Purpose: To report an unrecognized EEG pattern occurring in patients with coma with nonconvulsive status epilepticus (NCSE) treated with thiopental and characterized by a high amplitude generalized sharp wave that was induced by isolated or repetitive low frequency photic or tactile stimulation (stimulus-induced generalized epileptiform discharges).
Methods: Review of clinical and EEG records of 4 patients with stimulus-induced generalized epileptiform discharges identified among patients admitted to an intensive care unit (ICU) of our institution who underwent EEG monitoring between July 2011 and January 2013.
Results: Four patients had refractory NCSE secondary to hepatic encephalopathy, brain tumor, immunomediated encephalopathy, or anti-NMDA encephalitis. All of them were treated with several antiepileptic drugs and anesthetics, but stimulus-induced generalized epileptiform discharges were only recorded after control of NCSE with thiopental. The discharges occurred without associated clinical manifestations. Two patients died in the ICU, and two had a favorable outcome. Stimulus-induced generalized epileptiform discharges were not recorded in 240 critically ill patients admitted to the ICU who had an EEG recorded during this period. Twenty-two of them were in NCSE, and only one was treated with thiopental.
Conclusions: Stimulus-induced generalized epileptiform discharges is an EEG pattern occurring in patients with NCSE treated with thiopental. The clinical relevance and pathophysiology of stimulus-induced generalized epileptiform discharges remain to be clarified.