Anoxia occurs when a person’s body or brain stops getting oxygen. The loss of oxygen to the body or brain can be extremely harmful and even life-threatening.

In this article, we look at the most common causes and symptoms of anoxia, as well as how the effects of anoxia are treated.

Person holding model of brain with blood vessels to demonstrate anoxia.Share on Pinterest
Anoxia is when the body or brain does not get enough oxygen.

Anoxia is an extreme form of hypoxia. Hypoxia occurs when one part of a person’s body, such as the brain, can only obtain a reduced amount of oxygen. Anoxia occurs when the body does not get any oxygen. This may result in a hypoxic-anoxic injury.

A lack of oxygen can cause severe damage or even death, so anyone who suspects they may have hypoxia should seek medical attention immediately.

It only takes around 4 minutes without oxygen for the brain to become permanently damaged.

A lack of oxygen in the brain causes brain cells to die and can increase the likelihood of brain damage or death.

Signs and symptoms following mild anoxia include:

  • mood swings or changes in personality or judgment
  • difficulty speaking, slurred speech, or forgetting words
  • weakness
  • feeling dizzy or disorientated
  • an inability to concentrate
  • memory loss
  • a headache
  • difficulty walking
  • problems with coordination

The longer a person is without oxygen, the more apparent the symptoms will become. Experiencing anoxia for several minutes can cause:

  • loss of consciousness
  • collapsing or passing out
  • seizures
  • hallucinations

It is important to note that the symptoms of anoxia may not be immediately apparent because the brain can compensate for diminished oxygen for a few minutes before any symptoms appear.

The initial symptoms may be mild, or a person may ignore them at first. However, immediate medical attention is vital for cases of anoxia.

Some of the different types of anoxia are:

Anemic anoxia

Anemic anoxia takes place where there is not enough hemoglobin in a person’s blood, or the hemoglobin present has become ineffective.

Hemoglobin carries oxygen around the body via the blood. If the hemoglobin is unable to deliver enough oxygen to the organs, they may eventually stop functioning correctly.

Toxic anoxia

Toxic anoxia stops the blood from carrying oxygen around the body effectively. It can occur after a person ingests, absorbs, or inhales certain toxins or other harmful chemicals, such as carbon monoxide.

Stagnant anoxia

Stagnant anoxia happens when a person’s blood does not reach the brain or other parts of the body that require blood to function correctly. This is also known as a hypoxicischemic injury. Cardiovascular problems, such as a stroke or heart failure, are often the cause of stagnant anoxia.

Anoxic anoxia

Anoxic anoxia can happen when there is not enough oxygen available to ensure the body functions properly. This may occur if a person is at a high altitude, where there is limited oxygen in the air.

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Oxygen levels are low at high altitudes, which may cause altitude sickness or anoxia.

There are a variety of situations that could lead to anoxia, including:

  • cardiac or respiratory arrest
  • choking, suffocation, or strangulation
  • a drug overdose
  • carbon monoxide or smoke inhalation
  • blood loss causing the blood pressure to drop
  • irregular heartbeat or damaged heart muscles being unable to pump enough blood and oxygen to the brain
  • other cardiovascular events, including heart attack, stroke, or heart failure
  • an acute asthma attack
  • a severe electric shock
  • exposure to certain toxic chemicals and poisoning
  • high altitudes where oxygen levels are low
  • near drowning
  • a reaction to general anesthesia
  • inadequate oxygen supply or cardiac arrest while under general anesthesia
  • pneumonia
  • low hemoglobin levels in the blood
  • sickle cell anemia or thalassemia

If a person presents with anoxia symptoms, a doctor is likely to perform several tests to try to determine the cause and give an accurate diagnosis.

These tests include:

  • blood tests
  • a magnetic resonance imaging (MRI) scan
  • a functional magnetic resonance imaging (fMRI) scan
  • a computed tomography (CT) scan to produce images of the brain
  • an electroencephalogram (EEG) to test a person’s electrical brain activity
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Physical therapy may be required to rehabilitate someone who has experienced anoxia.

The types of treatment available will depend on the cause of anoxia and how long the person was deprived of oxygen.

The priority for a doctor will be to try and get a person’s oxygen levels back to normal. This could include performing cardiopulmonary resuscitation (CPR) or using a ventilator to help increase a person’s oxygen levels.

The faster a person receives treatment, and the sooner oxygen levels can return to normal, the better a person’s chances are of making a full recovery. Immediate treatment can also reduce the likelihood of further complications.

Treatment for complications of anoxia may include:

  • physical therapy to help a person regain control over their motor functions
  • speech therapy to help a person recover the ability to speak or swallow
  • counseling or psychotherapy to help adjust to any life changes
  • occupational therapy to help a person adapt to new routines
  • recreational therapy can help a person stay involved in the community and continue to learn new things

Treatment may take place at a rehabilitation center that specializes in helping people with brain injuries recover, cope, and adjust to new routines.

The effectiveness of any treatment for anoxia is dependent on a variety of factors, including:

  • age
  • how long the brain was deprived of oxygen
  • the presence and length of a coma

Younger people tend to recover faster than those over the age of 50. Good improvement and progress during the first month of treatment may suggest a more favorable outcome, but it can be over a year before it is possible to determine how a person will recover.

Hypoxic-anoxic brain injuries are very serious and can cause severe and permanent damage.

Being aware of the symptoms of hypoxia and anoxia and seeking immediate medical care is crucial. A quick medical response can help reduce complications and determine the speed and success of recovery.

While some people make a complete recovery, there are many treatment options for those who need support after a brain injury to help them rehabilitate, including physical, mental, and occupational therapy.