The incidence and duration of unconsciousness and delirious behavior in children with febrile seizures were studied at Nagoya University Graduate School of Medicine and other centers in Japan. In 203 patients with 213 consecutive febrile seizures the duration of seizures was less than 5 minutes in 90.2%, duration of unconsciousness was less than 30 min in 93%, and delirious behavior observed in 2% of patients persisted for 10 to 60 minutes. Delirium appeared before the onset of the febrile seizure and resolved after the seizure. Prolonged unconsciousness >30 min, in 7% of patients, was associated with nongeneralized seizures, seizures >5 min duration, or use of intravenous diazepam. 
COMMENT. Prolonged unconsciousness and delirious behavior are rare with febrile seizures. When these symptoms are present, a diagnosis of acute encephalopathy should be considered.
Delirium with febrile myoclonus. Febrile myoclonic episodes in 11 patients, aged 8 months to 11 years, were associated with fear, surprise and shouting in 73%, a past history of febrile convulsion in 18% and febrile delirium in 9%. The outcome for febrile myoclonus was benign and not complicated by afebrile seizures.