Challenge of diagnosing non-convulsive status epilepticus presenting as delirium

Nonconvulsive status epilepticus (NCSE) is relatively common in older people. Although NCSE is a known cause of delirium, diagnosis is often delayed or missed.

We report three cases where NCSE was identified as the cause of delirium in older people that illustrate the challenge of diagnosis.

The cases illustrate that clinical manifestations such as slight twitching of the eyelids or periorally, eye signs, automatisms and disorders of speech and language are often very subtle. Electroencephalography (EEG), and monitoring the clinical and EEG effects of intravenous anticonvulsants, are crucial to diagnosis. Increased availability of portable EEG machines will facilitate early diagnosis. In situations where an EEG is not easily available, a trial of treatment is warranted. Hypoactive delirium is the main variant seen in NCSE but psychosis may also occur.

Clinicians should maintain a high index of suspicion for NCSE in patients with delirium especially when no other obvious cause is identified.