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- Seizures are a relatively common occurrence in the intensive care unit, but may be difficult to recognize.
- Seizures that persist longer than 5 to 7 minutes should be treated to prevent progression to status epilepticus.
- Three major factors determine outcome in status epilepticus: type of seizure, cause, and duration.
- Electroencephalographic (EEG) monitoring to titrate therapy should be implemented in seizing patients who do not awaken promptly after institution of antiepileptics, even if tonic-clonic motor activity resolves.
- Lorazepam is a preferred agent for initial treatment, followed by consideration of additional agents for long-term management or to “break” status epilepticus.
- Patients with refractory status epilepticus require intubation, mechanical ventilation, and aggressive treatment with antiepileptics titrated to the EEG.
- The underlying cause of the seizure disorder must be sought in tandem with treatment of the seizure disorder itself.
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Seizures are a relatively common occurrence in the ICU, complicating the course of about 3% of adult intensive care unit patients admitted for nonneurologic conditions.1 Status epilepticus (SE) may be the primary indication for admission, or it may occur in any ICU patient during a critical illness. A seizure may be the first indication of a central nervous system (CNS) complication or the result of overwhelming systemic disease. Seizures in the setting of critical illness are often difficult to recognize and require a complex diagnostic and management strategy. Delay in recognition and treatment of seizures is associated with increased mortality;2 thus the rapid diagnosis of this disorder is mandatory.
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Status epilepticus refers to a protracted seizure episode or multiple frequent seizures lasting 30 minutes or longer. Although conventional definitions of SE have used this time window, clinicians should recognize that most seizures will terminate spontaneously within a few minutes.3 Recent data suggest that only half of seizure episodes lasting 10 to 29 minutes will stop spontaneously.4 Therefore seizures that persist longer than 5 to 7 minutes should be treated to prevent progression to SE.5
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Limited data are available on the epidemiology of seizures in the ICU. A 10-year retrospective study of all ICU patients with seizures at the Mayo Clinic revealed that 7 patients had seizures per 1000 ICU admissions.5 Our 2-year prospective study of medical ICU patients identified 35 with seizures per 1000 admissions.1 The incidence of generalized convulsive SE (GCSE) in the United States is estimated to be up to 195,000 episodes per year,6 but it is unknown how many of these patients require care in an ICU. The incidence of SE in the elderly is almost twice that of the general population.7 Eight percent of hospitalized comatose patients in a recent series were found to be in electrographic status epilepticus.8 Seizures are probably even more frequent in the pediatric ICU, as children in the first year of life have the highest incidence of SE of any age group studied.5
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Table 64-1 summarizes the most common causes ...