coma (medicine) - Contrasts to other conditions, Distinctive phases of coma, Outcome, Records

A state of unconsciousness from which individuals cannot be roused. Brain functions are progressively depressed, but the vital activities of respiration and constriction of the heart continue. The causes include trauma to the brain, meningitis, alcohol and drug overdosage, and metabolic disorders such as severe kidney and liver failure and complications of diabetes.

Name of Symptom/Sign:
Coma
Classifications and external resources

ICD-10	R40.2
ICD-9	780.01

In medicine, a coma (from the Greek koma, meaning deep sleep) is a profound state of unconsciousness.

Contrasts to other conditions

Some conditions share characteristics with coma and must be ruled out in a differential diagnosis before coma is conclusively diagnosed.

The difference between coma and stupor is that a patient with coma cannot give a suitable response to either noxious or verbal stimuli, whereas a patient in a stupor can give a crude response, such as screaming, to an unpleasant stimulus.

Some psychiatric diseases appear similar to coma.

Coma is also to be distinguished from the persistent vegetative state which may follow it.

Likewise, coma is not the same as brain death, which is the irreversible cessation of all brain activity.

Coma is different from sleep;

Distinctive phases of coma

Within coma itself, there are several categories that describe the severity of impairment.

Two scales of measurement frequently used in TBI diagnosis to determine the phase of coma are the Glasgow Coma Scale and the Ranchos Los Amigos Scale. The RLAS is a more complex scale that describes up to eight separate levels of coma, and is often used in the first few weeks or months of coma while the patient is under closer observation, and when shifts between levels are more frequent.

Outcome

There are several levels of coma, through which patients may or may not progress. As coma deepens, responsiveness of the brain lessens, normal reflexes are lost, and the patient no longer responds to pain. A deeper coma alone does not necessarily mean a slimmer chance of recovery, because some people in deep coma recover well while others in a so-called milder coma sometimes fail to improve.

The outcome for coma and vegetative state depends on the cause, location, severity and extent of neurological damage: outcomes range from recovery to death.

Comas generally last a few days to a few weeks, and rarely last more than 2 to 4 weeks. After this time, some patients gradually come out of the coma, some progress to a vegetative state, and others die. Time is the best general predictor of a chance for recovery, with the chances for recovery after 3 months of brain damage induced coma being low (less than 10%), and full recovery being very low.

The most common cause of death for a person in a vegetative state is secondary infection such as pneumonia which can occur in patients who lie still for extended periods.

Records

According to the Guinness Book of Records, the longest period of time spent in a coma was by Elaine Esposito. She died on November 25, 1978 at age 43 years 357 days, having been in a coma for 37 years 111 days.

The Glasgow Coma Scale is used to quantify the severity of a coma.

In Germany, music therapy is used to attempt to arouse patients from coma.