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Anoxic Brain Damage

  • Cynthia M. Johnson, MA
Publication Type:


Anoxic Brain Damage

(Anoxic Brain Injury; Hypoxic Brain Injury)


Anoxic brain damage (ABD) is harm to the brain due to a lack of oxygen. Brain cells that do not have enough oxygen will start to die after about 4 minutes.

Progression of Anoxic Brain Damage.

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Oxygen is carried to the brain in the blood. ABD is when:

  • Blood flow is blocked or slowed due to:
  • Blood flow is normal, but the blood does not have enough oxygen due to:
    • Lung disease
    • A lack of oxygen in the air—this may happen at high altitudes
    • Being around certain poisons, such as carbon monoxide
    • An event that is stopping breathing, such as drowning, choking, or suffocation

Risk Factors

Problems that may raise the risk of ABD are:


Problems may be:

  • Headache
  • Problems with thinking and focus
  • Mood swings
  • Loss of consciousness
  • Seizures
  • Clumsiness
  • Coma
  • A decline in brain function days or weeks after the event (this is rare)


The doctor will ask about symptoms and health history. A physical exam will be done. A doctor who treats brain problems may need to be seen.

These tests may be done to find out more about problems with how the brain is working:

  • CT scan
  • MRI scan
  • Electroencephalogram (EEG)—a test that measures the electricity in the brain
  • Single-photon emission computed tomography (SPECT) scans—a type of CT scan that looks at parts of the brain
  • Evoked potential tests—tests used to check the senses



ABD is often caused by accidents. These cannot always be prevented.

Initial Treatment

Treatment will depend on the cause. Choices are:

  • Oxygen to raise the amount of oxygen in the blood
  • Medicine to help get enough blood with oxygen to the brain
  • Cooling the brain to limit problems




  • Cerebral hypoxia. National Institute of Neurological Disorders and Stroke website. Available at: https://www.ninds.nih.gov/health-information/disorders/cerebral-hypoxia.
  • Hypoxic-ischemic brain injury in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/hypoxic-ischemic-brain-injury-in-adults.
  • Rubinos, C. and Ruland, S. Neurologic complications in the intensive care unit. Curr Neurol Neurosci Rep, 2016; 16 (6): 57.


  • Rimas Lukas, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.