It is not a disease by itself but can be an important symptom of certain health problems, such as diabetes. People who have this symptom should always see a doctor.
This article aims to help readers understand polydipsia and how to manage it.
What is polydipsia?
If a person is thirsty all of the time then polydipsia may be the cause.
Everyone knows the feeling of thirst. For example, a person may drink large amounts of fluid to relieve thirst brought on after eating salty food, strenuous exercise, or a day in the hot sun.
This type of thirst usually doesn't last long and is easily quenched with fluids.
Polydipsia, on the other hand, can last days, weeks, or even longer depending on the cause. An individual with polydipsia tends to be thirsty most if not all the time, despite regularly drinking large amounts of fluid.
Comments such as "I can't get enough to drink" or "my mouth is so dry" are possible indicators that the person has polydipsia.
Polyuria (large amounts of urine) almost always accompanies polydipsia. One of the kidneys' primary jobs is to help the body find the right balance of water and other fluids.
Polyuria is defined as passing 3 or more liters of urine in 24 hours in adults.
The kidneys also pass more than fluid. For example, sodium and potassium often leave the body along with urine. This can lead to changes in these salts in the body, which can introduce other problems.
While other symptoms found with polydipsia depend on its cause, a common symptom is a dry mouth.
How much water should I drink every day?
How much water a person needs depends on how healthy they are, how much they exercise, and where they live. There is not one set amount of water that fits everyone.
People can determine how much fluid they drink by starting the day with a measured container of water and then drinking only that water, noting the amount used in 24 hours. People should refill the container through the day as needed.
Remember that fluid is more than just water. When measuring amounts for polydipsia, people should include all liquids, such as fruit juice and coffee.
People asked to measure their urine are usually given a special container for collection.
Some causes of polydipsia include:
Polydipsia is a common sign of either early or uncontrolled diabetes mellitus.
Insulin helps glucose enter the cells where it is used for energy. With this form of diabetes, high levels of glucose in the blood pull water out of the cells. The kidneys then pass more urine, causing dehydration and thirst.
Common diabetes mellitus symptoms include:
Extreme hunger is another possible symptom of diabetes mellitus.
- extreme and uncontrolled hunger
- blurred vision
- extreme fatigue or lack of energy
- genital itching
- slow healing of wounds or cuts
- weight change (gain or loss)
- frequent or returning infections
- tingling or numbness in the hands or feet
Diabetes insipidus is a rare condition unrelated to diabetes mellitus. Instead, it relates to a hormone called vasopressin, an antidiuretic hormone that helps control fluid removal through the kidneys.
Diabetes insipidus is caused by low levels of vasopressin, or when the kidneys don't respond properly to this hormone. A person with diabetes insipidus often passes large amounts of clear, odorless urine.
A person with uncorrected diabetes insipidus usually becomes very thirsty, developing polydipsia. Rarely, severe dehydration may also occur.
Dehydration symptoms include:
- dry skin or eyes
People with any of the last three symptoms should seek immediate care, even if they do not think they are dehydrated.
Psychogenic polydipsia is a condition that tends to be diagnosed when a person compulsively feels the need to drink as if dehydrated, even if they are not. They also do not seem to have any other condition to explain their thirst.
Psychogenic polydipsia may occur in certain psychiatric conditions. Those identified to date include schizophrenia, bipolar disease, and depression. Other mental health disorders may have the same symptoms. Many of the medications given for these conditions also increase thirst.
Two terms used to describe this situation are "compulsive water drinking" and "self-induced water intoxication." While the word "water" is used, a person may seek almost any fluid.
When to see a doctor
A urine sample may be ordered by a healthcare professional to determine if the symptoms are due to diabetes mellitus.
Anyone with polydipsia should see a doctor for a diagnosis.
People who already have diabetes mellitus may want to check their blood sugar levels before seeing their doctor. If the levels are high, and a person is experiencing polyuria and extreme hunger, uncontrolled diabetes mellitus is the most likely cause.
This information should still be given to the doctor, along with a history of fluid intake if possible. Doctors will likely order blood and urine tests to check blood sugar levels and help identify whether the symptoms are due to diabetes mellitus.
A common blood test called HbA1c measures a person's sugar levels over the previous 3 months and can be used when diabetes mellitus is first diagnosed.
For pregnant women, a doctor may also order an oral glucose tolerance test.
Doctors may order other tests when diabetes mellitus is not the cause, or not the only cause, of an individual's symptoms. These tests include:
- checking vasopressin levels
- checking sodium and potassium levels in the blood
- a fluid deprivation test
Some drugs may cause or add to polydipsia and polyuria. For this reason, people should take all of their medications with them when they visit the doctor.
A diagnosis of psychogenic polydipsia can be difficult. Caregivers, family, and friends need to watch for all fluids a person drinks. Fluids may be more than water and include drinks, such as juice and coffee.
If a doctor suspects that a person may have psychogenic polydipsia, they may test for low sodium levels in the blood, which may or may not accompany this cause of polydipsia.
Treatment of polydipsia depends on the underlying cause.
For diabetes mellitus, the goal is to bring high blood sugar levels back down. The best way to stabilize sugar levels is to following the doctor's advice regarding exercise, meal plans, and medication.
Diabetes insipidus is often managed by simply drinking the amount of water advised by the doctor. This is meant to help treat or prevent dehydration. In some cases, a doctor will prescribe a medication called desmopressin, a man-made form of vasopressin.
People with psychogenic polydipsia may require counseling to help them overcome their compulsion to drink large, but unneeded, amounts of fluid.
Early recognition and treatment of polydipsia is key to preventing possible problems.
In most cases, polydipsia is easily managed and unlikely to return once its cause is corrected.