Non-neurologic Causes of Nonconvulsive Status Epilepticus/Nonconvulsive Seizures

Abstract

Nonconvulsive status epilepticus (NCSE) is an underdiagnosed condition due to its minimal or inconspicuous clinical presentation. With increasing use of continuous electroencephalogram (EEG), NCSE has been diagnosed more frequently in critically ill patients. In 2012, the Neurocritical Care Society defined NCSE as seizure activity on EEG that is continuous or recurrent without return to baseline between seizures for 5 or more minutes that is not associated with convulsive activity. In acutely ill patients, NCSE often follows convulsive status epilepticus and presents with severely impaired mental status with or without subtle motor movements as well as other positive or negative signs [1]. (See Chap. 5 for further NCSE classification). Nonconvulsive seizures (NCS)/NCSE have been reported in 8–21 % of critically ill patient populations [2–4]. Delayed diagnosis and treatment of NCSE may lead to increased mortality which has been reported to be as high as 52 % in critically ill patients [2, 5].