Introduction
Dehydration describes a lack of fluid in the body. Particularly in older people it is often caused by insufficient drinking quantities, but dehydration in children is also not uncommon due to frequent gastrointestinal infections and fever. The lack of fluid can also lead to electrolyte disorders and in the worst case to dehydration of the body with loss of consciousness.
Definiton
One speaks of dehydration (also: dehydration or dehydration) when the amount of fluid in the body decreases and there is a lack of water. Depending on the cause, the body’s water deficiency can assume different degrees of severity. A very strong dehydration can lead to dehydration (desiccosis) of the body.
Dehydration can be caused either by a too low fluid intake or a very high fluid loss. There are different forms of dehydration, which refer to the ratio of water and the minerals (electrolytes) in the body. A balanced ratio of water and electrolytes is very important in the body as it provides the prerequisite for all functions.
In the case of electrolytes, it is above all sodium that plays a decisive role in the regulation of the human water balance. In isotonic dehydration, sodium and water are absent to the same extent, whereas in the other two forms the ratio is shifted. In hypotonic dehydration it is mainly the sodium that is too little available, whereas in hypotonic dehydration there is an enormous lack of fluid and relatively too much sodium in the body.
Causes
The causes of a lack of water in the body can be very different. The most common cause is dehydration due to insufficient drinking quantities. This mainly affects older people, as they have a lower need to drink and feel thirsty.
But also young people, for example after hard physical work or at very high temperatures, can quickly suffer from dehydration if they do not drink enough to replace the sweaty water. In addition, diarrhoea and vomiting also lead relatively quickly to dehydration of the body, as does fever. High blood losses as a result of injury also lead to a lack of fluids in the body.
The fluid is the blood in the vessels. But organ diseases can also be the cause of dehydration, such as acute kidney failure or weakness of the adrenal glands, as well as diabetes. In these diseases there is a shift of fluid, especially out of the vessels and cells into the so-called extracellular space, i.e. the space between the cells. In patients who regularly take dehydrating drugs (diuretics), these can trigger dehydration if taken in excessive doses.
Symtoms
The first symptoms that occur when there is a lack of fluid in the body are usually headaches and a general feeling of weakness. The person affected usually feels thirsty, as the body recognises the lack of water and the brain sends out corresponding signals. The urine is also very dark in colour because the kidneys concentrate the urine to excrete less water.
Additional symptoms can occur as the disease progresses. These include dry skin and mucous membranes, which are noticeable in standing skin folds. In addition, the affected persons show increased dark circles under the eyes.
If the lack of water is not compensated, organic symptoms may be added. Tachycardia and low blood pressure (hypotension) are to be expected, as well as a stress reaction in which adrenaline leads to sweating. In later stages, cramps and clouding of consciousness up to unconsciousness may even occur.
If already 12 to 15% of the water in the body is missing, this leads to shock with circulatory weakness, which can even lead to coma. Children and infants are affected by dehydration much more often than adults. This is partly because they often drink too little, and partly because they often suffer from gastrointestinal infections that lead to diarrhoea and vomiting.
Even in the case of a long-lasting high fever, special attention should be paid to fluid intake. In principle, a fluid deficiency in children leads to the same symptoms as in adults. However, as children often cannot express how they feel, parents should pay attention to certain symptoms, especially if there is a gastrointestinal infection.
The child’s mucous membranes and skin become dry and standing skin folds can be observed when a skin area is pushed together with the hand. Also typical are sunken eyes with dark circles under the eyes. The sucking reflex in babies is weaker than usual and the number of eyelid blows is reduced, as is urine production, which can be seen in a dry diaper.
Weight loss also indicates a lack of fluid. If the child is already drinking, an increased feeling of thirst can often be detected. If signs of dehydration appear in a child or infant, or even fatigue and absence already indicate reduced consciousness, a paediatrician should be consulted immediately. You can find more information on this topic here: Diarrhoea in infants