Decompression sickness, or caisson disease (Morbus Caisson, DCS Decompression sickness), is a group of symptoms appearing in people exposed to rapid changes in pressure in the environment. What are the symptoms of caisson disease? What are the effects of decompression sickness? How can it be avoided?

Decompression sickness( caisson disease , Morbus Caisson, DCS Decompression sickness) occurs as a result of a sharp drop in external pressure (affecting the body human), which occurs, for example, when a diver ascends quickly. The effects of this can be dramatic and even lead to death. Although the first descriptions of the symptoms of this disease come from the nineteenth century and concerned construction workers employed in the construction of bridges, examples of caisson disease can also be found today, especially due to the constantly growing popularity of diving and the commercialization of underwater tourism.

The name "caisson disease" comes from caissons - that is steel crates, which were used for underwater works, eg in the construction of bridges or harbors. The appropriate tightness of the boxes and the high pressure prevailing in them (often many times higher than the atmospheric pressure) prevented the inflow of water inside them. As a result, employees locked in caissons could work under water for a long time. At the same time, the period of their exposure to unfavorable environmental conditions was prolonged (high pressures are not standard conditions for our body). The key moment was the emergence of workers after their work was finished. Rapid pressure drops while surfacing above the water surface caused a number of changes in the body. Symptoms frequently observed with these activities, such as muscle pain, joint pain or itching of the skin, have been combined with the type of work performed over time and have been called the caisson disease

Decompression sickness (caisson): causes

When diving to great depths, your body is exposed to high hydrostatic pressure (ambient pressure). According to Henry's physical law, an increase in pressure increases the solubility of gases in fluids. This principle is also reflected in our body, where the amount of gases dissolved in the blood begins to increase rapidly. This is especially truenitrogen, found in large amounts in the breathing mixture (as much as 78%), which additionally dissolves very well in the blood. This gas will not only be deposited in the blood, but also in most body tissues.

The amount of nitrogen "stored" in tissues depends, among others, on the depth at which the diver was and the time he spent under the water. Nitrogen, unlike oxygen or carbon monoxide, is not involved in metabolic processes, and the only way to eliminate it from the body after being stored in the tissues is to exhale through the lungs.

Nitrogen deposition in tissues is also dependent on the blood supply to the tissues and the content of fats in them. Due to their good blood supply, the gas saturation of the muscle tissue and the brain will take place much faster than in the case of adipose tissue. Adipose tissue is characterized by a much greater ability to concentrate gases (nitrogen solubility in adipose tissue is much higher). The organs with poor blood supply, where the amount of nitrogen stored will be smaller, include, among others, bone tissue and the joints that make up the locomotor system. Symptoms of the caisson disease mainly concern the mentioned body tissues.

During the diver's ascent, as the pressure begins to decrease, all prior processes will occur in the opposite way, albeit at a comparable speed. The pressure drop also causes the gas solubility to drop. The gas previously dissolved in the tissues is released in the form of bubbles. The stored nitrogen can only be removed by getting the bubbles formed into the blood and with it into the lungs. Thanks to the exchange of respiratory gases in the lungs, it will leave the body.

It is in the emerging nitrogen bubbles that the cause of the symptoms that can be observed in people suffering from decompression sickness should be sought. Gas bubbles have the ability to mechanically damage tissues, damage blood vessels, as well as create blockages in them. The final step may be to occlude the vessel and interrupt blood supply to the organs. It then becomes impossible to supply them with oxygen. Tissues become hypoxic, metabolic processes are disrupted and cells die. In brain and muscle tissue, which are particularly sensitive to oxygen deficiency, these changes will occur very quickly, while in adipose tissue - much slower.

Decompression sickness: types, symptoms

There are basically 2 types of decompression sickness. Due to the type of tissues it touches, they can overlap with each other orbe a mixed form of the disease:

  • Type 1 caisson disease

The symptoms of the disease concern skin, bones, joints, muscles:

  • weakness or fatigue
  • itchy skin
  • numerous bluish-red tints appearing
  • diffuse muscle and joint pain
  • restriction of mobility

Peripheral joints - knee, shoulder or elbow - are most often affected. In patients, a bent (shrunken), sparing posture is noticeable. Massive swelling resulting from the closure of small blood and lymph vessels. Most symptoms appear within a few hours of surfacing, although symptoms may appear up to 24 hours after the end of the dive.

  • Type 2 of caisson disease

In this case, the gas bubbles that form form symptoms from organs such as the brain, middle ear, and spinal cord. This type also includes vascular embolisms (blockages) caused by gas bubbles. If the gas blockages affect the main vessels of the body, the result may be:

  • partial or total loss of consciousness
  • stop breathing
  • sensory disturbances, paralysis, up to hemiparesis.

Closing the vessels of the spinal cord leads to bilateral paresis, impaired urination and stool. Symptoms from the middle ear appear quite quickly in the form of:

  • nausea
  • vomiting
  • tinnitus
  • dizziness

In addition, other symptoms related to organ ischemia may occur in caisson disease. Speech here, among others about aseptic bone necrosis, hearing or sight damage.

It should be emphasized that untreated or too late detection of the caisson disease can lead to death.

It is impossible to accurately predict whether the effects of the caisson disease will be permanent and the impairment of the organ function will be reversible. The prognosis depends mainly on the size, location and type of tissue damage, which should be considered due to the individual conditions of the organism and the size of the injury.

Decompression sickness: risk factors

  • acute infections of the upper respiratory tract, colds, asthma
  • nicotine
  • dehydration e.g. from previous diarrhea
  • fever
  • alcoholism
  • diabetes
  • older age
  • hypertension
  • hypothermia

The risk increases with repeated diving attempts. During each descent into the water, nitrogen is stored, whichcomplete elimination takes place after a few days.

Decompression sickness: prevention

With the rapid development of underwater tourism and the wide range of travel agencies offering extreme adventures to people who previously could not afford it, the risk of decompression sickness increases.

For all divers, the ascent rate should also be tightly controlled.

People who decide to dive should undergo appropriate training courses organized by professionals, diving schools with appropriate licenses, etc. In the case of group dives, we will always be supervised by a person with appropriate knowledge. It is very important for the diver to know the exact diving plan beforehand, the depth to which the dive is planned, and to calculate the pressure at the descent depth using appropriate calculators in order to select the appropriate type of breathing mixture.

Important

If we witness an accident while diving, the same rules apply as in the case of life-threatening situations. These are the so-called BLS (Basic Life Support), i.e. basic life support procedures.

1. First of all, we check whether it is safe to help ourselves. For example, we don't jump into the water to pull someone out, if we can't swim ourselves.

2. If we are on the shore, we check the victim's consciousness.

3. We're calling for help.

4. We clear the respiratory tract and check if the breathing is correct.

5. If the victim is not breathing or reacting properly, we call for help on 112 or 999 and conduct CPR until the ambulance arrives or the victim recovers.

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