Lack of oxygen in the blood medical term

Hypoxia is a condition defined by low oxygen in the tissues of your body. This is a medical emergency that can impact how well your body is able to function. There are several types of hypoxia that are caused by various conditions and situations.

This differs from hypoxemia, which is not having the proper amount of oxygen in the blood. The two terms are sometimes used interchangeably, but they are distinct conditions.

This article explains the different types of hypoxia. It also covers signs and symptoms of hypoxia, as well as potential causes and treatment options.

Types of Hypoxia

The different types of hypoxia showcase the variety of things that can go wrong when it comes to keeping tissues adequately oxygenated.

The main types of hypoxia include:

• Hypoxic hypoxia (hypoxemic hypoxia): There is a lack of oxygen in the blood flowing to the tissues.
• Hypemic hypoxia: Blood isn't able to carry oxygen as well as it should. Often this is because of an insufficient amount of healthy red blood cells. This leads to a lower supply of oxygen in the tissues.
• Stagnant/circulatory hypoxia: Poor blood flow leads to less oxygen available to the tissues. This may occur in one specific area or throughout the whole body.
• Histiotoxic hypoxia: Enough oxygen is taken in through the lungs and delivered to the tissues, but the body has difficulty using it.
• Cytopathic hypoxia: Oxygen is able to be used properly by the tissues, but there is a higher demand for oxygen than usual.

Click Play to Learn the Different Types of Hypoxia

The signs and symptoms of hypoxia vary from person to person.

They may include:

• Confusion
• Fatigue, or low energy
• Difficulty with concentration and judgment
• Slurred speech
• Hot flashes, or a sudden feeling of intense heat
• Lack of coordination
  
• Fainting or dizziness
  
• Shortness of breath
• Tingling or warm sensations in the body
• Visual changes like tunnel vision, or difficulty seeing to the side
• Rapid heart rate and high blood pressure
• Rapid breathing
• Euphoria and a sense of well-being
• Headache
• Bluish tinge to skin

Complications

The brain and the heart are the organs most affected by hypoxia.

Long-term, milder hypoxia can cause serious damage as the body tries to adapt to the lower oxygen levels. Research indicates that it may play a significant role in:

• Tumor growth and progression in cancer
• Cancer drug resistance
• Worsening certain heart conditions
• The loss of kidney functioning

If a case is severe, damage can begin within minutes of hypoxia occurring. The following can occur as a result:

• Seizures, or uncontrollable brain disturbances that can cause involuntary movements and changes in consciousness
• Coma, an extended period of unconsciousness
• Death

Why Hypoxia Occurs

Different types of hypoxia can occur due to certain circumstances and because of some medical conditions.

Hypoxic hypoxia can be caused by:

• High altitudes and lower levels of oxygen in the air
• Shallow breathing or breathing that is too slow
• Pulmonary edema, which is when the lungs fill with fluid
• Ventilation-perfusion mismatch, which occurs when parts of the lungs get enough oxygen but no blood flow, or vice versa
• Asthma, a lung condition that makes it difficult to breathe

Causes of hypemic hypoxia may include:

• Any type of anemia, such as iron deficiency anemia and chemotherapy-induced anemia, which is a common side effect of this treatment
• Bleeding in large amounts (externally or internally)
• Carbon monoxide poisoning

Causes of circulatory/stagnant hypoxia may include:

• Edema, or the swelling of the tissues, which can limit the ability of oxygen in the blood from effectively reaching the tissues
• A blood clot, which blocks the flow of blood carrying oxygen
• Shock, a life-threatening condition where the body has a sudden drop in proper blood flow
• A stroke, which occurs when a blood clot blocks blood flow and oxygen to the brain

Histiotoxic hypoxia can be caused by cyanide and other poisons.

Cytopathic hypoxia may be caused by:

• Sepsis, a life-threatening condition where an infection moves into the bloodstream
• Systemic inflammatory response syndrome (SIRS), which describes inflammation throughout the entire body

Diagnosis

There are different tests your healthcare provider may order to confirm hypoxia and better understand why its occurring.

Some tests may include:

• Oximetry, a test that uses a sensor placed on your body to check the oxygen level in your blood to help diagnose hypoxia
• Arterial blood gases, a blood test that helps diagnose hypoxia and checks the amount of oxygen and carbon dioxide in your blood, as well as your breathing and kidney functioning
• A complete blood count (CBC), a blood test that helps diagnose causes of hypoxia such as anemia and signs of infection
  
• Imaging tests, like an X-ray or a computed tomography (CT), of your chest that help diagnose causes of hypoxia such as lung conditions or infection
• Magnetic resonance imaging (MRI) of your head that help diagnose brain related causes of hypoxia such as tumors, bleeds, or strokes
• An electrocardiogram (EKG), a non-invasive test that helps diagnose causes of hypoxia and looks for signs of heart damage or an irregular heartbeat
• Echocardiogram, an ultrasound imaging test that helps diagnose causes of hypoxia by checking how well the heart is functioning

Hypoxia Treatment

The treatment of hypoxia depends on the specific underlying cause.

Treatment may include oxygen therapy, which delivers oxygen to you through a mask or tubes in your nose.

In some cases, mechanical ventilation may be needed to do the work of breathing for a person who isn't taking in enough oxygen.

When necessary, medications may be used to treat with the underlying condition.

Other treatments may be given depending on the underlying cause.

Summary

Hypoxia describes having low oxygen in the tissues of your body. There are four main types of hypoxia that can be triggered by various medical conditions or circumstances.

Symptoms of hypoxia will vary from person to person. Both severe hypoxia and mild, long-term hypoxia can lead to serious damage. Treatment depends on your specific needs and if there is an underlying condition.

Frequently Asked Questions

• What oxygen level is considered hypoxia?

  A pulse oximeter reading below 92% could indicate hypoxia.

• Can you live with hypoxia?

  Even mild forms of hypoxia can lead to serious issues and require medical treatment.

• What is silent or happy hypoxia?

  This describes when an individual has low oxygen levels, but is able to breathe normally and doesn't have any other symptoms. For instance, Covid-19 is especially likely to cause silent hypoxia.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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By Lynne Eldridge, MD
 Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."

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