Non-Convulsive Status Epilepticus in Adults With Altered Mental Status

What was studied

This systematic review with meta-analysis examined how often non-convulsive status epilepticus (NCSE) occurs in patients with altered mental status.

Researchers searched three databases and included 20 studies covering 23,068 patients with altered mental status.

What they found

Across the included studies, the reported prevalence of NCSE ranged widely, from 0.1% to 49.1%. Among patients admitted to neurological intensive care units, it ranged from 10.48% to 27.5%. Among comatose patients, it ranged from 8.1% to 8.8%.

In studies reporting seizure classifications, NCSE represented 0.7% to 1.4% of all seizures and 46.9% of status epilepticus cases. Overall, the review found that NCSE occurred in a substantial proportion of patients with altered mental status.

Limits of the evidence

The estimates varied greatly across studies, and the abstract does not report a single pooled prevalence estimate.

Most available studies were small cohort studies with limited power to determine the prevalence of NCSE. The review therefore calls for caution when interpreting the estimates and recommends larger, well-designed cohort studies.

For families and caregivers

NCSE occurs without prominent motor activity, so it can be subtle and may be underrecognized or underdiagnosed. This review found that it occurred in some patients with altered mental status, including patients in neurological intensive care units and those in a coma. The wide range of estimates means the findings do not show that most people with altered mental status have NCSE.

What to watch next

Larger, well-designed cohort studies are needed to provide more accurate estimates of how often NCSE occurs in patients with altered mental status.

Terms in this summary

Non-convulsive status epilepticus (NCSE)

Status epilepticus that occurs without prominent motor activity.

Altered mental status (AMS)

A change in awareness, thinking, behavior, or level of consciousness.

Status epilepticus (SE)

A seizure lasting more than five minutes, or two or more seizures occurring within five minutes without complete recovery of consciousness between them.

Prevalence

The proportion of a group found to have a condition.

Systematic review

A structured search and assessment of available studies addressing a specific research question.

Meta-analysis

A statistical method used to combine findings from multiple studies, although the abstract does not report a single overall combined prevalence estimate.

Cohort study

A study that examines a defined group of people to measure one or more outcomes.

Neurological intensive care unit

A hospital unit providing intensive care for people with serious conditions affecting the brain or nervous system.