Hypoxia & anoxia

Hypoxia is when the body or brain is partially deprived of oxygen, leading to permanent damage. Anoxia is often a result of hypoxia where the brain or body completely loses its oxygen supply. Total loss of oxygen to the brain can result in severe permanent damage.

Hypoxia and anoxia can affect all major organs, including the brain and heart. There are three main types of hypoxia:

  1. Anemic – this means a reduced ability for blood to carry oxygen, so less oxygen is distributed to the body
  2. Stagnant – this means blood flow is reduced or restricted
  3. Histotoxic – this means that tissues in the body aren’t able to properly use the oxygen delivered by the blood

There is also something called hypoxemia. Hypoxia and hypoxemia sound similar, but refer to two different conditions. Hypoxia is when the body tissues aren’t getting the oxygen they need. Hypoxemia is when there is a lack of oxygen in the arterial blood.[1]

Causes of hypoxia and anoxia

Causes of hypoxia – which can lead to anoxia – include:

  • Breathing problems that affect oxygen supply, like asthma or pneumonia
  • Carbon monoxide or other toxins in the body
  • Cardiac arrest or stroke
  • Events that restrict air, like choking or near-drowning
  • High altitudes where oxygen is low
  • Significant blood loss

Symptoms of hypoxia and anoxia

In the situations where oxygen loss is more immediate – like choking or cardiac issues – symptoms will show up quickly. In other cases, like high-altitude climbing or breathing problems, they may appear more gradually.

Mild symptoms of hypoxia and anoxia include:

  • Difficulty concentrating
  • Difficulty moving your body
  • Dizziness
  • Memory trouble
  • Slurred speech
  • Unexpected or strange headaches

More severe symptoms include:

  • Hallucinations
  • Loss of consciousness
  • Seizures

Diagnosis and treatment for hypoxia and anoxia

Diagnosis of hypoxia or anoxia is done based on symptoms, recent activity and hospital tests. These tests could include blood work, CT or MRI scans, or an electroencephalogram (EEG). The most important step is to increase the supply of oxygen in the most appropriate way based on the findings of the medical team. Once stabilized, tests will be done to determine if there is any brain damage that could cause cognitive, behavioural or mobility changes. These effects will vary case by case depending on the location and the severity of the injury. Rehabilitation and ongoing medical treatment may be necessary.[2]


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Non-Traumatic Brain Injury (nTBI)

An acquired brain injury (ABI) refers to any damage to the brain that occurs after birth and is not related to a congenital or a degenerative disease. There are two types of acquired brain injury: non-traumatic and traumatic.

Topics in this section include:

Non-traumatic brain injury

Non-traumatic acquired brain injuries are caused by something that happens inside the body, or a substance introduced into the body that damages brain tissues.

This includes:

A video on acquired brain injury

Acquired brain injury affects every part of a person’s life. This includes changes to your independence, abilities, work, and relationships with family, friends, and caregivers. Since a brain injury differs from person to person and recovery depends on several factors, in many cases it’s difficult to know what long-term behavioural, cognitive, physical or emotional effects there will be.

The effects of brain injury can be put in the following categories [1]:

Behavioural changes: The way a person acts or makes decisions can change after a brain injury. Behavioural changes include engaging in risky or impulsive behaviour, having difficulty with social and work relationships and isolation. This can be stressful and depending on the behaviour can cause safety concerns. Rehabilitation and medical teams will be able to provide practical tips for behaviour after a brain injury.

Cognitive changes: This is how the brain learns, processes information, forms memories and makes decisions. Challenges include communication, concentration, reading/writing, making decisions, and remembering things.

Emotional changes: after a brain injury, a person may experience new or different emotions, including depression, anxiety, and/or anger. Emotional changes are difficult to adjust to, and it’s important to have a support system of family, friends, and medical professionals.

Physical changes: In some cases, a brain injury will have physical effects. These effects include mobility challenges, headaches, fatigue, pain and sensory changes.

Is a concussion a brain injury?

A concussion is an acquired brain injury. Anyone who sustains a concussion can experience many of the physical, cognitive, emotional, and behavioural effects that accompany acquired brain injuries.

Concussion is also known as mild traumatic brain injury (mTBI) that has no neuroimaging findings. The term mild does not diminish the impacts that concussion can have on your health and activities of daily living (ADLs).

The challenges of prognosis

Prognosis means the likely path a disease or injury will take. In the case of acquired brain injury, prognosis is meant to give a best estimate of effects and recovery. Acquired brain injuries are all different, and there are a lot of factors that will impact a prognosis of recovery.

Factors that affect prognosis include:

  • Severity of injury
  • Previous injuries and existing conditions
  • Access to treatment
  • Age
  • Location of injury

Research shows that there is no system or set of variables that can accurately predict outcome for a single patient [2]. There is no definite timeline for recovery – it’s different for everyone. Doctors will update their prognosis as recovery progresses and provide next steps at the same time.

This section of our website covers the kinds of changes you may experience, management tips, and information on the kinds of tools and services that can help you and your family navigate living with brain injury.


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