Cerebral Hypoxia: Types And Causes

Cerebral hypoxia occurs when less oxygen flows to the brain than what is considered normal. A normal flow of oxygen allows the brain to function properly, according to the needs of the body.

It should be clear that the brain is an organ whose functions must not stop. Different parts of the brain are activated at different times, but the rest of the components of the human body depend on their correct functioning.

Due to their constant functioning, the brain consumes a large amount of oxygen. In addition, oxygen comes through the arteries that distribute the blood upwards from the neck. So if the blood decreases, there will also be less oxygen.

A lack of oxygen has major consequences for the brain. The cells that make up this organ begin to die if they don’t get oxygen for about five minutes. This is known as a cerebral infarction, and shows how severe cerebral hypoxia can be.

The Causes of Cerebral Hypoxia

The causes behind cerebral hypoxia vary. Sometimes it is only due to a decrease in oxygen reaching the skull area. Other times, however, in addition to the oxygen decrease, there is also a decrease in blood flow, with all the consequences that entails.

A number of causes

• Elevations above sea level lead to a decrease in the oxygen available to the brain to function. This is the altitude sickness that accompanies the practice of sports such as climbing and mountaineering.

• Carbon monoxide is the leading cause of gas poisoning. When this occurs, the oxygen in the blood is replaced by carbon monoxide. In this way, the cells throughout the body get an element that they cannot use for their metabolism.
• Some pathologies, such as amyotrophic lateral sclerosis, attack the respiratory center of the brain, paralyzing the respiratory muscles. When the breathing mechanism fails, less oxygen gets in. This causes a kind of suffocating mechanism.
• Choking, one way or another, both cause cerebral hypoxia. Strangulation, drowning with liquids, and inhaling the smoke from a fire are some forms of suffocation.

• Arterial hypotension occurs when blood pressure becomes too low and insufficient to reach all body tissues, especially if they are far from the heart. The brain is one of the areas affected by this.
• Any heart condition that limits your normal capacity and pace can lead to cerebral hypoxia. It can be an acute event, such as a heart attack, or a chronic problem such as arrhythmias.
• Strokes cause cerebral hypoxia in certain areas. This can be caused by blockage of a cerebral artery by a clot, but also by breaking some of the blood vessels in the brain, causing them to bleed.

Types

You can classify cerebral hypoxia according to the affected brain area. Some hypoxic episodes only affect the cells of a certain point in the brain, while there are times when the general flow stops.

So, these are the types of cerebral hypoxia:

• focal. In this case, the cerebral hypoxia is punctual. The classic example is a stroke that develops in a clot blocking a cerebral artery.
• Diffuse. This is a decrease in the flow of oxygen that takes place evenly in the brain, without it becoming too severe. The functions of the brain cells decrease, but an infarction is rare.

• global. In this case, the decrease affects the whole brain. The lack of oxygen is so noticeable that the cells die. The subsequent symptoms depend on the brain region affected.
• solid. This is the maximum expression of cerebral hypoxia, which infarcts large areas of the brain at the same time, endangering subsequent recovery and life.

Symptoms of cerebral hypoxia

While the symptoms of cerebral hypoxia depend on how long the lack of oxygen lasts, some of its signs are quite distinctive. As we mentioned above, hypoxia lasting a few seconds may not pose any danger, but if it lasts for five minutes, a stroke is bound to follow.

The consequences of temporary hypoxia can be as follows:

• lack of attention
• a form of amnesia
• strange sensations in the limbs of the body
• speech problems

There may also be limited movement, similar to paralysis.

If the lack of oxygen lasts longer, there will be later attacks, which can cause the person to pass out and even go into a coma. At this point, urgent care is vital, as the person needs emergency first aid from an expert immediately.

If the cerebral hypoxia lasts longer than five minutes, a heart attack will follow. A small heart attack can lead to recovery with rehabilitation, but a major heart attack can cause death of the entire brain.

So you should see a doctor if you experience neurological symptoms. Also, if someone faints and doesn’t react immediately or has convulsions, it is the right step to contact the emergency room who can help him or her quickly.