An anoxic brain injury is a life-threatening injury that occurs due to a partial or complete lack of oxygen in the brain, according to BrainandSpinalCord.org. This type of injury can occur when the brain receives an inadequate oxygen supply for longer than five minutes, and it can cause cognitive problems.
Anemic anoxia results when insufficient oxygen is carried through the blood into the brain, and toxic anoxia occurs when toxins such as carbon monoxide enter the body, as stated by BrainandSpinalCord.org. Stagnant anoxia may be caused by an internal condition such as a stroke, while anoxic anoxia occurs when the air does not provide sufficient oxygen. Some causes of anoxia include drowning, suffocation, heart attack, brain tumors and electrical shock.
Loss of consciousness or coma is normally the first symptom of anoxic brain injury, meaning that the sufferer appears to be asleep but does not respond to stimulation, according to BrainandSpinalCord.org. After this, patients may enter a vegetative state in which they appear to be awake but are unresponsive. If patients become conscious, they may experience symptoms typical of brain trauma that vary in severity depending on the extent of the brain damage. These may include short-term memory loss, difficulty using words, headaches, lack of coordination and movement disorders.