Dehydration is a deficiency of water in the body.
Dehydration occurs when water is eliminated from the body more than the volume ingested. Water deficiency generally causes an increase in sodium concentration in the blood. Vomiting, diarrhea, the use of diuretics (medicines that excrete excessive amounts of salt and water in the kidneys), excessive heat, fever and a decrease in water consumption can lead to dehydration. Some diseases, such as diabetes mellitus, diabetes insipidus and Addison's disease, can cause dehydration due to the excessive water loss that characterizes them.
First, dehydration stimulates the brain's thirst centers, causing more fluid to be drunk. If consumption fails to compensate for lost water, dehydration worsens, perspiration decreases and less urine is produced. Water travels from the vast internal deposit of cells to the blood. If dehydration does not improve, body tissues begin to dry. Eventually, the cells begin to shrink and function improperly. Brain cells are among the most prone to dehydration, so one of the main signs of severity is mental confusion, which can progress to coma.
The most common causes of dehydration, such as excessive sweating, vomiting and diarrhea, cause a loss of electrolytes, especially sodium and potassium, as well as water.
Hence dehydration is often accompanied by an electrolyte deficiency.
In this case, water does not move easily from the large internal deposit of cells to the blood. Therefore, the volume of circulating water in the blood is even smaller. There may be a drop in blood pressure, causing slight nausea or a feeling of impending loss of consciousness, especially when standing (orthostatic hypotension). If the loss of water and electrolytes continues, blood pressure can fall dangerously and cause a shock with severe damage to many internal organs, such as the kidneys, liver and brain.
In case of mild dehydration, drinking natural water may be sufficient. However, when there has been a loss of water and electrolytes, the salt (especially sodium and potassium) should also be replaced. Some isotonic drinks to replace salts (electrolytes) lost during intense exercise. These drinks can be used to prevent or cure mild dehydration. Drinking a large amount of fluid and consuming a small amount of additional salt during or after exercise is also an effective method. People with heart or kidney problems should consult their doctor to safely replace their fluid before beginning any exercise.
If a fall in blood pressure causes a shock or a threat of shock, solutions containing sodium chloride are administered intravenously. Intravenous fluids are delivered rapidly at first and then more slowly as physical condition improves. The root cause of dehydration should always be treated. For example, in case of diarrhea, you may need to take medicines to treat or stop it, and replace fluids. When the kidneys are excreting too much water due to an antidiuretic hormone deficiency (as may be the case in diabetes insipidus), chronic treatment with synthetic antidiuretic hormone may be necessary. Once the cause is resolved, individuals in the recovery phase are controlled to ensure that oral fluid consumption is again adequate to maintain hydration.