Utility of electroencephalography in toxin-induced seizures

Toxin-induced seizures differ from seizures occurring in epilepsy and have a high rate of complications. Electroencephalography (EEG) is routinely obtained when there is concern for nonconvulsive status epilepticus (NCSE). The purpose of this study was to characterize the typical findings after toxin-induced seizures, assess the rate of epileptiform discharges and NCSE, and identify any changes in management resulting from EEG.

Patients older than 16 years who had an EEG during hospitalization for drug-induced seizure or seizure-like activity were included. We reviewed 10 years of data (2013-2022) across our hospital system (four community hospitals and one academic center). Patients with a history of seizures and those with cardiac arrest prior to EEG were excluded. The primary outcome was incidence of epileptiform discharges on EEG. The secondary outcome was number of antiseizure medications (ASM) added after EEG.

A total of 256 encounters were screened with 83 patient encounters included. A total of 53% (44/83) of EEGs showed some degree of generalized slowing. A total of 2.4% (2/83) of cases had epileptiform activity on EEG. No cases of nonconvulsive status were identified. No ASM was started in the two cases where epileptiform discharges were identified.

During usual care of toxin-induced seizures, epileptiform discharges are uncommon.