What Causes Anemic Hypoxia?

Anemic hypoxia is a blood defect that occurs when the blood’s ability to carry oxygen decreases. Causes include altitude sickness, carbon monoxide poisoning, different types of anemia, hemorrhages, and hopoventialtion.

One of the primary functions of your cardiorespiratory system is to ensure that all your body parts receive oxygen. Hypoxia is a biological condition where the tissues are starved of oxygen.

Anemic hypoxia occurs when the blood’s ability to carry oxygen decreases. This blood defect means that there are fewer hemoglobin molecules (or oxygen-binding sites) available within the blood for binding oxygen.

Anemic hypoxia symptoms can vary from person to person, as well as by how long the symptoms have been present. They include: 

• Blue lips 
• Confusion
• Dizziness 
• Fainting (syncope)
• Headaches
• Hypertension
• Lack of coordination
• Lethargy
• Rapid heart rate 
• Shortness of breath
• Tingling sensation in arms and legs
• Visual blurriness 

Hypoxia literally means “low oxygen,” and it can affect a specific organ (tissue hypoxia) or the entire body (generalized hypoxia). There are different types of hypoxia or reasons that there is not enough oxygen in the body tissues. The other types of hypoxia are:

Histotoxic hypoxia

This condition is when tissues get the right amount of oxygen but can’t use it. Cyanide poisoning, for example, causes histotoxic hypoxia because it blocks the mitochondria from consuming the oxygen. 

Hypoxic hypoxia

With this type of hypoxia, the tissues in the body don’t have enough oxygen because there is an overall lack of oxygen in the blood. Hypoxic hypoxia is commonly caused by not breathing enough, for example.

Stagnant hypoxia

Stagnant hypoxia refers to situations where there is inadequate blood flow, usually caused by shock, fainting, or other “low-flow” states.

With anemic hypoxia, oxygen you breathe in can’t adequately reach all the areas of the body because of low hemoglobin levels in the blood. This results in a lower supply of oxygen to your tissues and organs. Causes for anemic hypoxia can include:

• Altitude sickness, where there are not enough oxygen molecules at very high altitudes, which can keep the lungs from breathing in enough oxygen
• Carbon monoxide poisoning that prevents hemoglobin from binding to oxygen
• Different types of anemia like chemotherapy-induced anemia, iron deficiency anemia, or pernicious anemia
• Hemorrhages from injuries, either internal or external 
• Hypoventilation, which is the body simply not breathing enough
• When hemoglobin converts into methemoglobin, making it impossible to bind oxygen

Your doctor has many options to assess the oxygen levels in your blood and determine if you have hypoxia. Laboratory tests help identify the cause of your symptoms. Some of the tests for hypoxia include:

• Arterial blood gases to test your respiratory and metabolic status
• Blood tests to look for anemia (low red blood cell count) or signs of infection
• Bronchoscopy to look for any sign of obstruction in the airways, such as a tumor
• Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) of your head to look for brain abnormalities that could suppress breathing such as tumors, bleeds, or strokes
• Echocardiogram that can observe the heart and look for damage or abnormalities in the heart or heart valves
• Electrocardiogram (EKG) to look for any signs of an irregular heartbeat or other heart damage
• Oximeter to track the oxygen level in your blood
• X-ray or a CT of your chest to look for lung diseases or infection

There are several factors to consider when identifying the best treatment for anemic hypoxia. Once the cause is identified, you can start with the appropriate medications, procedures, and therapies. 

Doctors commonly recommend oxygen therapy, especially if you have shortness of breath or other moderate to severe symptoms of hypoxia. If your symptoms are severe, your doctor will likely recommend that you get help breathing with a mechanical ventilator.

In very severe, life-threatening cases, a hyperbaric oxygen treatment can be used. The higher levels of oxygen provided under pressure can sometimes improve blood flow and distribution of oxygen throughout the body in a way that is otherwise not possible.