Also called: Excessive Thirst, Extreme Thirst


Polydipsia is the medical term for excessive thirst. This increased thirst often leads to a person drinking too much water.

Drinking enough water is a healthy habit. Consuming too much, however, can be harmful and may be a sign of disease. For example, increased thirst is one of several common signs of diabetes or prediabetes. Polydipsia may provide an important clue for the millions of Americans who are diabetic but have yet to be diagnosed. Severe polydipsia may indicate serious diabetic complications such as diabetic ketoacidosis.

Polydipsia can also be due to many other conditions. These include diabetes insipidus, other endocrine disorders, dehydration, kidney disease, liver disease, urinary tract infection, mineral imbalances, head injury, drug abuse, emotional disorders and Wolfram syndrome. Certain medications can also cause excessive thirst.

Anyone experiencing persistent or unexplained thirst should discuss the matter with a physician, especially if this symptom appears with other signs of disease. For example, someone experiencing unexplained polydipsia combined with polyphagia (excessive hunger) should contact a healthcare provider.

About polydipsia

Polydipsia is an excessive and sometimes constant thirst, usually leading to an increased consumption of water. The increased intake of water can be the result of many factors, including:

  • Exertion
  • Injury
  • Illness
  • Diet
  • A side effect of medication

However, when increased thirst cannot be explained by lifestyle changes or temporary illness, a physician should be contacted as it may be a sign of a number of diseases and disorders, including diabetes and prediabetes. About 20.8 million Americans, 6.2 million of them undiagnosed, have diabetes, and 41 million have prediabetes, according to the U.S. Centers for Disease Control and Prevention (CDC).

Definitions of polydipsia vary. Excess intake of fluids in adults can be defined as the consumption of more than a gallon (128 ounces or 3.8 liters) of beverages a day, according to the Diabetes Insipidus Foundation.

Recommendations that people should drink a lot of water to avoid dehydration are leading some to become overhydrated, according to the Institute of Medicine. 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 consuming less sodium rather than overhydrating. Individuals who are very active physically or live in hot climates may need to drink more.

Because polydipsia often leads to excessive consumption of water, it is closely linked with polyuria (the production of large volumes of urine). Experiencing excessive thirst and possibly excessive urination does not usually constitute a medical emergency, but several potentially serious diseases may be the cause behind these symptoms.

In addition to polydipsia, polyuria and dehydration, several other symptoms can suggest diabetes. These include polyphagia, unexplained weight loss, fatigue, dizziness and fainting.

Potential causes of polydipsia

There are many reasons for excessive thirst. Polydipsia is a common symptom for many normal activities, including:

  • Exercise
  • Loss of fluids, possibly by excessive sweating
  • Consuming spicy or salty foods, alcohol or caffeine

Certain medications can also result in the body craving more fluids, including:

  • Diuretics. Medications that stimulate the creation and release of urine in an effort to reduce the amount of body fluid. Diuretics are often prescribed to treat conditions such as high blood pressure, heart failure or edema. However, diuretics can raise glucose (blood sugar) levels, so close monitoring of glucose is important for people who have diabetes mellitus. Diuretics are also prescribed for some patients diagnosed with diabetes insipidus.
  • Anticholinergics. Medications that open bronchial tubes to improve breathing and help clear mucus from the airways. They are primarily used in the treatment of asthma or other breathing problems. Some forms of this medication also work as antispasmodics, relieving cramps or stomach spasms. They may be recommended for the treatment of gastrointestinal problems or the prevention of nausea and motion sickness.
  • Antiarrhythmics. Medications to correct abnormal heartbeats.
  • Chemotherapy drugs. Medications used to treat cancer.
  • Many psychiatric medications. Antipsychotics, lithium and tricyclic antidepressants, for example, can dry the mouth.
  • Many gastrointestinal medications. In addition to antispasmotics, GI medications that can dry the mouth include antidiarrheals, antiemetics and proton pump inhibitors.
  • Demeclocycline. An antibiotic used to treat bacterial infections and low levels of sodium (hyponatremia).

However, polydipsia can also be a sign of a more serious underlying problem. Polydipsia and polyuria are not specific to any one disease, but rather are factors in several conditions, including:

  • Dehydration. A reduced level of water in the body. The many causes of dehydration include sweating, vomiting, diarrhea, fever, hot flashes, sunburn, excessive dieting, anorexia nervosa and blood loss. Any of these can, in turn, lead to increased thirst.
  • Hyperglycemia or prediabetes. Higher-than-normal blood glucose levels. Excessive urination and increased thirst are possible symptoms.
  • Diabetes mellitus (DM or “sugar diabetes”). A disorder of the body’s ability to use blood glucose. Two main symptoms are excessive thirst and urination. This type of diabetes includes type 1 and type 2 diabetes.

    Dangerous conditions involving severe hyperglycemia, including diabetic ketoacidosis and hyperosmolar hyperglycemic nonketotic syndrome, may be marked by extreme polydipsia.
  • Diabetes insipidus (DI or “water diabetes”). An uncommon disorder in which the kidneys cannot conserve water, usually because of damage to the pituitary gland or a part of the brain called the hypothalamus. DI and DM have some symptoms in common but are unrelated conditions. DI causes the body to produce large amounts of diluted urine, which in turn leads to an imbalance in the body’s water level. With the increased depletion of water, excessive thirst is a common symptom of DI.
    • Other endocrine disorders. Any disease or disorder of the endocrine system, which is responsible for reproduction, growth, internal balance of body systems and the production of hormones. Too much or too little of any hormone can cause problems in the body. Frequent and excessive thirst are common symptoms for many of these disorders, including:
    • Overactive adrenal glands (hyperadrenalism or Cushing’s disease). Disease in one or both of the adrenal glands, which are located atop the kidneys, can lead to an overactivity of the adrenal glands. As part of their major role in the endocrine system, the adrenal glands secrete the hormones cortisol and aldosterone. These adrenal disorders often show symptoms of increased thirst and urination, among others.
    • Overactive parathyroid glands (hyperparathyroidism). The parathyroid glands release hormones into the bloodstream that regulate the amount of calcium, phosphorous and magnesium going to the bones and blood. If calcium levels get too high, a host of symptoms, including vomiting and polyuria, can lead to excessive thirst.
  • Wolfram syndrome. A rare genetic disorder that includes diabetes mellitus and diabetes insipidus.
  • Kidney disorders. Any disease or disorder of the kidneys, such as diabetic nephropathy. The kidneys clean the blood and keep blood chemicals balanced. Many kidney conditions can result in an increased level of urination and thus result in polydipsia.
  • Dry mouth (xerostomia). The many conditions that can cause dry mouth include Alzheimer’s disease, burning mouth syndrome, HIV/AIDS, hypothyroidism, Parkinson’s disease, sarcoidosis (disease in which small lumps form in organs), Sjogren’s syndrome (an autoimmune disorder) and smoking.
  • High blood calcium (hypercalcemia). Though calcium is by far the most prevalent mineral in the body, when blood calcium is high, it can be a sign of disease. It also can cause constipation, increased thirst and urination, nausea, vomiting, irritability, kidney failure, psychosis and coma.
  • High blood sodium (hypernatremia) or low blood potassium (hypokalemia). Certain minerals are needed in a person’s diet to maintain health. But when sodium is high or potassium low, the body may desire more water. Mineral imbalances can also be a result of taking certain medications.
  • Liver disease. The liver is involved in many functions including maintaining chemical balance, removing toxins and making bile to aid in digestion. There are numerous diseases and disorders of the liver, many of which can lead to the liver malfunctioning or possibly even shutting down. Some of the more common liver diseases include cirrhosis, hepatitis and disease due to alcohol. Symptoms may include nausea, dry mouth and excessive thirst.
  • Excessive bleeding. Bleeding disorders can result in a decrease in blood volume. This loss of body fluids often results in dehydration, which leads to an intensified thirst. Such disorders may involve:
    • Gastrointestinal bleeding
    • Blood loss from any wound severe enough to cause heavy bleeding (hemorrhage)
    • Heavy menstrual bleeding
  • Severe infections or burns. Severe infections can lead to fever, vomiting and diarrhea. Dehydration or excessive thirst resulting from a burn requires prompt medical attention.
  • Urinary tract infections. An infection that develops along the urinary tract, including the kidneys (nephritis), bladder (cystitis) or the tubes leading between them (the ureters) or out of the body (the urethra). Common symptoms include painful urination and three conditions that can lead to increased thirst: fever, vomiting and sometimes diarrhea.
  • Drug abuse. The use of some illegal drugs, such as ecstasy, has been shown to cause excessive thirst.
  • Head injury. Any trauma to the brain, whether or not there is damage, is considered a head injury. Vomiting, which is a common after-effect of a head injury, can lead to excessive thirst.
  • Psychogenic polydipsia. A psychological disorder that leads to compulsive water drinking. It may occur with schizophrenia or obsessive compulsive disorders.

Diagnosis methods for polydipsia

There are many potential causes of polydipsia. The underlying cause of a patient’s symptoms must be determined before an appropriate treatment, if any, can be started.

A physician will most likely take the patient’s medical history and perform a physical examination, as well as determine a time line and possible pattern for the excessive thirst.

Additional questions may be asked regarding the patient’s history and lifestyle, including:

  • Eating and exercise habits
  • Recent illnesses
  • Recent weight loss or gain

If normal activities or causes can be ruled out, then diagnostic testing may be recommended, including:

  • Urine tests:
    • Urine specific gravity test. Shows how well the kidneys are processing varying amounts of water in the urine.
  • Urine osmolality. Shows the concentration particles of the urine and is a more exact measurement of urine than the specific gravity test.

Blood tests:

  • Blood differential. Shows the number and type of white blood cells in the blood as well as providing valuable information on possible infections, allergies, parasites and more.
  • Serum calcium. Shows the level of calcium in serum (the liquid part of blood without blood cells). This blood test is often used to screen for diseases of the parathyroid gland, kidneys and bone.
  • Blood glucose level. Shows the level of sugar in the blood, an important test to diagnose diabetes mellitus and a vital management tool for people with diabetes.
  • Serum osmolality. Shows the comparison of water to chemical substances dissolved in the blood. Increased serum osmolality (hyperosmolality) is seen in a number of conditions, including diabetes insipidus and diabetes mellitus.

Water deprivation test. Shows the presence of the four major forms of diabetes insipidus (gestagenic, neurogenic, nephrogenic and polydipsic) by testing the body’s ability to concentrate urine when the patient has no water to drink for at least eight hours. Weight and plasma measurements are taken at specified intervals after the patient is allowed to drink as usual.

Treatment and prevention of polydipsia

Any subsequent treatment of polydipsia is determined by the cause of the increased thirst. These possible sources can include type 1 diabetes, type 2 diabetes, dehydration, diabetes insipidus and others (see Potential causes).

Once the cause has been found, the course of treatment can begin. For example, the patient may be advised to take certain medications or discontinue other medications.

In most instances, polydipsia cannot be prevented as the occurrences are directly related to the cause and, in fact, may be early warning signs of disease. In the case of psychogenic polydipsia, psychological counseling may be advised.

Questions for your doctor about polydipsia

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 polydipsia:

  1. What is the definition of polydipsia for me?
  2. Could my polydipsia be due to diabetes or to another condition?
  3. What tests for polydipsia might I have to undergo, and what do they involve?
  4. What do my test results show? What is causing my polydipsia?
  5. Does my polydipsia require treatment?
  6. If so, what are my options, and which do you recommend?
  7. How much water should I generally drink?
  8. In what circumstances should I drink more or less?
  9. What can happen if I drink too much or too little?
  10. In addition to polydipsia, what other signs of diabetes should I watch for?
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