Acute confusion or altered mental state: consider nonconvulsive status epilepticus.

Background: The diagnosis of nonconvulsive status epilepticus (NCSE) is particularly challenging in elderly patients. Confusion, personality change, dysphasia, subtle motor activity and nystagmus may be the only presenting signs.

Objective: To review current knowledge about NCSE with special focus on older people.

Methods: Systematic review of the current literature via Medline search.

Conclusion: Although prospective studies are still lacking, NCSE may be one of the most frequently missed diagnoses in patients presenting with altered mental status. Elderly patients are at particular risk of diagnostic errors because of the broad range of presentations of NCSE, significant comorbidities (especially cerebrovascular disease), limited awareness of this particular seizure emergency or difficulties with access to electroencephalography. Although diagnostic criteria and treatment remain controversial, the diagnosis of NCSE is important because it is potentially reversible.