Dehydration and Diabetes

Dehydration and Diabetes


Dehydration is an excessive loss of water from the body. In diabetes patients, high glucose (blood sugar) can cause or contribute to dehydration. It can also occur when body fluid is lost through frequent urination, sweating, diarrhea or vomiting.

Loss of fluid can cause a variety of problems for patients because water is critical to survival, in that it:

  • Forms the basis for all body fluids, including the blood and digestive juices
  • Aids in the transportation and absorption of nutrients
  • Helps eliminate wastes

The major symptom of dehydration is thirst, but fatigue can set in even with mild dehydration. More severe forms of dehydration can lead to shock and become life-threatening. With diabetes, dehydration can be involved in serious conditions including ketoacidosis and coma.

About dehydration

Dehydration occurs when the body loses so much fluid that it no longer functions at optimal levels. People with diabetes are at risk for dehydration because high glucose (blood sugar) levels in the bloodstream trigger dehydration. This occurs because the kidneys cannot absorb excess glucose and must expel it by forming increasing amounts of urine, which deprives the body of fluids.

Other causes of dehydration include:

  • Fluid loss as a result of vomiting, diarrhea, excessive urination (polyuria) or sweating
  • Inadequate fluid intake
  • A combination of fluid loss and insufficient fluid intake

Dehydration can be classified as mild, moderate or severe. The determination is based on the percentage of body weight lost during an acute illness. This includes:

  • Mild dehydration. A loss of 3 to 5 percent of body weight.
  • Moderate dehydration. A loss of 6 to 9 percent of body weight.
  • Severe dehydration. A loss of more than 10 percent of body weight. Severe dehydration is a life-threatening condition that demands immediate medical attention.

Dehydration is particularly dangerous in young children, who have a high body surface area relative to body size and weight. For this reason, children lose a lot of fluid through the skin as they perspire. Children are at additional risk of dehydration because they:

  • Have high metabolisms that quickly turn over the water and electrolytes (substances within water important for good health) they consume, further contributing to the risk of dehydration.
  • Have kidneys that are not as efficient at conserving water as those of adults.
  • Have immune systems that are more vulnerable than an adult’s. This increases the risk of contracting illnesses that cause symptoms (such as vomiting and diarrhea) that promote dehydration.
  • Do not always drink enough water when they are ill.
  • Depend on caregivers to provide them with food and fluids.

Children who experience a surge in glucose levels can become dehydrated quickly. In infants, dehydration can set in within several hours.

Older adults are also at high risk of dehydration because they may have:

  • Decreased thirst sensation, which sometimes keeps them from drinking as much as they should
  • Kidneys that do not work efficiently
  • Physical problems such as arthritis that may make it difficult for them to drink
  • Medications that increase the risk of dehydration
  • Problems such as incontinence or physical incapacitation that may cause them to intentionally limit fluid intake to decrease trips to the bathroom
  • Impairments in memory or other cognitive functions that can cause them to forget to drink enough water

Two conditions that can affect diabetic individuals when glucose levels rise – diabetic ketoacidosis and hyperosmolar hyperglycemic nonketotic syndrome (HHNS, also called nonketotic hyperosmolar state) – can also involve or trigger dehydration.

Dehydration can also play a role in other disorders, including kidney stones and gout, both of which are more prevalent in diabetes patients than in nondiabetics.

The dehydration associated withtype 1 diabetes,type 2 diabetesand other forms of diabetes mellitus should not be confused with an unrelated endocrine condition calleddiabetes insipidus. This is a rare condition in which the kidneys are unable to conserve water. This leads to increased urination and excessive thirst. 

Though it is important to drink enough water and avoid dehydration, consumption of too much fluid can also cause health problems. Overhydration, where the body loses less water than it takes in, causes insufficient levels of sodium in the blood (hyponatremia). Extreme cases of overhydration, or water intoxication (regularly drinking more than 2 gallons or 7.6 liters a day), can cause tissue damage, confusion, seizures, coma and even death.

Dozens of studies indicate that, generally, men need an average of 125 ounces (3.7 liters) and women 91 ounces (2.7 liters) a day, according to the Institute of Medicine, which advises moderating consumption of sodium rather than overhydrating. Individuals who are very active physically or live in hot climates may need to drink more.

Potential causes of dehydration

Dehydration occurs when the body loses large amounts of fluids, causing the body to reabsorb fluid from the blood and other body tissues. It is natural for the body to lose more than 10 cups (2.5 liters) of water every day simply through basic life processes such as perspiration, breathing and elimination of wastes. The body also loses electrolytes (including potassium, sodium and calcium) that maintain the balance of fluids in the body.

Normally, a person is able to replace the fluids lost through eating and drinking. However, in some cases more water and salt is lost than is replaced. This causes the body to dry out, or dehydrate. On average, water makes up 60 percent a person’s body weight. Thus, dehydration can seriously affect health.

Several factors and conditions can exacerbate the loss of fluid that leads to dehydration. These include:

  • High glucose (blood sugar) levels. Excess glucose in the bloodstream causes the body to become dehydrated. For this reason, people with diabetes are at a high risk for dehydration.
  • Fluid loss. Sources of fluid loss include excessive urine output (polyuria). This symptom is commonly associated with diabetes. It also includes vomiting, diarrhea, excessive perspiration and fever.
  • Inadequate intake of fluids. Failure to drink enough fluids is often the result of feeling unwell because of illnesses and conditions such as nausea, mouth sores, sore throat or loss of appetite.
  • Illnesses. A wide range of conditions ranging from the flu to food poisoning can cause dehydration, especially if diarrhea or vomiting is involved.
  • Medications. Diuretics are perhaps the best-known of the drugs that can cause dehydration. The diabetes drug metformin, a biguanide, is also of concern, according to the American Diabetes Association. Supplements such as creatine can also cause dehydration.
  • Diet. Sodium, caffeine and alcohol can lead to dehydration. Researchers have found that dehydration can be a side effect of low-carbohydrate diets.
  • Environment. Airline travel and other dry environments can encourage dehydration.

Signs and symptoms of dehydration

Diabetes patients should be alert for the symptoms of dehydration, because it often can be easily and successfully treated in its earliest stages. Symptoms of dehydration include:

  • Thirst
  • Little or no urine
  • Concentrated, dark urine
  • Sunken eyes
  • Dry lips, mouth and tongue
  • Inability to keep fluids down
  • Lack of skin elasticity known as poor skin turgor
  • Decreased tears
  • Deep, rapid breathing
  • Lethargic or comatose state (associated with severe dehydration)

Severe dehydration is a life-threatening condition that requires immediate medical attention. When not treated, the lack of fluid prevents blood from getting to the vital organs, which may lead to shock. Symptoms of severe dehydration include:

  • Altered mental status
  • Dark amber or brown urine
  • Weak and rapid pulse
  • Skin that is either cold and clammy or hot and dry
  • Sunken fontanels (the soft spot on top of a baby’s head) in infants
  • Extreme thirst (polydipsia)
  • Loss of consciousness

Once a person becomes dehydrated, physiological changes occur that can affect the person’s health. These include:

  • The heart pumps harder to maintain adequate blood flow to the organs.
  • The body is less able to control blood pressure.
  • Distribution of nutrients and elimination of wastes are impaired.
  • Reduced blood flow to the skin and lower amounts of water in the system keep the body from perspiring and dissipating heat. This can lead to heat exhaustion or potentially life-threatening heat stroke.

Prolonged or severe dehydration can lead to a number of life-threatening complications. These include:

  • Brain swelling (cerebral edema)
  • Seizures
  • Kidney failure
  • Coma and death

Diagnosis methods for dehydration

A physician is likely to take a medical history and conduct a physical examination before making a diagnosis. In diagnosing dehydration, a physician will look for:

  • Low blood pressure (hypotension)
  • Dryness of mouth and lips
  • Rapid heart rate (tachycardia)
  • Delayed refilling of the capillaries
  • Shock

Blood tests and urine tests may help confirm a diagnosis of dehydration. Tests that are often used to diagnose dehydration include:

  • Blood chemistries. These can check levels of electrolytes (particularly sodium and potassium) and bicarbonate.
  • Urine specific gravity. This measures the specific gravity of urine, a reflection of the concentration of particles in urine. A high specific gravity indicates substantial dehydration.
  • Blood urea nitrogen (BUN) test. This waste product test measures the amount of a byproduct of protein metabolism.
  • Creatinine test. Elevated readings of the muscle constituent creatine may indicate dehydration.
  • Complete blood count (CBC). Signs of concentrated blood (hemoconcentration) indicate dehydration. 

Treatment options for dehydration

When patients recognize dehydration in the early to moderate stages, it can be treated with home remedies. Basic steps to treat the condition differ by age and include:

Infants through 1 year of age:

  • Nurse or bottle-feed an infant at more frequent intervals to replace fluids.
  • Use an oral rehydration solution (containing water and salts in proportions designed to restore fluids and electrolytes) and administer via dropper, spoon or bottle.
  • Replace lost fluids with cereal. Rice cereal, strained bananas and mashed potatoes can be used in children who have previously eaten these foods.

Children, ages 1 to 11:

  • Replace fluids with oral rehydration solution, half-strength orange juice or water. Allow children to drink as much as they want.
  • Encourage children (ages 4 to 10) to drink at least six to 10 glasses of liquids to replace lost fluid.
  • Fluid-replacement alternatives include popsicles and cereal with milk.

Adults and children older than age 12:

  • Consume a rehydration drink, water or juice to replace fluids and minerals.  Patients who need to limit their intake of sugar are advised to ask their physician which beverages are appropriate for them. Drink 2 quarts (1.9 liters) of cool liquids over a period of two to four hours. Adults are often advised to drink at least eight glasses of noncaffeinated liquids each day to replace fluids that are lost.
  • People who become dehydrated during strenuous activity should stop the activity and rest for 24 hours while continuing fluid replacement. People often feel better within a few hours, but total rehydration can take 36 hours.

See a physician if the following symptoms appear despite home treatments:

  • Decreased alertness
  • Dizziness, lightheadedness or fainting when rising from lying to sitting, or sitting to standing (orthostatic hypotension, a condition involving low blood pressure)
  • Decreased urination
  • Other symptoms related to dehydration, including increased frequency or severity of any symptoms

Patients – particularly young children and older adults – should contact a physician if the following symptoms are experienced:

  • Severe diarrhea, or moderate diarrhea for more than five days
  • Vomiting for 12 hours or longer
  • Inability to keep down fluids
  • Irritability, sleepiness or fatigue

Prevention methods for dehydration

People with diabetes are at high risk for dehydration and certain steps can be taken that will drastically reduce the odds of losing excess amounts of fluid.

Rising glucose (blood sugar) is the major trigger for dehydration in diabetic individuals. Once a person becomes dehydrated, glucose levels will rise even higher. Maintaining strict control of glucose levels is the best way to keep this cycle of dehydration from occurring.

In addition to controlling glucose levels, patients can also reduce the risk of dehydration by drinking plenty of fluids. Recommendations vary. To help prevent dehydration, people should drink at least eight 8-ounce glasses (or 1.9 liters total) of water and other noncaffeinated liquids each day, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The Institute of Medicine suggests that most men need 125 ounces (3.7 liters) and women 91 ounces (2.7 liters) a day. Individuals are advised to consult their physician about the right amount for them.

Patients who have trouble remembering to drink regularly through the day should try techniques that will help them remember. For instance, patients can buy water bottles and place them in conspicuous locations wherever they spend a lot of time during the day, such as at home, a workplace, car or school. 

Diabetic patients should be extra careful to consume water during bouts of strenuous activity such as exercise, or when outside on hot days. Water should be consumed even when the person does not feel thirsty.

Children are particularly susceptible to diabetic dehydration, mostly because their large amount of skin relative to body size and weight causes them to lose a lot of fluid through perspiration. Sicknesses such as a cold or the flu can further raise the risk of dehydration in children. This is why it is especially important for children to drink plenty of fluids during illness.

Oral rehydration solutions such as Pedialyte or Ricelyte are particularly helpful. These contain water and salts in proportions designed to restore fluids and electrolytes. Children should consume an ounce every 20 minutes. If the child has difficulty drinking, Popsicles can be a good alternative.

In addition to beverages, several foods also have high water content. These include:

  • Vegetables such as lettuce, celery, broccoli and carrots
  • Fruits such as watermelons, apples, grapefruits and orange juice
  • Milk and yogurt
  • Soups (low sodium)

Questions for your doctor about dehydration

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about dehydration:

  1. How do my diabetes and glucose control affect my risk of dehydration?
  2. How can dehydration affect my diabetes?
  3. Am I at risk of complications such as ketoacidosis, hyperosmolar hyperglycemic nonketotic syndrome or diabetic coma?
  4. What treatment plan should I have in place in case of such emergencies?
  5. What can happen if I drink too much water?
  6. Am I at risk of overhydration?
  7. How much water should I generally drink?
  8. In what circumstances should I drink more or less?
  9. What signs of dehydration should I watch for?
  10. How can I distinguish mild dehydration that I can treat myself from serious dehydration that needs medical attention?
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