Coma and impaired consciousness in the emergency room: characteristics of poisoning versus other causes.

OBJECTIVES: Unconscious patients represent a diagnostic challenge in the emergency room (ER), but studies on their characteristics are limited. The aim of this study was to investigate the frequency, characteristics and prognosis of different coma aetiologies with special focus on poisoning.
DESIGN: An observational study of consecutive adults admitted to the non-surgical ER, with a Glasgow coma scale (GCS) score of 10 or below. The GCS score on admission was prospectively entered into a study protocol, which was complemented with data from the medical record within one month.
RESULTS: 938 patients were enrolled. Poisoning caused unconsciousness in 352 cases (38%). In the remaining 586 cases (non-poisoning group) the underlying cause was a focal neurological lesion in 24%, a metabolic or diffuse cerebral disturbance in 21%, epileptogenic in 12%, psychogenic in 1% and was still not clarified at hospital discharge in 4%. Among patients below the age of 40 years, the coma was caused by poisoning in 80%, but among those over 60 years, poisoning was the cause in only 11%. The median GCS score on admission was identical in the two study groups. Hospital mortality rates were 2.8% and 39% in the two groups, respectively.
CONCLUSION: Poisoning was the most common cause of coma and young age was a strong predictor of this condition. The prognosis was favourable among poisoned patients but poor in the rest of the study population as a group.