A case of post-cardiac arrest syndrome presenting with lateralized periodic discharges evolving to a cyclic seizure pattern on electroencephalogram

Abstract

A 53-year-old man with hypertension experienced sudden cardiopulmonary arrest. Ambulance crews detected ventricular fibrillation that responded to defibrillation. Cardiopulmonary resuscitation resulted in return of spontaneous circulation (ROSC) after 30 minutes. At admission to our hospital, he was in a comatose state. Therapeutic hypothermia was performed for two days with other supportive care. However, despite these therapies, he remained comatose, and a diagnosis of post-cardiac arrest syndrome (PCAS) was made. On the sixth hospital day, an electroencephalogram (EEG) showed lateralized periodic discharges (LPDs) in the right occipital area evolving to electrographic seizures. Over roughly 15 minutes, this evolution process repeated 10 times, demonstrating a cyclic seizure pattern. Intravenous administration of 10 mg diazepam resulted in temporal attenuation of the high-amplitude discharges followed by LPDs re-emergence accompanying a low-amplitude fast rhythm on the background activity (LPDs+). Antiepileptic drugs administration was continued, along with supportive care. He opened his eyes on the 11th hospital day, after which his general conditions showed a good recovery. He was discharged on the 30th day without any sequelae.