Health Library

Dehydration

Definition

Dehydration is when a person loses more fluid than they take in. Losing too much fluid makes it hard or even impossible for your body to work as it should. Drinking fluids can help mild dehydration. Severe dehydration needs immediate medical care.

Causes

To work well, the body needs a certain amount of fluid and things called electrolytes. Water is lost through sweat, urine, bowel movements, and breathing. Drinking and eating helps replace fluids and electrolytes. Dehydration can happen if:

  • Too much fluid is lost
  • Not enough fluids are taken in
  • A mix of both
  • Severe diarrhea and vomiting are the most common causes of dehydration in young children.

    Risk Factors

    Dehydration is more common in young children and older adults. Older adults have less water in their bodies. Health problems or medicine can further reduce the fluids in their bodies.

    Other things that may raise the risk of dehydration are:

    • Vomiting and diarrhea
    • High fever
    • Being in the heat and sun
    • Too much working out or sweating while playing a sport
    • Medicines, including diuretics and laxatives
    • Urinating more often
    • Taking in less fluids due to movement problems, mental health or memory problems, or decreased ability to sense thirst
    • Fluid loss caused by certain health issues such as diabetes, kidney disease, burns , and infection

    Symptoms

    Symptoms vary depending on how bad the dehydration is. A person may have:

    • Dry mouth or feel thirsty
    • Problems making tears, such as when crying
    • Weakness or lightheadedness
    • Not urinating (peeing) as often
    • Concentrated urine—darker color, stronger odor
    • Wrinkled or dry skin or parched, cracked lips
    • Drowsiness
    • Nausea
    • Irritability and confusion
    • Fever
    • Rapid heartbeat or fast breathing
    • Weight loss
    • Signs in infants are a sunken soft spot in the skull or no wet diapers for 3 or more hours
    Soft Spot in Infant Skull
    Infant Soft Spot
    Copyright © Nucleus Medical Media, Inc.

    Dehydration can be very serious and life threatening. A person may need medical care right away.

    Diagnosis

    The doctor will ask about symptoms and health history. A physical exam will be done. Urine and blood tests may be done to look for the cause.

    Treatment

    The goal of treatment is to replace the fluids in the body. The cause of the dehydration will also be treated if it is known.

    Treatment may include:

    Fluid Replacement

    Mild or moderate dehydration can be treated by taking in more fluids. This may be done through:

    • Drinking small amounts of an oral rehydration solution during the day.
    • Drinking plain water or salty liquids like broth for adults.

    Drinks with alcohol and caffeine should be avoided. They can make the fluid loss worse.

    IV fluids will be needed for severe dehydration. It will quickly replace fluids.

    Medicine may be given if vomiting or diarrhea are causing severe fluid loss.

    Prevention

    To help reduce the chances of dehydration:

    • Drink lots of non-caffeinated fluids such as water during the day.
    • Drink in small sips during the day if you are sick.
    • Drink fluids regularly while working out or when outdoors on a hot day. Stop often for fluid breaks.

    Resources

    Family Doctor—American Academy of Family Physicians
    https://www.familydoctor.org

    Healthy Children—American Academy of Pediatrics
    https://www.healthychildren.org

    Canadian Resources

    About Kids Health—The Hospital for Sick Children
    http://www.aboutkidshealth.ca

    Health Canada
    https://www.canada.ca

    References

    Dehydration and hypovolemia in adults. EBSCO DynaMed website. Available at: http://www.dynamed.com/condition/dehydration-and-hypovolemia-in-adults.

    Dehydration and hypovolemia in infants and children. EBSCO DynaMed website. Available at: http://www.dynamed.com/condition/dehydration-and-hypovolemia-in-infants-and-children.

    Rehydration therapy in children. EBSCO DynaMed website. Available at: http://www.dynamed.com/topics/management/rehydration-therapy-in-children.