Diseases

Dehydration

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Dehydration is a deficit of total body water,[1] with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mild dehydration can also be caused by immersion diuresis, which may increase risk of decompression sickness in divers.

SYMPTOMS

Thirst isn't always a reliable early indicator of the body's need for water. Many people, particularly older adults, don't feel thirsty until they're already dehydrated. That's why it's important to increase water intake during hot weather or when you're ill.

The signs and symptoms of dehydration also may differ by age.

Infant or young child
dry mouth and tongue
no tears when crying
no wet diapers for three hours
sunken eyes, cheeks
sunken soft spot on top of skull
listlessness or irritability
Adult
extreme thirst
less frequent urination
dark-colored urine
fatigue
dizziness
confusion

CAUSES

Diarrhea, vomiting. Severe, acute diarrhea — that is, diarrhea that comes on suddenly and violently — can cause a tremendous loss of water and electrolytes in a short amount of time. If you have vomiting along with diarrhea, you lose even more fluids and minerals.
Fever. In General, the higher your fever, the more dehydrated you may become. The problem worsens if you have a fever in addition to diarrhea and vomiting.
Excessive sweating. You Lose water when you sweat. If you do vigorous activity and don't replace fluids as you go along, you can become dehydrated. Hot, humid weather increases the amount you sweat and the amount of fluid you lose.
Increased urination. This May be due to undiagnosed or uncontrolled diabetes. Certain medications, such as diuretics and some blood pressure medications, also can lead to dehydration, generally because they cause you to urinate more.