Nonconvulsive status epilepticus and continuous spike and slow wave of sleep in children

Nonconvulsive status epilepticus (NCSE) is a special epileptic state that can be more common than previously thought in children and adult patients. Currently, there is no universally accepted definition for NCSE. Early and accurate diagnosis depends on a high index of suspicion and rapid availability of electroencephalographic recording. The clinical presentation of NCSE can vary from a mild confusional state to a coma. The underlying etiology is also quite diverse. In critically ill patients, NCSE has been reported with convulsive status epilepticus (CSE), hypoxemia, acute ischemic or hemorrhagic stroke, encephalitis, or trauma. The estimated incidence of NCSE is 15% to 40% in post-CSE, 8% in subarachnoid hemorrhage, and 8% to 10% in coma. As seen in CSE, there is a bimodal distribution with NCSE in critically ill patients; children (age <1 year) and elderly appear to be at great risk. NCSE has also been reported in a number of epilepsy syndromes, such as childhood absence epilepsy, Panayiotopoulos syndrome, Lennox-Gastaut syndrome, and Dravet syndrome. However, it is difficult to determine the incidence of NCSE in an ambulatory setting because of the great variation in clinical presentation and underlying etiology. This review examines the clinical features, outcome, and treatment approach for NCSE in 2 different clinical settings, in ambulatory and critically ill patients. NCSE is reviewed in children and adults to distinguish similarities and differences in their clinical presentation.