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Anoxic brain damage is injury to the brain due to a lack of oxygen. Brain cells without oxygen will begin to die after about four minutes.

Progression of Anoxic Brain Damage

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Oxygen is carried to the brain in the blood. Anoxic brain damage may occur if:

• Blood flow to the brain is blocked or slowed. This can happen with:
  • Blood clot or stroke—blood flow to an area of the brain is blocked
  • Shock and heart problems, like heart attack—blood is not pumped effectively enough to reach the brain
• The blood flow is normal but the blood is not carrying enough oxygen. This may happen because of medical conditions like:
  • Lung disease—oxygen has trouble passing from the lungs to the blood
  • Chronic anemia—a condition that results in low red blood cells, these cells carry the oxygen in blood
• You have exposure to certain poisons or other toxins. For example, carbon monoxide poisoning keeps your blood from picking up oxygen.
• There is a lack of oxygen in the air. This can occur at high altitudes.

The following accidents and health problems increase your risk of anoxic brain damage:

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

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 personality change
• Intermittent loss of consciousness
• Seizures
• Parkinson’s like syndrome
• Abnormal muscle jerks with movements

Rarely there may be a decline in brain function a few days or weeks after the event occurred. This is caused by delayed injury in the brain. Symptoms may then improve gradually over time.

The doctor will ask about your symptoms and medical history. A physical exam will be done. You may need to see a doctor who specializes in brain problems.

These tests may be ordered to learn the extent of the brain damage and the part of the brain that is involved:

• Head CT scan —a type of x-ray that uses a computer to make detailed images of the brain
• MRI scan —a test that uses magnetic waves to make pictures of structures inside the head
• Electroencephalogram (EEG) —a test that measures the electrical activity generated by the brain
• SPECT scans—a type of CT scan that examines areas of the brain for blood flow and metabolism.
• Evoked potential tests—tests used to evaluate the visual , auditory, and sensory pathways

To reduce the risk of anoxic brain damage:

• Chew your food carefully.
• Learn to swim.
• Carefully supervise young children around water.
• Stay clear of high voltage electrical sources (including exposure to lightning).
• Avoid chemical toxins and illicit drugs.
• Check gas burning appliances for carbon monoxide production and install carbon monoxide detectors.