Dehydration means your body does not have as much water and fluids as it should.
Dehydration can be mild, moderate, or severe based on how much of the body's fluid is lost or not replenished. When it is severe, dehydration is a life-threatening emergency.
Dehydration can be caused by losing too much fluid, not drinking enough water or fluids, or both.
Your body may lose too much fluids from:
You might not drink enough fluids because of:
Dehydration in sick children is often a combination of refusing to eat or drink anything and losing fluid from vomiting, diarrhea, or fever.
Infants and children are more likely to become dehydrated than adults because they weigh less and their bodies turn over water and electrolytes more quickly. The elderly and people with illnesses are also at higher risk.
You may also have vomiting, diarrhea, or the feeling that you "can't keep anything down." All of these can be causing the dehydration.
A physical examination may also show signs of:
Other tests may be done to determine the cause of the dehydration (for example, blood sugar level to check for diabetes).
Drinking fluids is usually enough for mild dehydration. It is better to drink small amounts of fluid often (using a teaspoon or syringe for an infant or child), instead of trying to force large amounts of fluid at one time. Drinking too much fluid at once can bring on more vomiting.
Electrolyte solutions or freezer pops are very effective. These are available at pharmacies. Sports drinks contain a lot of sugar and can cause or worsen diarrhea. In infants and children, avoid using water as the primary replacement fluid.
Intravenous fluids and a hospital stay may be needed for moderate to severe dehydration. The health care provider will try to identify and then treat the cause of the dehydration.
See also: Heat emergencies
When dehydration is found and treated quickly, the outcome is usually good.
Untreated severe dehydration may lead to:
Call 911 if you or your child have the following symptoms:
Call your health care provider right away if you or your child has any of the following symptoms:
Call your health care provider if you are not sure whether you are giving your child enough fluids.
Also call your health care provider if:
Even when you are healthy, drink plenty of fluids every day. Drink more when the weather is hot or you are exercising.
Carefully monitor someone who is ill, especially an infant, child, or older adult. If you believe that the person is getting dehydrated, call your health care provider before the person becomes dehydrated. Begin fluid replacement as soon as vomiting and diarrhea start -- DO NOT wait for signs of dehydration.
Always encourage a person who is sick to drink fluids. Remember that fluid needs are greater with a fever, vomiting, or diarrhea. The easiest signs to monitor are urine output (there should be frequent wet diapers or trips to the bathroom), saliva in the mouth, and tears when crying.
Chen L. Infectious diarrheal diseases and dehydration. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosenâ€™s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier; 2009:chap 171.
Greenbaum LA. Deficit therapy. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 10th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 54.