Shock – acute and life-threatening

During a shock, the blood circulation fails. As a result, the system organs do not receive enough oxygen and waste products, such as carbon dioxide, accumulate. All bodily functions are on the verge of collapse, with one organ after another failing. This life-threatening, acute situation requires immediate medical intervention. Recognizing the early stages of shock is extremely important to prevent the condition from becoming ‘irreversible’, where recovery is no longer possible.


  • Reversible and irreversible shock
  • What happens in shock?
  • Heart
  • Lungs
  • Brain
  • Liver
  • Kidneys
  • Signs (symptoms) of shock
  • Causes of shock
  • Seek medical attention immediately

Reversible and irreversible shock

Shock means that the blood circulation is disturbed. The vascular filling or blood circulation is then inadequate, as a result of which the body cells can no longer function adequately, partly due to a lack of oxygen. Especially during shock it becomes clear how vulnerable the cells are. After all, they are completely dependent on both an effective oxygen supply and the supply and removal of nutrients and waste products, such as carbon dioxide. If blood circulation stops, the cells immediately suffer.

Intensive care / Source: Wmschupbach, Flickr (CC BY-2.0)

Blood circulation
The brain in particular, but also other organs, cannot survive for long without oxygen. If blood circulation recovers in time, there is a reversible shock. For example, if the brain is deprived of oxygen for too long, the brain cells will die. The shock is then irreversible. Irreparable damage occurs that leads to death.

What happens in shock?

Someone in shock will need to be resuscitated (restoring vital functions) immediately. Otherwise, the reversible shock progresses into a fatal, irreversible form, in which the functions of the system organs are at stake. Thanks to all kinds of compensatory mechanisms, these organs will be kept at bay for the longest time during a shock. This means that blood circulation is maintained longer than, for example, in the skin, muscles or in the gastrointestinal tract. The functional preservation of these organs is therefore of decisive importance to ensure that the shock does not become irreversible or that it is postponed for as long as possible pending timely treatment. These vital organs are:


If the heart cells receive too little oxygen and the pumping function of the heart is reduced, the already unstable blood circulation will deteriorate even more.


The lungs ensure the absorption of oxygen and the release of carbon dioxide (carbon dioxide). It is therefore important that, in addition to the heart, the lungs continue to work for as long as possible. In short, the body does everything it can to prevent the shock from becoming irreversible.


Once the brain cells are affected, the nerve connections to and from the organs fail.


This organ produces vital substances and has a very important detoxifying effect. If the liver fails during a shock, important raw materials for cell metabolism are no longer supplied. More and more waste products will accumulate in the body, resulting in metabolic acidosis.


Due to the dysfunction of the kidneys, acid waste products will not be removed and the fluid and salt balance (electrolytes) will become unsatisfactory, resulting in uremia (kidney poisoning) and acidosis (acidification).

Signs (symptoms) of shock

Shock can have various causes. The symptoms of a crashed circulatory system, on the other hand, are very characteristic and virtually the same in all types of shock , except perhaps in septic shock. These symptoms include:

Source: Clker Free Vector Images, Pixabay

Paleness, cold skin.
Blood circulation is minimal, hence the pale skin. The blood vessels in the skin are practically closed for circulation in the vital organs, such as the heart, lungs and brain.

The skin is clammy, except in the case of warm shock (septic shock). Sweating is caused by paralysis of the nerve pathways leading to the sweat glands. It is a sign that the shock has entered a serious phase.

Sunken face
This is because the moisture is extracted from the skin. Fluid that enters the bloodstream to maintain vascular volume.

Fast heart rate (soft pulse or wire pulse) and low blood pressure.
Due to a faster heart rate, relatively more blood is pumped through the vascular system. This keeps blood circulation somewhat normal. In a cardiogenic (cardiac) shock, the pump function is limited, causing the heart to beat faster in compensation. This also applies to other forms of shock, for example if too little venous blood is pumped back to the heart due to excessive blood loss. The blood pressure, especially the upper pressure (systole), is then low and the pulse feels weak. In the event of bleeding, there will be too little blood volume to fill the vascular system. Too low blood pressure is always a sign that the shock is becoming irreversible.

Fast breathing
By breathing faster, the body tries to eliminate the oxygen shortage. It is also a compensation mechanism.

Little or no urine production
The kidneys try to keep as much fluid as possible in the bloodstream to stabilize blood pressure, including by producing more hormones (including renin). However, as blood pressure continues to decrease, the kidneys can filter less effectively. Oliguria then develops (less than 25 ml of urine per hour). Ultimately, urine production virtually ceases (anuria, less than 10 ml per hour) and the body poisons itself (uremia and acidosis).

Clear consciousness
Consciousness often remains remarkably good until the end phase of the shock, which is curious in itself. One can even have a normal conversation with the person in question, although he or she misses what is happening around him. Even when things get hectic in clinical circumstances, such as quickly inserting an IV, or doctors and nurses are otherwise busy trying to keep him alive.

Source: FaceMePLS, Flickr (CC BY-2.0)

Causes of shock

There are four factors that maintain blood circulation. In shock, one of these aspects is deficient, for example due to severe bleeding , which compromises the vascular filling. And in cardiogenic or cardiac shock, the pumping function of the heart leaves much to be desired, such as in congestive heart failure (heart failure) and atrial fibrillation. The size and effectiveness of the vascular system also play a role. Derived from these four factors, there are four causes of shock:

  1. Inadequate pumping function of the heart, such as in cardiogenic (cardiac) shock.
  2. Insufficient vascular filling, such as with severe bleeding.
  3. Vasodilation while blood volume remains the same. This makes it appear as if there is ‘too little’ blood flowing through the vessels, such as in anaphylactic shock. This is also called ‘warm shock’, which is usually toxic-infectious in nature.
  4. Blood pooling in a certain vascular area. This leaves too little blood to adequately fill the rest of the bloodstream. This is called distribution key shock, as sometimes occurs with peritonitis (inflammation of the peritoneum) and with bacterial infections, in which a lot of blood collects in the vascular system of the gastrointestinal tract.

Seek medical attention immediately

It goes without saying that the cause of the shock must be found as quickly as possible. Only then is adequate treatment possible. The doctor must find out what is causing the shock, this collapse of blood circulation. It could be a pulmonary embolism, but also an acute myocardial infarction. With a serious infection, vasodilation shock may occur, resulting in sepsis (septic shock).

Recognizing symptoms
It is important to realize that shock is an acute, life-threatening situation. In fact, every layman should memorize the above-mentioned symptoms. Someone who is in shock is fortunate if there is someone around who understands the seriousness of it and immediately seeks medical help.

read more

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  • Checklist – is fainting serious?
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  • Heat exhaustion and heat stroke – who is susceptible to them?
  • Heart in distress – cardiogenic (cardiac) shock