Dehydration

Information and facts about Nutrition.

Dehydration is the removal of water (hydor in ancient Greek) from an object. Medically, dehydration is a serious and potentially life-threatening condition in which the body contains an insufficient volume of water for normal functioning.

In non-medical usage, there are many methods of dehydration, with the most common being the application of dry heated air. This causes evaporation of the surface water, which is replaced by water internally. Less common methods include freeze drying and supercritical drying. Drying is often used as a method of food preservation and is also used to obtain absolute alcohol.

Medical causes of dehydration
In humans, dehydration can be caused by a wide range of diseases and states that impair water homeostasis in the body. These include:

external or stress-related causes
blood loss or hypotension due to physical trauma
diarrhea
hyperthermia
shock
prolonged physical activity without consuming adequate water, especially in a hot environment
survival situations, especially desert survival conditions
vomiting
infectious diseases
cholera
gastroenteritis
shigellosis
yellow fever
malnutrition
electrolyte imbalance
hypernatremia (also caused by dehydration)
hyponatremia, especially from restricted salt diets
excessive consumption of alcohol
fasting
patient refusal of nutrition and hydration
other causes of obligate water loss
severe hyperglycemia, especially in diabetes
glucosuria

Symptoms and prognosis
Symptoms may include headaches similar to what is experienced as a hangover, a sudden episode of visual snow, decreased blood pressure (hypotension), and dizziness or fainting when standing up due to orthostatic hypotension. Untreated dehydration generally results in delirium, unconsciousness, and death.

Treatment
Correction of a dehydrated state is accomplished by the replenishment of necessary water and electrolytes (rehydration). Even in the case of serious lack of fresh water (e.g. at sea or in a desert), drinking seawater or urine does not help, nor does the consumption of alcohol.

When dehydrated, unnecessary sweating should be avoided, as it wastes water. If there is only dry food, it is better not to eat, as water is necessary for digestion. The best treatment for minor dehydration is consumption of Gatorade or a pediatric electrolyte formula such as pedialyte. For severe cases of dehydration where fainting, unconsciousness, or any other severely inhibiting symptom is present (the patient is incapable of standing or thinking clearly), emergency attention is required. Fluids will be given through an IV, and within a few hours, the patient will return to normal unless a complication occurred.

Avoiding dehydration
A person's body loses, during an average day in a temperate climate such as the United Kingdom, approximately 2.5 litres of water. This can be through the lungs as water vapor, through the skin as sweat, or through the kidneys as urine. Some (a less significant amount, in the absence of diarrhea) is also lost through the bowels.

When taking vigorous exercise or in a hot environment, it is easy to lose twice this amount. Heavy exercise in high temperatures could cause the loss of over 2.5 litres of fluid per hour, which exceeds the body's absorptive capacity.

Ethical concerns
Judge Lynch of the Massachusetts Supreme Judicial Court argued that death by dehydration symptoms was ‘"cruel and violent"’ in his opinion on the 1986 Brophy case:

The mouth would dry out and become caked or coated with thick material.
The lips would become parched and cracked.
The tongue would swell, and might crack.
The eyes would recede back into their orbits and the cheeks would become hollow.
The lining of the nose might crack and cause the nose to bleed.
The skin would hang loose on the body and become dry and scaly.
The urine would become highly concentrated, leading to burning of the bladder.
The lining of the stomach would dry out and the sufferer would experience dry heaves and vomiting.
The body temperature would become very high.
The brain cells would dry out, causing convulsions.
The respiratory tract would dry out, and the thick secretions that would result could plug the lungs and cause death.
At some point within five days to three weeks, the major organs, including the lungs, heart, and brain, would give out and the patient would die.

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All information published on this web site is for information purposes only. The content of this web site should not be used for a conclusive diagnosis or for choosing a treatment. The content on this site has been provided as a guideline and general information it is not intended to replace professional medical care. In all serious cases it is advisable to recieve attention from a qualified medical practitioner. All text is available under the terms of the GNU free documentation license.