coma (Greek: a deep, sound sleep, lethargy, trance without sleep).
1. A state of deep, often prolonged unconsciousness, usually the result of injury, disease, or poison, in which an individual is incapable of sensing or responding to external stimuli and internal needs.
2. An abnormal deep stupor occurring as a result of illness or injury in which the patient cannot be aroused by external stimuli. More than 50% of cases are caused by trauma to the head or circulatory accidents in the brain due to hypertension, arteriosclerosis, thrombosis, tumor, abscess formation, or insufficient blood flow to the brain.
Other frequent causes of coma are acute systemic infection of the brain or meninges; acute infection and bacterial intoxication as in fevers, botulism, and other infectious diseases; effects of drugs (alcohol, atropine, barbiturates, chloral, hyoscine, paraldehyde, and phenols); trauma as in accidents, hemorrhage, or electrocution; gases or fumes such as carbon dioxide or carbon monoxide; extreme temperature; and neurosis as in malingering.
Of the nature of, or pertaining to, a coma
In a coma.