Abstracts

Nonconvulsive status epilepticus (NCSE) is most often defined as an epileptic state, without convulsive motor activity, lasting at least 30 minutes with associated ictal EEG activity. A clinically evident, sustained change from baseline behavior or mental status should also occur unless the patient is comatose or in simple partial NCSE. Diagnostic challenges are most evident in NCSE patients presenting with stupor or coma since no or only little behavioral changes are clearly apparent. Identifying EEG patterns that are most probably ictal representations of NCSE could be most valuable in early diagnosis and treatment of NCSE. Delay to diagnosis of adult NCSE may increase morbidity and mortality. A thorough review of the literature from 1972 to 2004 identified 72 publications involving NCSE in adults. Clinical and EEG presentations of reported cases were analyzed and supplemented with examples from our clinical practice. We devised a classification scheme summarizing clinical presentations and ictal EEG patterns of NCSE. Five clinical categories combined with common ictal EEG signatures were identified and referenced in five charts integrating the type of NCSE, common patient symptomatology, ictal EEG, interictal EEG, and prognostic information. Two flow charts (combining clinical presentation and EEG ) were developed to aid in classification and provide prognostic information for most adult patients in NCSE whose mental state ranges from mild confusion to stupor and for patients who are comatose. The use of benzodiazepines as a diagnostic aide during EEG was scrutinized. Classification of prolonged ictal confusion, stupor and coma utilizing clinical and EEG presentations into a simple logical framework is possible and may contribute to early diagnosis and timely treatment of NCSE. High awareness of NCSE as a clinical entity presenting as change in mental status is critical for early diagnosis and intervention.