The results of a prospective, multicenter study of 119 children (age 1 month through 5 years) with prolonged febrile seizures (30 min or longer) are reported from Montefiore Medical Center, and Columbia University, New York; Children's Memorial Hospital, Chicago; and other members of the FEBSTAT study group. The median age was 1.3 years; 46% between 1-2 years. Males were 54%. Development was normal in 86%; and definitely abnormal in 8%. A prior FS occurred in 24%. Family history was positive for FS in 25% and for epilepsy in 9%. The mean peak temperature was 103.2F. The cause of the fever was viral in 54%, otitis media (18%), pneumonia (5%), and unknown (14%). Median duration of the FS was 68 min; 24% were >2 hours. A diagnosis of status epilepticus was not recognized in the ED in 21%. Seizures were convulsive in 99%, definitely focal in 48%, generalized in 22%, and partial with secondary generalization in 66%. 
COMMENT. This report represents a preliminary account of a long-term study to include 200 patients with prolonged febrile seizures, and is intended to clarify the relation of the FS to mesial temporal sclerosis and temporal lobe epilepsy. Febrile status epilepticus accounts for 25% of pediatric SE patients. The high incidence of partial seizures might be expected, given the prolonged nature of the seizures in this study. Hippocampal injury is reported especially in patients with a history of prolonged, focal FS. However, inter-rater agreement on focality reached lesser consensus than other features of FS. The high incidence of viral infection is in agreement with most recent FS studies. The results of viral assays will be of interest and important information, as a prelude to future research in viral etiology and antiviral treatment of FS.