Abstracts

To evaluate risk and associated factors of NCSE events in the 75-year-old and older population.
Background: Mental status changes are very common in elderly patients. NCSE, a potentially treatable disorder, is one important underdiagnosed etiology usually associated with a history of epilepsy, acute medical disease, and use or withdrawal of different medications. Nevertheless, there are no clinical trials focusing on NCSE and its associated factors in the elderly population. Case-control study
We retrospectively evaluated the clinical manifestations and EEG findings in 19 consecutive elderly patients presenting with 20 NCSE events (group 1, mean age 83.3 years old). NCSE was characterized as at least 30 minutes long mental status changes (confusion or depressed level of consciousness) and continuous EEG epileptiform activity.
We compared patients in group 1 with those of a similar age control group (Group 2, n:28 patients; mean age: 83.3 years) with at least 30 minutes long acute confusion or depressed level of consciousness without obvious cause but without EEG status epilepticus criteria.
The criteria compared included presence of brain lesions on CT or MRI, number of concomitant chronic active diseases, previous neurological disorders, number of medications at the onset of the mental disturbance, frequency of metabolic disorders, withdrawal of medications, and outcome (mental status improvement vs. lack of improvement or death)Statistical analysis was performed using Chi Square and Fisher[apos]s exact two-tailed tests. Of the 20 NCSE events, 8 occurred prior to admission while 12 occurred after admission. Etiology was epilepsy in 2, acute medical problems in 14 (unrelated to surgery in 9, post-surgery in 5) and cryptogenic in 4.
A history of epilepsy was common in patients with NCSE (p=0.017) although it was only present in 30 % of patients in this group. The use of opiates for analgesia (p=0.001) and a worse outcome (p=0.0003) were significantly more common in patients with NCSE. The percentage of patients who developed new onset mental status changes during hospitalization was higher in group 1 (p=0.05).
There were no statistical differences between both groups regarding: frequency of chronic active disease, dementia or cerebrovascular accidents, metabolic disorders, cortical lesions on CT or MRI. The number of patients on antibiotics or anti-depressive drugs, or on withdrawal of psychoactive medications was similar in both groups. NCSE is an important etiology of mental status changes among the elderly population. Most of these patients lack a history of epilepsy, and the use of opiates was associated with the onset of NCSE. Elderly patients with mental status changes with and without NCSE cannot be differentiated clinically, and only the prompt use of EEG can determine the diagnosis.