Investigating the prevalence and clinical symptoms of non-convulsive seizures in emergency department patients with unexplained altered consciousness using real-time portable continuous electroencephalographic monitoring

Kim, Soo Wook; Yang, Won Soek; Kim, Jin Hyouk; Ha, Sang Ook; Park, Young Sun

J Korean Soc Emerg Med > Volume 35(5); 2024 > Article

Original Article

Journal of The Korean Society of Emergency Medicine 2024;35(5): 353-363.

설명되지 않는 의식저하를 주소로 응급실로 방문한 환자들에게 실시간 휴대용 연속 뇌파검사를 시행하여 비경련성발작의 유병율 및 임상증상 조사

김수욱¹

¹한림대학교 성심병원 응급의학과
²한림대학교 성심병원 신경과

Investigating the prevalence and clinical symptoms of non-convulsive seizures in emergency department patients with unexplained altered consciousness using real-time portable continuous electroencephalographic monitoring

¹Department of Emergency Medicine, Hallym University Sacred Heart Hospital, Hallym University Medical Center, Anyang, Korea
²Department of Neurology, Hallym University Sacred Heart Hospital, Hallym University Medical Center, Anyang, Korea

Correspondence

Won Soek Yang ,Tel: 031-380-4134, Fax: 031-380-1573, Email: wsyang@hallym.or.kr,

Received: July 18, 2023; Revised: September 10, 2023 Accepted: October 9, 2023. Published online: October 30, 2024.

ABSTRACT

Objective:
A wireless electroencephalography (EEG) headset was applied to patients with an unclear etiology of an altered mental status suspected of non-convulsive seizures in the emergency department.
Method:
The study included patients who presented to the emergency department with an altered mental status from January 1, 2020, to April 30, 2023. The patients with abnormal findings in brain imaging or those with typical seizure movement were excluded. Real-time portable continuous EEG monitoring was conducted on patients with persistent altered consciousness despite receiving conservative treatments and showing improvement in vital signs and blood tests within 3 hours. The baseline characteristics, degree of consciousness alteration and neurological symptoms, initial clinical diagnosis, EEG findings, and medications used in cases where epileptiform discharges were examined. The clinical outcomes were analyzed retrospectively.
Results:
Among 26 patients, six patients showed epileptiform discharges. The final diagnoses included uremic encephalopathy (n=2), septic encephalopathy due to pneumonia (n=1), urinary tract infection (n=1), diabetic ketoacidosis (n=1), and mental change only (n=1). The associated symptoms were myoclonus in three patients and abnormal eye movements in two patients.
Conclusion:
In cases where the causes of altered mental status remain unexplained despite appropriate evaluations and treatments, particularly when accompanied by myoclonus or abnormal eye movements, it is crucial to consider the possibility of non-convulsive seizures and promptly perform an EEG to differentiate and diagnose the underlying condition, even if initial tests and treatments have been performed.

Key words: Emergency department; Non-convulsive seizure; Wireless electroencephalography