coma, in medicine

coma, in medicine, deep state of unconsciousness from which a person cannot be aroused even by painful stimuli. The patient cannot speak and does not respond to command. Coma is the result of damage to the brain stem brain stem, lower part of the brain , adjoining and structurally continuous with the spinal cord. The upper segment of the human brain stem, the pons, contains nerve fibers that connect the two halves of the cerebellum .
..... Click the link for more information. and cerebrum that may be caused by severe head or brain injury, cardiac arrest, stroke stroke, destruction of brain tissue as a result of intracerebral hemorrhage or infarction caused by thrombosis (clotting) or embolus (obstruction in a blood vessel caused by clotted blood or other foreign matter circulating in the bloodstream); formerly called
..... Click the link for more information. , diabetes diabetes or diabetes mellitus (məlī`təs)
..... Click the link for more information. , drug overdose, shock shock, any condition in which the circulatory system is unable to provide adequate circulation to the body tissues, also called circulatory failure or circulatory collapse. Shock results in the slowing of vital functions and in severe cases, if untreated, in death.
..... Click the link for more information. , or hemorrhage hemorrhage (hĕm`ərĭj), escape of blood from the circulation (arteries, veins, capillaries) to the internal or external tissues.
..... Click the link for more information. . It occurs just before death in many diseases. There are various depths of coma; the nature of the injury determines the level of supportive treatment necessary (see artificial life support artificial life support, systems that use medical technology to aid, support, or replace a vital function of the body that has been seriously damaged. Such techniques include artificial pacemakers , internal defibrillators , dialysis machines (see kidney, artificial
..... Click the link for more information. ). Survival and prognosis depend upon the cause, extent of damage, and duration of the coma.

The term

persistent vegetative state was coined in 1972 to describe an unconscious state in which sleep and wake cycles remain and eyes may open, but there is no thinking, feeling, or awareness of one's surroundings (although one may react reflexive to certain stimulations). The brain stem is usually relatively intact but the cerebral cortex is severely impaired. It is this state that sometimes results from resuscitation and life support of people who otherwise would have died; partial emergence from such a state sometimes occurs with a year or two, but not after that.

coma, in astronomy

coma, in astronomy: see comet comet [Gr.,=longhaired], a small celestial body consisting mostly of dust and gases that moves in an elongated elliptical or nearly parabolic orbit around the sun. Comets visible from the earth can be seen for periods ranging from a few days to several months.
..... Click the link for more information. .

coma

Complete lack of consciousness, with loss of reaction to stimulus and of spontaneous nervous activity. It is usually associated with cerebral injury of metabolic or physical origin. Simple concussions cause short losses of consciousness. Coma from lack of oxygen may last several weeks and is often fatal. Coma caused by stroke can be sudden, while that caused by metabolic abnormalities (as in diabetes mellitus) or cerebral tumours comes on gradually. Treatment depends on the cause.

coma¹

a state of unconsciousness from which a person cannot be aroused, caused by injury to the head, rupture of cerebral blood vessels, narcotics, poisons, etc.

coma²

1. Astronomy the luminous cloud surrounding the frozen solid nucleus in the head of a comet, formed by vaporization of part of the nucleus when the comet is close to the sun

2. Botany

a. a tuft of hairs attached to the seed coat of some seeds

b. the terminal crown of leaves of palms and moss stems

3. Optics a type of lens defect characterized by the formation of a diffuse pear-shaped image from a point object

coma (redirected from Coma (medicine))

coma, in medicine

coma, in astronomy

coma

coma
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