Abstracts

Rationale: Psychotropic medications are often used in various psychiatric and neurological conditions. Potential risks of seizures have been reported with these medications. However, increased doses of these medications were not previously known to predispose to epileptiform encephalopathy. We sought to report denovo epileptiform encephalopathy from increased doses of mirtazapine and donepezil. We illustrate the effect of psychotropic medication changes on the electroencephalogram (EEG) and coorelate this with the effect of withdrawal of the medications both clinically and neurophysiologically. Methods: A 79 year old female with a history of mild dementia, major depressive disorder, anxiety and no previous history of seizures was brought in by her family for a two week history of worsening depression and anxiety, superimposed on acute psychosis after psychotropic medication changes. The patient had been stable on mirtazapine 30 milligrams (mg) per day and donepezil 5 mg for several months. Due to worsening depression and anxiety, mirtazapine was increased to 45 mg per day. Donepezil was increased to 10mg and eszopiclone 2mg was started. After these changes were made, the patient had acute psychosis with increased confusion, delusions and incoherent speech. She was admitted to the psychiatric inpatient unit for treatment and evaluation. On admission, eszopiclone was discontinued but mirtazapine and donepezil were continued. Initial metabolic and infectious work up did not reveal any abnormalities. Subsequently, neurology was consulted for her encephalopathy on hospital day 3. Her neurological exam showed only moderate encephalopathy. Results: A routine electroencephalogram (EEG) was performed with findings of frequent bifrontally predominant spikes and polyspike and slow wave discharges as well as mild to moderate background slowing (Figure 1). Subsequently, inpatient ambulatory EEG was done for 48 hours. Initial findings were similar to the previous routine EEG results (Figure 2-a). Due to the concern of epileptiform encephalopathy from psychotropic medications, mirtazapine and donepezil were discontinued on the second day of ambulatory monitoring. After discontinuation of these medications, the EEG showed significant improvement with resolution of interictal epileptiform discharges and faster background with alpha posterior dominant rhythm (Figure 2-b). During these two days of monitoring, there were multiple patient events with confusion, agitation, and psychosis without clear electrographic seizures. Over the next several days, her mental status gradually improved. Psychosis resolved and the patient was able to return home on hospital day 15. Conclusions: In elderly patients, even minor changes of psychotropic medications may predispose them to potential epileptiform encephalopathy and even seizures. New onset of psychosis and encephalopathy in these patients should prompt evaluation with EEG.