Two patients with TNK2 mutations and late onset infantile spasm

Clinical and electroencephalography characteristics of 41 children with epileptic spasms onset after 1 year of age

The incidence of epileptic spasms (ES) that begin after the first year of life is much lower than that before 1 year of age. The aim of this study was to identify clinical and electroencephalography (EEG) characteristics, etiologies, treatments, and prognoses in pediatric patients with ES onset after 1 year of age. Forty-one children were retrospectively identified in Children's Hospital of Chongqing Medical University between January 1, 2020 and December 1, 2021. ES onset after 1 year of age have diverse presentations. Although most occur in clusters, are symmetrical and flexional, and occur frequently during awakening, some are characterized as isolated and asymmetrical, have a tonic component, and can also occur during sleep. The hypsarrhythmia variants and focal or multifocal discharges occur alternately in the interictal period, and the focal spikes and slow waves predominated in the unilateral temporal or frontotemporal areas. These patients had diverse etiologies, including structural (51.2 % of patients) and genetic (22.0 %) ones, and 11 patients (26.8 %) had an unknown etiology. No patients in our study had an infectious or immune-mediated etiology. Forty-eight percent of patients responded to hydrocortisone and/or adrenocorticotropic hormone. The efficacy of antiepileptic drug therapy was lower in patients who did not receive concurrent steroid therapy. However, ES onset after 1 year of age caused by a tumor, brain malformation, or other focal lesions, may be cured by focal cortical resection despite a lack of clearly localized EEG surface anomalies. Delays in motor, language, and cognitive development, or behavioral problems were observed in all but three patients.