Anoxic Brain Damage
(Anoxic Brain Injury; Hypoxic Brain Injury)
Definition
Anoxic brain damage (ABD) is harm to the brain due to a lack of oxygen. Brain cells without enough oxygen will start to die after about 4 minutes.
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Causes
Oxygen is carried to the brain in the blood. ABD is when:
-
Blood flow is blocked or slowed due to:
- A clot or stroke
- Shock and heart problems, like a heart attack
-
Blood flow is normal, but the blood doesn’t have enough oxygen due to:
- Lung disease
- A lack of oxygen in the air, which 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:
- Sudden cardiac arrest or heart attack
- Choking
- Suffocation
- Drowning
- Electrical shock
- Broken gas appliances that discharge carbon monoxide
- Heart arrhythmia
- Stroke
- Drug use
Symptoms
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 (rare)
Diagnosis
You will be asked about your symptoms and health history. A physical exam will be done. You may need to see a doctor who treats brain problems.
These tests may be done to find out more about problems with brain function:
- 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
Treatment
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
Rehabilitation
Recovery can take months or years. It depends on how long a person went without oxygen. Many people can get back most of the abilities they lost.
These therapies may be needed:
- Physical therapy to retrain motor skills, such as walking
- Occupational therapy to relearn daily skills, such as dressing and going to the bathroom
- Speech therapy to work on language problems
- Counseling for behavior and emotional issues
Prevention
ABD is often caused by accidents. These cannot always be prevented.
RESOURCES:
Brain Injury Association of America
http://www.biausa.org
National Institute of Neurological Disorders and Stroke
http://www.ninds.nih.gov
CANADIAN RESOURCES:
Ontario Brain Injury Association
http://obia.ca
Public Health Agency of Canada
http://www.phac-aspc.gc.ca
REFERENCES:
Cerebral hypoxia information page. National Institute of Neurologic Disorders and Stroke website. Available at: https://www.ninds.nih.gov/Disorders/All-Disorders/Cerebral-Hypoxia-Information-Page. Accessed June 18, 2018.
Rubinos C, Ruland S. Neurologic complications in the intensive care unit. Curr Neurol Neurosci Rep. 2016;16(6):57.
Last reviewed September 2020 by EBSCO Medical Review Board Rimas Lukas, MD Last Updated: 5/21/2021