Hypertonic Dehydration: What You Need to Know

Hypertonic Dehydration: What You Need to Know

What Is Hypertonic Dehydration?

The term “hyper” means too much or excessive. So, hypertonic dehydration refers to excess water loss from your body. If you are dehydrated, then you have lost too much fluid due to vomiting, diarrhea, sweating and other symptoms.

Hypertonic dehydration is not the same thing as hyponatremia (low sodium level). Hyponatremia occurs when there is too little salt in your blood. When you drink too much water, it dilutes the amount of salt in your blood so that it becomes less concentrated. That’s why drinking lots of fluids may cause you to feel thirsty. However, if you lose too much water through sweat, vomiting or diarrhea, then you could develop hyponatremia.

How Does Hypertonic Dehydration Affect Your Body?

If you suffer from hypertonic dehydration, your body loses more than just water. The loss of electrolytes causes problems with your heart and brain. In severe cases, it can also lead to death. There are two types of hypertonic dehydration, namely:

Isotonic Dehydration – Your body contains the same amount of water and salt. Symptoms include decreased blood pressure and a faster heart rate.

Hypertonic Dehydration – A higher concentration of salt than water. This can cause low blood pressure and a slower heart rate.

What Are the Causes of Hypertonic Dehydration?

There are a number of conditions that can lead to hypertonic dehydration. These include:

Vomiting or diarrhea

Prolonged exercise or exposure to the sun (especially in hot, humid weather)

Burns from fire or chemicals

Allergic reaction or other health condition

What Are the Risk Factors for Developing It?

Most people who develop hypertonic dehydration are either children or elderly adults. That’s because both groups lose more water and other essential nutrients through urine, stools, skin and breathing. Other risk factors include:


Liver disease

Kidney disease

Bone marrow problems

Anemia or other condition that causes the blood to have too few red blood cells

How Is It Diagnosed?

If you think you might have hypertonic dehydration, then you should see a doctor right away. The following tests and exams can be used to diagnose it:

Physical exam

Blood tests to measure the amount of water, sodium and other chemicals in your blood


Chest x-ray

Electrocardiogram (ECG or EKG)

What Are the Types of Hypertonic Dehydration?

There are two types of hypertonic dehydration: isotonic and hypertonic. Isotonic dehydration is the most common.

Isotonic Dehydration

Isotonic dehydration means that there is an equal amount of water and salt in your body. It’s often caused by prolonged diarrhea, vomiting or excessive sweating. This type of dehydration can also be caused by diabetes, Addison’s disease or other conditions that affect the body’s ability to regulate sodium.

Hypertonic Dehydration

Hypertonic dehydration means that there is a higher amount of salt than water in your body. It can be caused by conditions such as excessive vomiting or taking diuretics. Other causes include burns, exposure to chemicals or severe diarrhea due to an infection such as cholera.

What Can You Do to Prevent It?

You can take the following steps to prevent hypertonic dehydration:

Drink plenty of liquids, especially water.

Eat foods that contain a high amount of electrolytes, such as bananas.

Be sure to urinate and sweat as you lose fluids. This will help to keep from getting dehydrated.

How Is It Treated?

Treating hypertonic dehydration will depend on the cause and how severe it is. The most common treatment is intravenous (IV) fluids. This can help replenish the water and electrolytes that you’ve lost. You may also be given medicines to treat any underlying conditions. Surgery may be required in some cases.

If you experience symptoms of isotonic dehydration, then you can treat them at home. This includes drinking plenty of fluids and taking electrolyte replacement drinks. You can also replenish your body’s water by drinking coconut water.


The outlook is good if you’re treated promptly for hypertonic dehydration. This is especially true if the cause of your dehydration can be identified and treated as well.

Adults and children with diarrhea should continue to drink fluids until the diarrhea slows or stops. If untreated, severe diarrhea and vomiting can lead to a serious loss of vital minerals and vitamins. This is a medical emergency that may result in death even if hypertonic dehydration is treated.

It’s important to monitor children with diarrhea to make sure that they’re able to keep fluids down. If your child is unable to keep liquids down for more than 2 hours, seek medical help immediately.

Sources & references used in this article:

High prevalence of plasma hypertonicity among community-dwelling older adults: results from NHANES III by JD Stookey – Journal of the American Dietetic Association, 2005 – Elsevier

Hypertonic Dehydration in Infants. The Clinical and Biochemical Features. by D Slone, SE Levin, I Orska – Medical Proceedings, 1958 – cabdirect.org

Hypertonic challenge to porcine vocal folds: effects on epithelial barrier function by M Sivasankar, E Erickson… – … –Head and Neck …, 2010 – journals.sagepub.com

Hypertonic dehydration (hypernatremia): the role of feedings high in solutes. by E Colle, E Ayoub, R Raile – Pediatrics, 1958 – cabdirect.org

Water-loss dehydration and aging by L Hooper, D Bunn, FO Jimoh… – Mechanisms of Ageing …, 2014 – Elsevier

Learning (by) osmosis: an approach to teaching osmolarity and tonicity by P Vujovic, M Chirillo… – Advances in physiology …, 2018 – journals.physiology.org

The role of hypertonic saline dextran in trauma resuscitation by AM Perera, KM Porter – Trauma, 2002 – journals.sagepub.com