title: Evaluation and treatment of altered mental status patients in the emergency department: Life in the fast lane.
abstract: BACKGROUND
  Altered mental status (AMS) is a very common emergency case, but the exact etiology of many AMS patients is unknown. Patients often manifest vague symptoms, thus, AMS diagnosis and treatment are highly challenging for emergency physicians. The aim of this study is to provide a framework for the assessment of AMS patients. This assessment should allow providers to better understand the etiology of mental status changes and therefore improve diagnostic skills and management.
  
  
  METHODS
  This is a prospective cohort observational study. We recruited all adult patients with undifferentiated AMS at a single center tertiary care academic emergency department over 24 months (June 2009 to June 2011). Demographic characteristics, clinical manifestations, assessment approaches, causative factors, emergency treatments and outcomes were collected prospectively.
  
  
  RESULTS
  In 1934 patients with AMS recruited, accounting for 0.93% of all emergency department (ED) patients, 1 026 (53.1%) were male, and 908 (46.9%) female. Their average age was 51.95±15.71 years. Etiologic factors were neurological (n=641; 35.0%), pharmacological and toxicological (n=421; 23.0%), systemic and organic (n=266; 14.5%), infectious (n=167; 9.1%), endocrine/metabolic (n=145; 7.9%), psychiatric (n=71; 3.9%), traumatic (n=38; 2.1%), and gynecologic and obstetric (n=35; 1.9%). Total mortality rate was 8.1% (n=156). The death rate was higher in elderly patients (≥60) than in younger patients (10.8% vs. 6.9%, P=0.003).
  
  
  CONCLUSIONS
  Patients with AMS pose a challenge for ED physicians. The most frequently encountered diagnostic categories causing AMS were primary CNS disorders, intoxication, organ system dysfunction, and endocrine/metabolic diseases. AMS has a high fatality rate in the ED. AMS is an important warning signal for ED patients because of its potentially fatal and reversible effects. Prompt evaluation and treatment are essential to decreasing morbidity and mortality associated with AMS.
authors.affiliation: Department of Medicine, Beijing Puren Hospital, Beijing 100062, China.
authors.forename: Hai-Yu
authors.initials: HY
authors.lastname: Xiao
authors.affiliation: Department of Behavioral Science and Health Education, Emory University Rollins School of Public Health, Atlanta, USA.
authors.forename: Yu-Xuan
authors.initials: YX
authors.lastname: Wang
authors.affiliation: Department of Emergency Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Teng-da
authors.initials: TD
authors.lastname: Xu
authors.affiliation: Department of Emergency Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Hua-Dong
authors.initials: HD
authors.lastname: Zhu
authors.affiliation: Department of Emergency Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Shu-Bin
authors.initials: SB
authors.lastname: Guo
authors.affiliation: Department of Emergency Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Emergency Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing 100730, China.
authors.forename: Xue-Zhong
authors.initials: XZ
authors.lastname: Yu
keywords: Algorithm; Altered mental status; Assessment; Clinical feature; Demographic characteristics; Emergency department; Etiology; Mortality