Brief overview
- What is hypoxia? Insufficient oxygen supply in the body or in a part of the body.
- Causes: e.g. low oxygen pressure in the arterial blood due to disease (e.g. asthma, COPD, pneumonia), certain disorders of the blood circulation (right-left shunt), heart attack, thrombosis, reduced ability of the blood to transport oxygen, certain poisonings.
- When to see a doctor? Among other things, in case of bluish discolored mucous membranes (lips, nails, ears, tongue), blotchy redness of the skin, headache/dizziness, palpitations, shortness of breath
- Treatment: must always be treated by a physician; patient interview, blood analysis, if necessary determination of certain additional blood parameters (acidity of the blood, determination of the acid-base balance and pH value of the blood), possibly monitoring of the oxygen saturation in the blood and the heart rate
Hypoxia: Description
In hypoxia, the oxygen supply in the body or in a part of the body is insufficient. However, oxygen is vital for energy production in the cells, the so-called cell respiration – without sufficient oxygen supply, the cells are damaged.
Acute and chronic hypoxia
Acute hypoxia is caused, for example, by a sudden drop in aircraft pressure. More common is chronic hypoxia. It can be caused, for example, by a chronic lung disease such as COPD or by neuromuscular diseases such as myasthenia gravis or amyotrophic lateral sclerosis (ALS).
When there is not only too little oxygen (hypoxia) in a tissue, but none at all, physicians speak of anoxia.
Hypoxia in the womb (intrauterine hypoxia)
Even a child in the womb or during birth can suffer a dangerous lack of oxygen. If there is such a disturbance of the gas exchange in the placenta or lungs of the child, this is called asphyxia. The reason for the undersupply of oxygen to the fetus can be, for example, a functional disorder of the placenta (placental insufficiency), a heart disease of the mother or a fetal disease (such as heart defects or infections).
Hypoxia: Causes and possible diseases
Medical professionals distinguish between different types of hypoxia, which can occur in different ways:
Hypoxic (hypoxemic) hypoxia.
This form of hypoxia is the most common. It is characterized by insufficient oxygen pressure in the arterial blood, which means that the blood cannot be adequately oxygenated.
- Asthma
- COPD (chronic obstructive pulmonary disease)
- Pneumonia (lung inflammation)
- Pulmonary fibrosis ( hardening of the lungs)
- Pulmonary edema
- Pulmonary embolism
- Cystic fibrosis (cystic fibrosis)
- Pathological severe muscle weakness (myasthenia gravis)
- Amyotrophic lateral sclerosis (ALS)
Sometimes hypoxic hypoxia also results from disturbances in respiratory drive in the brain (in cases of intoxication with alcohol, sleeping pills, or anesthetics).
Another possible cause of hypoxic hypoxia is pulmonary right-to-left shunt. In this case, oxygen-depleted blood is added to the enriched blood, so that the overall oxygen content is reduced. A distinction is made between a functional and an anatomical right-to-left shunt, both of which lead to hypoxia:
Functional right-to-left shunt
In the case of a functional right-to-left shunt, part of the alveoli is supplied with blood but no longer ventilated. The circulating blood therefore remains deoxygenated. It mixes with the enriched blood from ventilated alveoli and thus reduces the overall oxygen content in the blood. The body tissue supplied with it receives too little oxygen – the result is hypoxia.
Anatomical right-left shunt
Anemic hypoxia
Oxygen is transported in the blood bound to hemoglobin – the red pigment in red blood cells (erythrocytes). In anemic hypoxia, the oxygen capacity of the blood (its ability to carry oxygen) is reduced.
This may be due to a deficiency of hemoglobin, such as may be caused by iron deficiency anemia (iron is a major component of hemoglobin).
A deficiency of red blood cells – for example, as a result of severe blood loss or a disorder of erythrocyte formation – may also result in Anemic Hypoxia.
In other cases of anemic hypoxia, oxygen binding to hemoglobin is impaired. The reason may be, for example, a congenital disorder of hemoglobin formation (such as congenital sickle cell anemia) or a condition called methemoglobinemia. In the latter, the blood level of methemoglobin is elevated. This is a derivative of hemoglobin that cannot bind oxygen. Methemoglobinemia can be congenital or caused, for example, by certain drugs (such as sulfonamide antibiotics) or toxins (such as nitrites, nitric oxide).
Ischemic hypoxia
When tissue or an organ has too little blood supply, too little oxygen is available to the cells. Possible causes of such ischemic hypoxia are, for example, a heart attack or another form of thrombosis (vessel occlusion due to a blood clot formed on site) as well as an embolism (vessel occlusion due to a blood clot washed up with the blood).
Cytotoxic (Histotoxic) Hypoxia.
In this form of hypoxia, enough oxygen does get into the cells. However, its utilization inside the cell for energy production (cellular respiration) is impaired. Possible causes are, for example, poisoning with cyanide (salt of hydrocyanic acid) or a bacterial toxin.
Hypoxia: When do you need to see a doctor?
Hypoxia often manifests itself in cyanosis: due to the undersupply of oxygen, the skin and mucous membranes turn bluish, especially in the area of the lips, nails, ears, oral mucosa and tongue. In the case of such cyanosis, one should notify the doctor.
Such symptoms often also occur with hypoxia of other causes.
Other possible signs of hypoxia are, for example, accelerated (tachypnea) or completely shallow breathing (hypopnea), increase in blood pressure, restlessness, anxiety, confusion and aggressiveness. In the event of such symptoms, a physician should be notified immediately.
Hypoxia: What does the doctor do?
In order to clarify hypoxia and its cause, the doctor will inquire about the complaints, possible accidents and underlying diseases and examine the patient. Blood gas analysis is used to measure, among other things, the levels of oxygen and carbon dioxide in the blood, and if carbon monoxide poisoning is suspected, the CO level is also measured. Other blood parameters can also be determined, such as the acidity (pH) of the blood, the acid-base balance and the hemoglobin level.
If necessary, the oxygen saturation in the blood and the heart rate are continuously monitored using pulse oximetry. For this purpose, a pulse oximeter, a small measuring device in the form of a clip, is attached to the patient’s finger.
Depending on the cause of the hypoxia or the corresponding suspicion, further examinations may follow.
How the doctor treats hypoxia
In addition, if possible, the cause of the oxygen deficiency (underlying disease, severe blood loss, poisoning, etc.) must be eliminated by initiating appropriate treatment.
Hypoxia: What can you do yourself?
Hypoxia must always be treated by a physician. He can clarify the cause and act accordingly.
