ABSTRACT
The brain has a limited repertoire of responses to injury. Most of these responses are charac-
terized by inhibition; for example, depressed level of consciousness, cognitive impairment, or
focal deficits, such as hemiparesis. In contrast, seizures represent an excitatory response to
brain insult or injury. Seizures may complicate trauma, medical illness, or almost any brain
disorder. They may also occur in the absence of any discernable brain insult or abnormality
(aside from the presence of the seizures themselves). Seizures range from violent convulsions
to clinically enigmatic behavioral changes, diagnosed as seizures only by electroencephalo-
graphy. The life-time probability of having a seizure is 5-10%. The prevalence of epilepsy is
0.5-1% (1). Seizures are relatively common occurrences in acutely ill patients and occur in
3.4% of patients admitted to a medical ICU for nonneurologic reasons (2).
