Causes of Coma

There are many things that can cause coma or other states of unconsciousness. Some causes are treatable and reversible, and others are not. Some of them are focal processes—localized abnormalities that exist only in one part of the brain—others are diffuse processes that affect large parts of the brain.

Focal Processes and Coma

Focal processes that are localized to a specific spot in the brain and can lead to coma include:

  • Bain hemorrhage, an abnormal flow of blood that occurs in a specific place in the brain
  • Ischemic stroke, a stroke due to the obstruction of a blood vessel in the brain
  • Brain tumor
  • Brain abscesses, infections in the brain

Diffuse Processes and Coma

Diffuse processes that are widespread and affect large parts of the brain include the following:

  • Head trauma associated with an increased intracranial pressure
  • Various toxins, including poisons, alcohol and other drugs (e.g., barbiturates, opiate narcotics, sedatives, amphetamines, cocaine, aspirin)
  • Metabolic abnormalities that lead to either elevated or reduced glucose levels in the blood
  • Liver or kidney failure
  • Hypoxia (poor oxygenation)
  • Imbalance of electrolytes (substances like salts that are found in the blood and tissues and play essential roles in normal body function)
  • Central nervous system infections (e.g., meningitis, encephalitis)
  • Hemorrhage in one of the membranous layers covering the brain
  • Seizure disorders
  • Extreme elevation in blood pressure

Psychiatric Cause for Coma

Sometimes, it is difficult to know if a person's unresponsiveness is due to psychiatric problems rather than a medical illnesses.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 01 Jan 2000

Last Modified: 08 Sep 2015