Free Communications: Child

Abstract

Abstract *YokoOhtsuka, *HodakaOhta, *MikiInutsuka, *KatsuhiroKobayashi, *HarumiYoshinaga, and *EijiOka *Department of Child Neurology, Okayama University Medical School, Okayama, Japan Purpose: To investigate the electroclinical characteristics and treatment of generalized nonconvulsive status epilepticus (NCSE) in childhood. Methods: The subjects were 21 children whose clinical manifestations and EEGs during NCSE were thoroughly analyzed by simultaneous video-EEG-EMG polygraphic recordings. They consisted of seven patients with Lennox–Gastaut syndrome or other generalized epilepsies (group A), 10 patients with myoclonic epilepsies such as Doose syndrome (group B), and four patients with partial epilepsies who transiently showed atypical absence status during their clinical course (group C). We excluded NCSE observed in some specific epileptic syndromes such as severe myoclonic epilepsy in infancy, epilepsy with continuous spike–waves during slow-wave sleep, and related epilepsies. Results: During NCSE, all patients showed decreased alertness or reactivity. Disturbance of mental activity and/or ataxia also was seen in many cases. In addition to these persistent symptoms, all patients showed frequent seizures during NCSE, such as atypical absences, myoclonic seizures, and negative myoclonus. Atypical absences were often seen in all groups of patients. Myoclonic seizures were seen in almost all patients in group B but were rarely seen in groups A and C. EEGs during NCSE were classified into three types: (a) diffuse slow spike–waves, diffuse fast spike–waves and/or diffuse polyspikes–waves intermixed with high-voltage slow waves (SPW type); (b) diffuse high-voltage slow waves intermixed with short bursts of spike–waves (HVS type); and (c) an extremely disorganized pattern in which high-voltage slow waves and seizure discharges were haphazardly intermingled (disorganized type). SPW type was often seen in group A, and HVS type was often seen in group B. Disorganized type was sometimes seen in groups A and B, but no patient in group C showed this type. Regarding treatment, intravenous injections of diazepam (DZP) were tried in almost all patients and were effective on most occasions. However, their effect usually was only transient. We investigated treatments that had more persistent effects for the termination of NCSE. Valproate (VPA) was effective in 10 (50%) of 20 patients; ethosuximide (ESM), in seven (87.5%) of eight; benzodiazepines (BZDs) in six (40%) of 15; and synthetic adrenocorticotropic hormone (ACTH) therapy in four of four patients. ESM was used in combination with VPA in all seven ESM-responsive patients. In two of them, both ESM and VPA were indispensable. In the others, ESM was added to the ineffective previously administered antiepileptic drugs (AEDs) including VPA, and VPA could be decreased thereafter. Conversely, in 14 of 21 patients, simplification of AED therapy seemed to have a favorable effect. Discontinuation or decrease of BZDs was effective in five patients, carbamazepine (CBZ) in four, phenobarbital (PB) and phenytoin (PHT) in three each, and primidone (PRM) and acetazolamide in two each. We also analyzed the relation between seizure type and treatment effect and also the relation between EEG type and treatment effect. Among 16 patients who had atypical absences during NCSE, ESM was effective in six of seven, VPA in seven in 15, BZDs in four of 12, and synthetic ACTH in three of three. Among the 12 patients who showed SPW-type EEGs, ESM was effective in six of seven patients, VPA in four of 12, BZDs in three of nine, and synthetic ACTH in three of three. Among the six patients who showed HVS-type EEGs, VPA was effective in five of five patients and BZDs in two of four. Conclusions: Generalized NCSE observed in various types of childhood epilepsies shared similar clinical and EEG manifestations. ESM was often effective in patients who had atypical absences and SPW-type EEGs. VPA was often effective in patients who had HVS-type EEGs. Simplification of AEDs had a favorable effect in all groups of patients.