(Anoxic Brain Injury; Hypoxic Brain Injury)
Definition
Definition
Anoxic brain damage is injury to the brain due to a lack of oxygen. Hypoxia is the term to describe low oxygen. Brain cells without enough oxygen will begin to die after about 4 minutes.
Progression of Anoxic Brain DamageCopyright © Nucleus Medical Media, Inc.
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Causes
Causes
Oxygen is carried to the brain in the blood. Anoxic brain damage may occur if:
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Blood flow to the brain is blocked or slowed. This can happen with:
- Blood clot or stroke
- Shock and heart problems, like heart attack
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The blood flow is normal but the blood is not carrying enough oxygen. This may happen if:
- You have lung disease
- There is a lack of oxygen in the air, which may occur at high altitudes
- You have prolonged exposure to certain poisons or other toxins, such as carbon monoxide
- You have an event that is stopping you from breathing normally, such as drowning, choking, or suffocation
Risk Factors
Risk Factors
The following accidents and health problems may increase your chance of anoxic brain damage:
- Sudden cardiac arrest or heart attack
- Choking
- Suffocation
- Drowning
- Electrical shock
- Malfunctioning gas appliances that produce carbon monoxide
- Heart arrhythmia
- Stroke
- Drug use
Symptoms
Symptoms
Severe damage may lead to a coma or a vegetative state. Mild to moderate hypoxic brain damage may cause:
- Headache
- Confusion
- Decreased concentration and attention span
- Mood swings and/or personality change
- Intermittent loss of consciousness
- Seizures
- Poor coordination
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.
Diagnosis
Diagnosis
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
- MRI scan
- 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
Treatment
Treatment
Initial Treatment
Treatment of anoxic brain damage will depend on the cause. Some treatment options include:
- Oxygen therapy to increase the amount of oxygen in the blood
- Medication to help get adequate oxygenated blood to the brain
- Efforts to cool the brain to help limit brain damage
Rehabilitation
Recovery from brain damage can be uncertain. It will also take time. Your chance for recovery depends on how long and how severely you were deprived of oxygen. Many people with mild brain damage can usually recover most of the lost functions.
During rehabilitation, you and your family may work with:
- Physical therapist—to retrain motor skills, such as walking
- Occupational therapist—to improve daily skills, such as dressing and going to the bathroom
- Speech therapist—to work on language problems
- Psychologist—for behavior and emotional issues related to the injury
Recovery can take months, or even years. In many cases, full recovery is never achieved, but some can successfully learn to live with any remaining disabilities. In general, the sooner rehabilitation starts, the better the outcome.
Prevention
Prevention
To help reduce your chance of anoxic brain damage:
- Chew your food carefully to avoid choking
- 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
- Install carbon monoxide detectors
RESOURCES:
National Institute of Neurological Disorders and Stroke http://www.ninds.nih.gov
CANADIAN RESOURCES:
Public Health Agency of Canada http://www.phac-aspc.gc.ca
References:
Biagas K. Hypoxic-ischemic brain injury: Advancements in the understanding of mechanisms and potential avenues for therapy. Curr Opin Pediatr. 1999;11(3):223-228.
Hopkins R, Haaland K. Neuropsychological and neuropathological effects of anoxic or ischemic induced brain injury. J Int Neuropsychol Soc. 2004;10(7):957-961.
Juul S. Erythropoietin in the central nervous system, and its use to prevent hypoxic-ischemic brain damage. Acta Paediatr Suppl. 2002;91(438):36-42.
NINDS cerebral hypoxia information page. National Institute of Neurologic Disorders and Stroke website. Available at:
http://www.ninds.nih.gov/disorders/anoxia/anoxia.htm
Updated February 14, 2014. Accessed May 29, 2014.
Ramani R. Hypothermia for brain protection and resuscitation. Curr Opin Anaesthesiol. 2006;19(5):487-491.
Shprecher D, Mehta L. The syndrome of delayed post-hypoxic leukoencephalopathy. Neuro Rehabilitation. 2010:26(1):65-72.
Last Updated: 5/29/2014