J Korean Soc Emerg Med.  2024 Oct;35(5):353-363.

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 SW
• Yang WS
• Kim JH
• Ha SO
• Park YS

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.
Methods
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.

Keyword

Emergency department; Non-convulsive seizure; Wireless electroencephalography