Anoxic brain damage happens when the brain receives inadequate oxygen for several minutes or longer. Brain cells begin to die after approximately four minutes without oxygen.

Anoxic brain damage may occur when:

• Oxygenated blood cannot reach the brain (for example, when a clot prevents blood flow to the brain)
• Blood that reaches the brain does not carry enough oxygen (for example, when lung disease prevents oxygen from crossing from the lungs into the blood for transport)
• People are exposed to poisons or other toxins that keep oxygen in the blood from being used by the cells in the brain (for example, carbon monoxide, which binds the oxygen carrying molecules in the blood and prevents transport of oxygen)

A risk factor is something that increases one’s chance of getting a disease or condition. The following accidents and health problems increase your risk of anoxic brain damage:

• Choking
• Suffocation
• Near-drowning
• Electrical shock
• Malfunctioning gas appliances that produce carbon monoxide
• Heart attack
• Heart arrhythmia (abnormal heart beats)
• Stroke
• Brain tumors
• Illegal drug use

Recovery from anoxic brain damage can be uncertain and can take a long time. A person’s chance for recovery depends on the extent of the brain damage and the part of the brain involved. Severe damage may lead to a coma or a vegetative state . Mild to moderate anoxic brain damage may cause:

• Headache
• Confusion
• Decreased concentration and attention span
• Mood swings and/or change is personality
• Intermittent loss of consciousness

The doctor will ask you about your symptoms and medical history (if you are conscious), and perform a physical exam. Patients may be referred to other doctors (a neurologist or neurosurgeon) who specialize in brain problems. Doctors may use the following tests to learn the extent of the brain damage and the part of the brain that is involved:

• Head CT scan—an x-ray test that uses a computer to make detailed images of the brain
• MRI (magnetic resonance imaging)—a test that uses powerful magnets, radio waves, and a computer to make detailed images of the brain
• Electroencephalogram (EEG)—a test that measures the electrical activity generated by the brain
• Evoked potentials (SSEP, BAER, VEP)—tests which electrically evaluate the visual, auditory, and sensory pathways

Treatment of anoxic brain damage depends on the cause. Initially, barbiturates may be used to slow down brain activity; steroids and other medications may be used to reduce the swelling that accompanies injured brain tissue. This may help limit the amount of damage done to the brain. Efforts are also made to increase the amount of oxygen reaching the brain. Efforts to cool the brain may also be used to help limit brain damage.

Recovery can take months, or even years; in many cases, full recovery is never achieved. In general, the sooner rehabilitation starts, the better the patient will fair.

During rehabilitation, the patient and his or her family will likely work with a team of medical professionals, including:

• Physical therapist—helps retrain motor skills such as walking.
• Occupational therapist—works on improving daily skills such as dressing and going to the bathroom.
• Speech therapist—helps works on language problems.
• Neuropsychologist—counsels on behavior and emotional issues related to the injury.