Background: The approach to unconscious patients in the emergency department (ED) is difficult, often depends on local resources and interests, and workup strategies often lack standardization. One reason for this is that data on causes, management, and outcome of patients who present to the ED with sudden onset unconsciousness of unknown cause is limited. Objectives: This study was performed to analyze the causes of acute impaired consciousness in patients in an interdisciplinary ED. Methods: Here, we analyzed all patients who were admitted to the ED of a tertiary care hospital with the dominating symptom of “sudden onset unconsciousness” within 1 year (September 2014 until August 2015). Patients with a clear diagnosis at arrival that explained the altered state of consciousness or other dominating symptoms at the time of arrival were not included. Results: A total of 212 patients were analyzed. In 88% of the patients, a final diagnosis could be established in the ED. Most common causes for unconsciousness were cerebrovascular diseases (24%), infections (14%), epileptic seizures (12%), psychiatric diseases (8%), metabolic causes (7%), intoxications (7%), transient global amnesia (5%), and cardiovascular causes (4%). The diagnoses were predominantly established by physical examination in combination with computed tomography (23%) and by the results of laboratory testing (25%). In-hospital mortality was 11%, and 59% of all patients were discharged with a Glasgow Outcome Score of 2–4. Conclusions: This analysis demonstrates a large variety of etiologies in patients with unknown unconsciousness of acute onset who are admitted to an ED. As neurological diagnoses are among the most common etiologies, neurological qualification is required in the ED, and availability of diagnostics such as cerebral imaging is indispensable and recommended as an early step in a standardized clinical approach.

Kanich W, Brady WJ, Huff JS, et al: Altered mental status: evaluation and etiology in the ED. Am J Emerg Med 2002; 20: 613–617.
Martikainen K, Seppa K, Viita P, et al: Transient loss of consciousness as reason for admission to primary health care emergency room. Scand J Prim Health Care 2003; 21: 61–64.
Horsting MW, Franken MD, Meulenbelt J, et al: The etiology and outcome of non-traumatic coma in critical care: a systematic review. BMC Anesthesiol 2015; 15: 65.
Bjorkman J, Hallikainen J, Olkkola KT, et al: Epidemiology and aetiology of impaired level of consciousness in prehospital nontrauma patients in an urban setting. Eur J Emerg Med 2016; 23: 375–380.
Braun M, Schmidt WU, Mockel M, et al: Coma of unknown origin in the emergency department: implementation of an in-house management routine. Scand J Trauma Resusc Emerg Med 2016; 24: 61.
Howard BM, Kornblith LZ, Conroy AS, et al: The found down patient: a western trauma association multicenter study. J Trauma Acute Care Surg 2015; 79(6): 976–82; discussion 82.
Mistry B, Stewart De Ramirez S, Kelen G, et al: Accuracy and reliability of emergency department triage using the emergency severity index: an international multicenter assessment. Ann Emerg Med 2018; 71: 581–587.
Wuerz RC, Travers D, Gilboy N, et al: Implementation and refinement of the emergency severity index. Acad Emerg Med 2001; 8: 170–176.
Tanabe P, Gilboy N, Travers DA: Emergency severity index version 4: clarifying common questions. J Emerg Nurs 2007; 33: 182–185.
Edlow JA, Rabinstein A, Traub SJ, et al: Diagnosis of reversible causes of coma. Lancet 2014; 384: 2064–2076.
Forsberg S, Hojer J, Enander C, et al: Coma and impaired consciousness in the emergency room: characteristics of poisoning versus other causes. Emerg Med J 2009; 26: 100–102.
Weiss N, Regard L, Vidal C, et al: Causes of coma and their evolution in the medical intensive care unit. J Neurol 2012; 259: 1474–1477.
Forsberg S, Hojer J, Ludwigs U, et al: Metabolic vs structural coma in the ED – an observational study. Am J Emerg Med 2012; 30: 1986–1990.
Lown DJ, Knott J, Rechnitzer T, et al: Predicting short-term and long-term mortality in elderly emergency patients admitted for intensive care. Crit Care Resusc 2013; 15: 49–55.
Forsberg S, Hojer J, Ludwigs U: Prognosis in patients presenting with non-traumatic coma. J Emerg Med 2012; 42: 249–253.
Mirhaghi A, Heydari A, Mazlom R, et al: Reliability of the emergency severity index: meta-analysis. Sultan Qaboos Univ Med J 2015; 15:e71–e77.
van de Beek D, Cabellos C, Dzupova O, et al: ESCMID guideline: diagnosis and treatment of acute bacterial meningitis. Clin Microbiol Infect 2016; 22(suppl 3):S37–S62.
Soar J, Nolan JP, Bottiger BW, et al: European resuscitation council guidelines for -resuscitation 2015: section 3. Adult advanced life support. Resuscitation 2015; 95: 100–147.
Subcommittee A; American College of Surgeons’ Committee on Trauma; International ATLS working group: Advanced trauma life support (ATLS®): the ninth edition. J Trauma Acute Care Surg 2013; 74: 1363–1366.
Ntaios G, Bornstein NM, Caso V, et al: The European stroke organisation guidelines: a standard operating procedure. Int J Stroke 2015; 10(suppl A100): 128–135.
Bernhard M, Becker TK, Nowe T, et al: Introduction of a treatment algorithm can improve the early management of emergency patients in the resuscitation room. Resuscitation 2007; 73: 362–373.
Bekelis K, Marth NJ, Wong K, et al: Primary stroke center hospitalization for elderly patients with stroke: implications for case fatality and travel times. JAMA Intern Med 2016; 176: 1361–1368.
Lichtman JH, Jones SB, Leifheit-Limson EC, et al: 30-day mortality and readmission after hemorrhagic stroke among Medicare beneficiaries in joint commission primary stroke center-certified and noncertified hospitals. Stroke 2011; 42: 3387–3391.
Goodacre S, Nicholl J, Dixon S, et al: Randomised controlled trial and economic evaluation of a chest pain observation unit compared with routine care. BMJ 2004; 328: 254.
Hoang V, Nuwer MR: Changes in emergency department coverage for the neurologist. Neurol Clin Pract 2013; 3: 334–340.
Moore SA, Wijdicks EF: The acutely comatose patient: clinical approach and diagnosis. Semin Neurol 2013; 33: 110–20.
Hansen CK, Fisher J, Joyce NR, et al: A prospective evaluation of indications for neurological consultation in the emergency department. Int J Emerg Med 2015; 8: 74.
Huff JS, Stevens RD, Weingart SD, et al: Emergency neurological life support: approach to the patient with coma. Neurocrit Care 2012; 17(suppl 1):S54–S59.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.