Anoxic Brain Damage
all information

Anoxic Brain Damage

(Anoxic Brain Injury; Hypoxic Brain Injury)

Pronounced: An-OKS-ik

En Español (Spanish Version)


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


© 2008 Nucleus Medical Art, Inc.


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)

Risk Factors

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:


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
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 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.


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


American Brain Injury Society

Brain Injury Association of America


Brain Injury Association of Alberta

Ontario Brain Injury Association


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Biagas K. Hypoxic-ischemic brain injury: advancements in the understanding of mechanisms and potential avenues for therapy. Curr Opin Pediatr . 1999;11:223-228.

Hopkins R, Haaland K. Neuropsychological and neuropathological effects of anoxic or ischemic induced brain injury. J Int Neuropsychol Soc . 2004;10:957-961.

Juul S. Erythropoietin in the central nervous system, and its use to prevent hypoxic-ischemic brain damage. Acta Paediatr Suppl . 2002;91:36-42.

Ramani R. Hypothermia for brain protection and resuscitation. Current Opinions in Anesthesiology . 2006;19:487-491.

Last reviewed January 2008 by Rimas Lukas, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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