Seizures and Status Epilepticus in the Intensive Care Unit Wendy C. Ziai, M.D., M.P.H., 1,2,3 and Peter W. Kaplan, M.B., F.R.C.P. 1 ABSTRACT Persistent seizures and failure to regain consciousness following witnessed seizure activity require emergency neurological consultation. Although outcome is largely depend- ent on underlying cause, early maximal anticonvulsant therapy is critical to reducing morbidity. This review covers important concepts in the clinical and EEG diagnosis of status epilepticus, and discusses treatment algorithms for single and recurrent seizures, emphasizing the need to rationalize therapy depending on the presumed duration of seizure activity. The review takes the perspective of the neurological consultant in the intensive care unit, and considers all pharmacological approaches available to the intensivist as described in the current literature and from clinical experience. KEYWORDS: Neurological emergencies, status epilepticus, nonconvulsive status epilepticus, refractory status epilepticus, intensive care The neurologist or neurointensivist may be called on for consultation on an intensive care unit (ICU) patient with overt clinical convulsions, more subtle manifestations of subclinical or of nonconvulsive status, or occasionally on a patient misdiagnosed as being in status epilepticus. This article addresses the diagnosis and management of such patients. EPIDEMIOLOGY In the ICU, the reported risk of seizures as a complication or as the principal reason for ICU admission is 3.3%, although the actual incidence is likely to be significantly higher. 1 In a prospective clinical evaluation of all medical ICU admissions for over 2 years, seizures were second only to metabolic encephalopathy as the cause of neuro- logical complications, occurring in 61 of 217 patients (28.1%). 1 Status epilepticus (the state of ongoing seizure activity typically > 30 minutes, or of multiple seizures without return to baseline) is the diagnosis most often associated with seizures in the ICU, but is rare as an admission diagnosis (0.2%). 2 In a nonneurological ICU, the reported incidence of status epilepticus is 3% with a mortality of 30%. The primary cause of seizures in the ICU is antiepileptic drug (AED) withdrawal or non- compliance, followed by alcohol withdrawal. 3,4 Other common causes are stroke, anoxic brain injury, central nervous system infection, head trauma, sepsis, metabolic disorders, and other acute drug toxicity states or with- drawal (Table 1). Status epilepticus in the critically ill patient is most often caused by the acute illness in patients who did not previously have seizures. 5–7 Nonconvulsive status epilepticus has been described in 8 to 34% of neurological ICU patients in comatose states. 8,9 The most common etiologies in one study were hypoxia in 42%, followed by stroke in 22%. 8 In elderly populations, the mortality from nonconvulsive status epilepticus is as high as 57%. The diagnosis and management of a single seizure, convulsive, and nonconvulsive status epilepticus are reviewed as they pertain to patients in the ICU. Departments of 1 Neurology, 2 Neurosurgery and 3 Anesthesia and Critical Care Medicine, Johns Hopkins University School of Med- icine, Baltimore, Maryland. Address for correspondence and reprint requests: Wendy C. Ziai, M.D., M.P.H., Departments of Neurology, Neurosurgery, and Anesthesia and Critical Care Medicine, The Johns Hopkins Hospi- tal, 600 North Wolfe Street, Meyer 8-140, Baltimore, MD 21287 (e-mail: weziai@jhmi.edu). Neurological Consultation in the ICU; Guest Editors, Romergryko G. Geocadin, M.D., and Matthew A. Koenig, M.D. Semin Neurol 2008;28:668–681. Copyright # 2008 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662. DOI 10.1055/s-0028-1105978. ISSN 0271-8235. 668 Downloaded by: University of Alberta. Copyrighted material.