Original Contributions
Altered mental status: Evaluation and etiology in the ED*,**

Presented in part at the Society for Academic Emergency Medicine Mid-Atlantic Regional Meeting, Charlotte, NC, March 2001, and at the American College of Emergency Physicians Scientific Assembly and Research Forum, Chicago, IL, October 2001.
https://doi.org/10.1053/ajem.2002.35464Get rights and content

Abstract

The purpose of this study was to determine the etiologies responsible for altered mental status (AMS) in an emergency department (ED) population, to gauge the diagnostic (DX) value of the various features of the clinical evaluation, and to examine patient outcomes. Prospective identification of patients with AMS followed by a retrospective review of the medical record was performed in a university hospital E among ED patients with AMS. Three hundred seventeen patients (5% of the ED patient volume) were identified with a mean age of 49 years (57% men). Descriptions of the AMS included 24% unresponsive, 46% lethargic/difficult to arouse, 12% agitated, and 18% unusual behavior. The most common discharge diagnoses accounting for AMS were neurologic (28%) and toxicologic (21%) followed by trauma (14%), psychiatric (14%), infectious (10%), endocrine/metabolic (5%), pulmonary (3%), oncologic (3%), cardiovascular (1%), gastrointestinal (1%), and renal (1%). The specific features of the clinical evaluation of greatest DX value followed by rates of positive DX finding included history of present event (51%), past medical history (43%), and physical examination (41%); features of little DX value included radiographs (16%), 12-lead electrocardiogram (7%), and various laboratory studies (chemistry panel [5%], complete blood count [1%], coagulation panel [0], urinalysis [11%]). Sixty-four percent of the patients were admitted with a mean hospital stay of 7.6 days and 9% deaths. Common causes of AMS included neurologic, toxicologic, traumatic, and psychiatric syndromes. The patient history and physical examination were most useful in DX terms; ancillary investigations were less often DX. This group represented a minority of the ED population yet rates of ED resource use, hospital admission, and death were high. (Am J Emerg Med 2002;20:613-617. Copyright 2002, Elsevier Science (USA). All rights reserved.)

Section snippets

Methods

This study used a convenience sample design with a prospective identification of patients with AMS followed by a retrospective review of the medical records and retrospective determination of the diagnostic strength of the various aspects of the ED evaluation. Participants were patients with AMS prospectively identified by the attending EP in a university hospital ED with an annual census of 60,000 persons. The study was conducted over a period of 4 months. Three ED attending physicians

Results

Three hundred seventeen patients were entered in the study and represent the sample used for data analysis. This number of study patients represented 5% of the total ED census for these clinical shifts. The mean age of the study patients was 49 years with 57% male gender; refer to Figure 1 for a graphical depiction of the frequency of age occurrence in the study population.

. Frequency of specific age occurrence in the study population.

Of note, 10% of these patients had unknown identity on

Discussion

In the ED, the emergency physician encounters patients with AMS resulting from a range of etiologies involving both primary CNS events as well as secondary processes with an effect on the CNS. Examples of the 2 situations include acute ischemic stroke (the primary CNS event) and urosepsis with significant hypoperfusion (secondary [non-CNS] event with a depressive effect on the CNS). As noted previously, the medical literature provides little information regarding the possible etiologies

Conclusion

Patients presenting to the ED with AMS represent a small but significant percentage of the total patients evaluated; these patients require significant resource utilization by the ED. The combined knowledge of the most frequent causes of AMS and the most useful diagnostic tools in the evaluation of AMS can assist the EP in the management of these demanding and potentially ill patients.

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