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.

Progression of Anoxic Brain Damage

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Anoxic brain damage may occur when:

  • Oxygenated blood cannot reach the brain (eg, when a clot prevents blood flow to the brain)
  • Blood that reaches the brain does not carry enough oxygen (eg, when lung disease prevents oxygen from crossing from the lungs into the blood for transport)
  • Exposure to poisons or other toxins that keep oxygen in the blood from being used by the cells in the brain (eg, carbon monoxide poisoning )

Risk Factors

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


Recovery from anoxic brain damage can be uncertain and can take a long time. Your chance for recovery depends on how long you were exposed to low oxygen. 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

Many people with mild brain damage can usually recover much of their neurologic function or successfully learn to live with any remaining disabilities.


The doctor will ask about your symptoms and medical history. She will also do a physical exam. 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


Initial Treatment

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 to the brain. The doctor will also increase the amount of oxygen reaching the brain. Efforts to cool the brain may also be used to help limit brain damage. In addition, hyperbaric oxygen treatment may be used in cases of anoxia due to carbon monoxide poising.


During rehabilitation, you and your family will work with:

  • 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—works on language problems
  • Neuropsychologist—counsels on behavior and emotional issues related to the injury

Recovery can take months, or even years. In many cases, full recovery is never achieved. In general, the sooner rehabilitation starts, the better the outcome.


Your doctor may have you take the following medications:

  • Anti-epileptic medications—to treat ongoing seizures
  • Clonazepam (eg, Klonopin)—to treat muscle jerks


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.