Altered Mental Status in the Emergency Department

Austin T. Smith, MD; Jin H. Han, MD, MSc


Semin Neurol. 2019;39(1):5-19. 

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Electroencephalography (EEG) should be performed on all patients with AMS having seizures or if suspicion for NCSE exists. NCSE should be considered in patients with a seizure history, those who seized prior to arrival, and in those in which no etiology of AMS has been discovered, as the incidence of NCSE in patients with AMS is as high as 8 to 30%.[47,142]


An electrocardiogram (ECG) should be considered in patients with AMS, especially if their pulse rate is bradycardic or tachycardic; it may reveal ECG changes secondary to toxic or metabolic causes. An ECG can also be considered in patients who are highly vulnerable to developing AMS or delirium. The ECG should be evaluated for rate, rhythm, intervals, and presence of ischemia. Patients with any concerning findings should be monitored on telemetry in the ED.