiple episodes in a 24 hour period, and prolonged duration >15 min) were single in 51 (72%), of which 20 were focal, 22 multiple episodes, and 9 prolonged CFS. Twenty had seizures with multiple complex features. Lumbar puncture was performed in 10 (14%) in the ED, and none had meningitis. Emergency cranial CT scans were obtained in the ED for 10 patients (14%), and 13 (18%) patients were admitted. A total of 46 (65%) patients had emergency CT scans in the ED and/or MRI scans within 1 week after the ED visit and were followed prospectively. Outcome was determined by telephone interview within the subsequent 4 to 44 months (median 22.4 months) in 12 (17%) patients and by medical record review in 13 (18%). Of the 71 patients studied, none had intracranial pathology requiring emergency medical or neurosurgical intervention (95% confidence interval: 4%). It is concluded that the risk of emergency intracranial pathology following a CFS is low, and routine emergency neuroimaging in children with first complex febrile seizures is probably unnecessary. [1]

COMMENT. In children presenting with a complex febrile seizure (CFS), each patient must be evaluated clinically to exclude possible meningitis, encephalitis or abscess, and routine neuroimaging in the ED is considered unnecessary. CT scan is not without risk, both from radiation and the need for sedation. Risk factors for subsequent epilepsy in children with FS include the CFS, a family history of epilepsy, and neurodevelopmental abnormality [2, 3]. Earlier studies found that the duration of the FS was the most important determinant of the later development of epilepsy and an abnormal EEG [4, 5]. Neuroimaging should be considered in the individual patient with a CFS that is very prolonged or is followed by a persistent epileptiform abnormality in the EEG.

Risk factors for recurrence of febrile seizures were reported in a study of FS in Southern Chinese children [6]. Factors reaching statistical significance included: 1) earlier age of onset <1.5 years; 2) family history of FS; 3) CFS as first FS; and 4) relatively lower degree of fever (low threshold) with first FS in patients with recurrence vs those with no recurrence. Factors not significant in determining risk of recurrence of FS included sex, family history of epilepsy, and duration of fever during the FS illness. This study confirms the long established theory of height of the fever as a measure of the FS threshold and risk factor for recurrent FS and epilepsy. (See Ped Neur Briefs May 1995 and May 1994).