Dehydration

Definition

Dehydration occurs when your body does not have as much water and fluids as it needs.

Dehydration can be mild, moderate, or severe, based on how much of your body's fluid is lost or not replaced. Severe dehydration is a life-threatening emergency.

Alternative Names

Vomiting - dehydration; Diarrhea - dehydration; Diabetes - dehydration; Stomach flu - dehydration; Gastroenteritis - dehydration; Excessive sweating - dehydration

Causes

You can become dehydrated if you lose too much fluid, do not drink enough water or fluids, or both.

Your body may lose a lot of fluid from:

You might not drink enough fluids because:

Older adults and people with certain diseases, such as diabetes, are also at higher risk for dehydration.

Symptoms

Signs of mild to moderate dehydration include:

Signs of severe dehydration include:

Exams and Tests

Your health care provider will look for these signs of dehydration:

Your provider may do lab tests such as:

Treatment

To treat dehydration:

For more severe dehydration or heat emergency, you may need to stay in a hospital and receive fluid through a vein (IV). The provider will also treat the cause of the dehydration.

Dehydration caused by a stomach or intestinal virus should get better on its own after a few days.

Outlook (Prognosis)

If you notice signs of dehydration and treat it quickly, you should recover completely.

Possible Complications

Untreated severe dehydration may cause:

When to Contact a Medical Professional

You should call 911 or the local emergency number if:

Prevention

To prevent dehydration:

References

Kenefick RW, Cheuvront SN, Leon LR, O'Brien KK. Dehydration and rehydration. In: Auerbach PS, Cushing TA, Harris NS, eds. Auerbach's Wilderness Medicine. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 89.

Padlipsky P, White W. Pediatric infectious diarrheal disease and dehydration. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 167.



Review Date: 8/5/2023
Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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