What is an anoxic brain injury? Causes, signs, treatment and outlook

What is an anoxic brain injury?

Anoxic brain injury occurs when the brain does not get enough oxygen, unlike traumatic brain injury, which is caused by direct physical trauma. The most common cause of anoxic brain damage is stroke, although stroke is not the only cause [2].

What causes anoxic brain damage?

Anoxic brain injury occurs when the brain does not receive enough oxygen. The condition is extremely serious and can lead to severe disability, coma or even death. A person can develop an anoxic brain injury for the following reasons [3]:

  • Stroke
  • Low blood pressure
  • close to drowning
  • Severe asthma attack
  • Carbon monoxide poisoning
  • Choking
  • Cardiac or respiratory arrest
  • Irregular heartbeat or poor heart muscle function after a heart attack
  • Suffocation
  • Strangulation
  • A complication of general anesthesia
  • High altitude exposure
  • Smoke inhalation
  • Poisoning
  • Drug overdose
  • Electrical shock

What are the signs and symptoms of an anoxic brain injury?

Anoxic brain injury can cause symptoms ranging from mild short-term problems such as dizziness or trouble concentrating to serious long-term problems such as vision, speech, and memory loss. [4].

Anoxia will cause the body to increase blood flow to the brain in an effort to restore an adequate supply of oxygen. There is, however, only one possibility of increasing cerebral blood flow to about twice its normal level. Anoxia will lead to brain dysfunction if there is not enough brain function to compensate for the loss of oxygen.

Mild anoxic brain injury: A mild form of anoxia can lead to problems with concentration, attention, coordination and short-term memory which can be relatively subtle at first. Headache, dizziness, lightheadedness, increased breathing rate and sweating may occur. In addition to a restriction in the field of vision, numbness or tingling may be felt and feelings of euphoria [5].

Severe anoxic brain injury: Symptoms associated with severe anoxia include confusion, restlessness or drowsiness, as well as cyanosis – a blue discoloration of the skin caused by low levels of oxygen in the blood, commonly seen on the lips, mouth and fingertips.

In addition to brief twitching of the limbs (myoclonus) and seizures, there may also be brain damage caused by a lack of oxygen. Depending on the severity of anoxia, a person may lose consciousness and go into a coma [6].


Types of Anoxic Brain Injury

Anemic anoxia: Anemic anoxia is caused when the blood cannot carry enough oxygen or there is not enough blood in the body to meet the oxygen needs of the brain [7].

Toxic anoxia: Toxic anoxia occurs when chemicals or poisons interfere with the brain’s ability to receive oxygen from the blood.

Anoxic anoxia: This happens when there is not enough oxygen in the air, causing suffocation.

Can anoxic brain damage be treated?

Based on the details of what happened and the condition of the patient at the time of hospitalization, it is usually quite easy to diagnose anoxic brain injury at an early stage. However, anoxia can be caused by a variety of factors, so immediate treatment will depend on the particular circumstances. The goal in all cases is to restore a normal heart rate, blood pressure and adequate oxygenation of the brain.

In some cases, patients may experience medically induced cooling, also known as therapeutic hypothermia. Evidence suggests it may reduce the oxygen and energy needs of brain cells, thereby aiding recovery [8].

What happens when a person suffers an anoxic brain injury?

Predicting the outcome of cerebral anoxia can be aided by several factors, including the following [9][10]:

Age: People over 50 tend to fare worse overall than those under 50 with acquired brain injury, both in terms of the likelihood of survival in the first place and in terms of later recovery. long term.

Duration of the anoxic episode: Depending on the extent of brain damage, the outcome will vary. This will depend on how long the brain was deprived of oxygen, which can often be estimated based on information about what happened.

Coma duration: After an anoxic episode, the duration of unconsciousness reflects the severity of the brain injury and helps predict the outcome.

Student reaction: When bright light is shone into the eyes, the pupils usually constrict. After brain injury, however, this reflex can be lost, resulting in dilated, fixed pupils that don’t respond to light. In the case of an anoxic brain injury, it is not a positive sign that the brainstem is functioning abnormally.


On a final note…

The severity of anoxia and the extent of irreversible brain damage will determine the long-term consequences. In cases of mild or short-lived anoxia, there is a good chance that a normal or nearly normal level of functioning will be restored.

However, if the anoxic injury is more severe, the outcome is less certain and there are likely long-term effects. These problems vary from person to person, depending on the severity of the injury and the areas of the brain affected – in some cases, coma and death can result.

About Antoine L. Cassell

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