Polydipsia - Excessive Thirst

Overview, Causes, & Risk Factors

Excessive thirst is an abnormally strong desire to drink liquids. It can related to an underlying medical condition.

What is going on in the body?

Increased thirst is not considered excessive when it is related to a recent lack of drinking fluids. Also, people who have always had a strong desire to drink a lot of fluids are not considered to have excessive thirst. There are many potential causes for this condition.

What are the causes and risks of the condition?

There are many possible causes for excessive thirst. These include:

increased exercise, which can increase the body's water requirements

dehydration. This occur from any of a number of causes including diarrhea, infection, hot weather, vomiting, or the use of medications called diuretics that eliminate fluid from the body.

hormone imbalances. These may include a high level of thyroid hormone, a condition called hyperthyroidism, or a high level of adrenal hormones, called hyperadrenalism.

hypernatremia, which is a high level of sodium in the body

uncontrolled diabetes. This is a condition that causes an increase in blood sugar levels, triggering excessive thirst.

diabetes insipidus. Diabetes insipidus is a disease that causes people to urinate excessively and results in dehydration.

certain drugs or medications. The use of antihistamines, marijuana, caffeine, or alcohol can cause this condition.

psychogenic polydipsia, which is a psychiatric condition that causes a person to feel thirsty for no apparent reason

damage to an area of the brain called the hypothalamus. This is rare.

Other causes are also possible. Sometimes, no cause can be found.

Symptoms & Signs

What are the signs and symptoms of the condition?

When a person complains of an excessive amount of thirst, the healthcare provider will need to know:

when the problem started

whether the person feels dehydrated or has a dry mouth

whether the thirst is constant or occurs only at certain times

what types of liquids the person drinks each day

how much the person drinks each day

whether the person has increased or decreased the amount of fluids he or she drinks each day

whether the person's weight has changed

how much the person exercises

what other medical conditions the person may have

what medications, drugs, or herbs a person may be taking

whether the person is having any other symptoms

Diagnosis & Tests

How is the condition diagnosed?

The healthcare provider will take a medical history and perform a physical exam. This may be all that is needed to determine the cause. In other cases, further testing is needed.

The tests used depend on the suspected cause. Blood tests are commonly done. For example, a blood glucose level can be used to detect diabetes. A blood test called a chem-7 includes a serum sodium test that can detect hypernatremia. A blood alcohol level test can detect alcohol use. An x-ray test called a cranial CT scan may be done if brain damage is suspected.

Prevention & Expectations

What can be done to prevent the condition?

Prevention is often not possible. Drinking extra fluids before exercising can help prevent cases from this cause. Avoiding substances responsible for excessive thirst can prevent cases due to drug use. Taking medications as prescribed and checking blood sugars regularly can prevent some cases due to diabetes.

What are the long-term effects of the condition?

Long-term effects are related to the cause. Uncontrolled diabetes can cause damage to many bodily organs and even result in death. Cases due to dehydration can usually be treated successfully without long term effects. A person with psychogenic polydipsia can sometimes develop dangerous salt imbalances due to excessive water drinking.

What are the risks to others?

Excessive thirst is not contagious and poses no risks to others. If the cause of excessive thirst is dehydration due to an infection, the infection may be contagious.

Treatment & Monitoring

What are the treatments for the condition?

Treatment is directed at the cause. For example, a person with diabetes may use insulin injections or other medications to control blood sugar levels. Someone who is dehydrated is given fluids. If a person is unable to drink extra fluid, it can be supplied an through an intravenous (IV) tube. This is a special thin tube that is inserted through a person's skin and into a vein, usually in the hand or forearm. This may be necessary if a person if vomiting and cannot hold fluids down. Someone with hyperthyroidism may need medication, surgery, or radioactive therapy to treat the condition. A person who abuses drugs may need drug rehabilitation. An individual who has psychogenic polydipsia is often treated with psychotherapy, and possibly medications.

What are the side effects of the treatments?

Side effects depend on the treatments used. For example, medications can cause allergic reactions, stomach upset or headaches. Surgery carries a risk of bleeding and infection.

What happens after treatment for the condition?

Once treated, a person with dehydration often needs no further treatment. Someone with diabetes needs lifelong monitoring and treatment for their diabetes. An individual who stops abusing drugs may not longer experience excessive thirst.

How is the condition monitored?

Any changes or response to treatment can be reported to the healthcare provider. Other monitoring is related to the cause. For example, someone with diabetes needs to check blood sugar levels every day.