Coexisting seizures in patients with infantile spasms confirmed by long-term video-electroencephalography monitoring

Abstract

Purpose: We performed this study to evaluate the frequency, types, and ictal electroencephalography (EEG) findings of coexisting seizures in patients with infantile spasms at the onset of spasms. We also evaluated the effect of coexisting seizures on short-term seizure control.

Methods: We retrospectively reviewed the long-term video-EEG and electronic medical records of 109 patients (58 boys and 51 girls) diagnosed with infantile spasms at the Seoul National University Children's Hospital. Coexisting seizure types were classified according to the International League Against Epilepsy seizure and epilepsy classification. Ictal EEG findings were also reviewed. Short-term seizure control rates were compared between groups with or without coexisting seizures.

Results: We identified 27 coexisting seizures in 24 of the 109 patients (22%). The most common type of seizure was generalized tonic seizure followed by myoclonic, focal tonic, tonic-clonic, hypokinetic, and versive seizures. Rates of preterm birth and birth asphyxia were significantly higher in patients with coexisting seizures. Initial anticonvulsant was vigabatrin (103 patients), valproic acid (five patients), and topiramate (one patient). There was no significant difference in short-term seizure freedom (overall seizure-free rates in patients without coexisting seizures vs. those with: 29.2% vs. 11.1% at 2 months, 36.1% vs. 22.2% at 4 months, and 41.7% vs. 27.8% at 6 months). Seizure freedom was significantly lower in the symptomatic groups compared with non-symptomatic groups.

Conclusions: Long-term video-EEG monitoring is required as an initial evaluation in patients with infantile spasms, especially when there are reports of coexisting seizures, or a history of preterm birth or birth asphyxia. Presence of coexisting seizures was not related to poor seizure control in the short-term treatment period.