Factors contributing to the duration of a single convulsive seizure > 5 minutes were analyzed in 157 children. The medically treated episodes were compared with seizure episodes resolving without treatment (n = 27). Major differences were in age (p = 0.016) and etiology (p = 0.003), and the association between treatment delay and response became significant after 30 minutes when this was analyzed as a single variable (p = 0.003) in Cox regression analysis.

Prolonged convulsive seizures are a common neurological emergency and a potential cause of neuronal damage and functional sequelae. We explored the role of seizure duration and various background factors for neurological sequelae in children with prolonged convulsive seizures. The population-base of this study was all children (age < 16 years) who had been admitted to the Tampere University Hospital, Finland between 1993 and 1999 with convulsive seizures lasting more than 5 minutes. Patients were followed up individually (mean length of follow-up 2 years 1 month, range 0 to 7 years 8 months). All available data on the prolonged seizure episodes and clinical follow-up were analyzed retrospectively by a detailed review of all medical charts and records. In 186 children (94 males, 92 females; mean age 4 years 5 months, SD 3 years 10 months, range 1 month to 15 years 4 months) there were 279 separate convulsive seizure episodes lasting over 5 minutes, yielding an annual incidence of 47.5 out of every 100000 episodes. Seizure aetiology was idiopathic in 26.2% of episodes, febrile in 41.9%, remote symptomatic in 28%, and acute symptomatic in 3.9% of episodes. Mean duration of all seizure episodes was 42.5 minutes (SD 46.1 minutes) and was significantly correlated with the aetiology: shortest in the febrile group (mean 35.4 minutes) and longest in the acute symptomatic group (mean 88.6 minutes; p < 0.001). There was no mortality related directly to these acute seizure episodes. The most common sequela was an onset of epilepsy in 40 children (22%). Permanent neurological sequelae were noted in only four patients (2.2%; mean seizure duration 16 minutes) and non-permanent sequelae in six patients (3.2%; mean seizure duration 38 minutes). Neurological sequelae of prolonged convulsive seizures in children are rare and are related to aetiological factors rather than the duration of a single seizure. The role of acute seizures in the evolution of epilepsy in children remains obscure.

Prolonged convulsive seizures are a common neurological emergency and a potential cause of neuronal damage and functional sequelae. We explored the role of seizure duration and various background factors for neurological sequelae in children with prolonged convulsive seizures. The population‐base of this study was all children (age < 16 years) who had been admitted to the Tampere University Hospital, Finland between 1993 and 1999 with convulsive seizures lasting more than 5 minutes. Patients were followed up individually (mean length of follow‐up 2 years 1 month, range 0 to 7 years 8 months). All available data on the prolonged seizure episodes and clinical follow‐up were analyzed retrospectively by a detailed review of all medical charts and records. In 186 children (94 males, 92 females; mean age 4 years 5 months, SD 3 years 10 months, range 1 month to 15 years 4 months) there were 279 separate convulsive seizure episodes lasting over 5 minutes, yielding an annual incidence of 47.5 out of every 100000 episodes. Seizure aetiology was idiopathic in 26.2% of episodes, febrile in 41.9%, remote symptomatic in 28%, and acute symptomatic in 3.9% of episodes. Mean duration of all seizure episodes was 42.5 minutes (SD 46.1 minutes) and was significantly correlated with the aetiology: shortest in the febrile group (mean 35.4 minutes) and longest in the acute symptomatic group (mean 88.6 minutes; p < 0.001). There was no mortality related directly to these acute seizure episodes. The most common sequela was an onset of epilepsy in 40 children (22%). Permanent neurological sequelae were noted in only four patients (2.2%; mean seizure duration 16 minutes) and non‐permanent sequelae in six patients (3.2%; mean seizure duration 38 minutes). Neurological sequelae of prolonged convulsive seizures in children are rare and are related to aetiological factors rather than the duration of a single seizure. The role of acute seizures in the evolution of epilepsy in children remains obscure.