Simultaneous Infantile Spasms and Focal Seizures: A Rarely Reported Combined Seizure Phenomenon on Video Electroencephalogram (VEEG)

Abstract

Focal seizures (FS) have previously been described before or after infantile spasm (IS) clusters, but FS occurring simultaneously with an IS cluster has been rarely reported in the EEG literature. We present three cases where focal seizures (FS) occurred concurrently during an infantile spasm (IS) cluster on VEEG. On VEEG, onset of IS cluster preceded FS in all three patients; however, patient three was diagnosed with FS prior to the onset of IS. FS duration ranged from 10–90 s and was electrographic-only in two out of the three patients. Unfortunately, the first two patients are now deceased, and for patient two no etiology was ever identified. Currently, patient three is free of spasms as well as seizures but has global developmental delay; no definite etiology has been identified for their presentation. Concurrent FS with IS suggests that the seizure types may be generated in different brain areas with one seizure type potentially triggering the other and is generally reflective of multifocal or diffuse cerebral disease with a poor prognosis as was seen in at least two of our patients. Our three cases of IS where FS occurred concurrently contribute to the limited existing data describing this phenomenon on VEEG.