The etiology and outcome of non-traumatic coma in critical care: a systematic review.
BACKGROUND
Non-traumatic coma (NTC) is a serious condition requiring swift medical or surgical decision making upon arrival at the emergency department. Knowledge of the most frequent etiologies of NTC and associated mortality might improve the management of these patients. Here, we present the results of a systematic literature search on the etiologies and prognosis of NTC.


METHODS
Two reviewers independently performed a systematic literature search in the Pubmed, Embase and Cochrane databases with subsequent reference and citation checking. Inclusion criteria were retrospective or prospective observational studies on NTC, which reported on etiologies and prognostic information of patients admitted to the emergency department or intensive care unit.


RESULTS
Eventually, 14 studies with enough data on NTC, were selected for this systematic literature review. The most common causes of NTC were stroke (6-54%), post-anoxic coma (3-42%), poisoning (<1-39%) and metabolic causes (1-29%). NTC was also often caused by infections, especially in African studies affecting 10-51% of patients. The NTC mortality rate ranged from 25 to 87% and the mortality rate continued to increase long after the event had occurred. Also, 5-25% of patients remained moderately-severely disabled or in permanent vegetative state. The mortality was highest for stroke (60-95%) and post-anoxic coma (54-89%) and lowest for poisoning (0-39%) and epilepsy (0-10%).


CONCLUSIONS
NTC represents a challenge to the emergency and the critical care physicians with an important mortality and moderate-severe disability rate. Even though, included studies were very heterogeneous, the most common causes of NTC are stroke, post anoxic, poisoning and various metabolic etiologies. The best outcome is achieved for patients with poisoning and epilepsy, while the worst outcome was seen in patients with stroke and post-anoxic coma. Adequate knowledge of the most common causes of NTC and prioritizing the causes by mortality ensures a swift and adequate work-up in diagnosis of NTC and may improve outcome.
Division of Anaesthesiology, Intensive Care and Emergency Medicine, University Medical Centre Utrecht, mailstop Q04.2.313, PO Box 85500, 3508 GA, Utrecht, Netherlands. m.w.b.horsting@umcutrecht.nl.
Marlene Wb B
MW
Horsting
Division of Anaesthesiology, Intensive Care and Emergency Medicine, University Medical Centre Utrecht, mailstop Q04.2.313, PO Box 85500, 3508 GA, Utrecht, Netherlands. m.d.franken@umcutrecht.nl.
Mira D
MD
Franken
Division of Anaesthesiology, Intensive Care and Emergency Medicine, University Medical Centre Utrecht, mailstop Q04.2.313, PO Box 85500, 3508 GA, Utrecht, Netherlands. JanMeulenbelt@umcutrecht.nl.|Department of Intensive Care Medicine and National Poison Information Center, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, Netherlands. JanMeulenbelt@umcutrecht.nl.
Jan
J
Meulenbelt
Division of Anaesthesiology, Intensive Care and Emergency Medicine, University Medical Centre Utrecht, mailstop Q04.2.313, PO Box 85500, 3508 GA, Utrecht, Netherlands. w.a.vanklei@umcutrecht.nl.
Wilton A
WA
van Klei
Division of Anaesthesiology, Intensive Care and Emergency Medicine, University Medical Centre Utrecht, mailstop Q04.2.313, PO Box 85500, 3508 GA, Utrecht, Netherlands. d.w.delange@umcutrecht.nl.|Department of Intensive Care Medicine and National Poison Information Center, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, Netherlands. d.w.delange@umcutrecht.nl.
Dylan W
DW
de Lange
D003128:Coma / Q000209:etiology* / Q000401:mortality; D003422:Critical Care; D004812:Epidemiologic Methods; D004827:Epilepsy / Q000401:mortality; D006801:Humans; D000860:Hypoxia / Q000401:mortality; D018458:Persistent Vegetative State / Q000401:mortality; D011041:Poisoning / Q000401:mortality; D015995:Prevalence; D011379:Prognosis; D020521:Stroke / Q000401:mortality