Introduction

We all feel thirsty at various times of the day. Drinking water is essential to maintaining normal body temperature and removing waste. 

However, if you feel thirsty during most part of the day and it continues even after you drink water, this can be a sign that something is wrong in your body.

This feeling of excessive thirst is called polydipsia. Polydipsia occurs due to some underlying health conditions such as diabetes mellitus and diabetes insipidus.

What is polydipsia?

Polydipsia is a condition characterised by excessive thirst. People with this condition feel a constant urge to drink fluids, which occurs due to fluid loss from the body. 

Polydipsia is often accompanied by dry mouth or xerostomia and a frequent urge to pee.¹ The condition may last from weeks to months until the underlying health problem is addressed.

What is the cause of polydipsia?

The feeling of excessive thirst may be due to the following reasons:

• Diabetes mellitus

Polydipsia is one of the main signs of diabetes mellitus. High blood sugar level is a characteristic feature of diabetes mellitus. Your kidneys produce more urine in order to remove the excess glucose from the body. This causes you to feel thirsty more often.² 

• Diabetes insipidus

Diabetes insipidus is a condition that occurs either due to insufficient production of antidiuretic hormone by the kidneys(central diabetes insipidus) or due to inadequate response of kidneys to this hormone(nephrogenic diabetic insipidus). 

Antidiuretic hormone(ADH) helps to reduce water loss through the kidneys by making the urine more concentrated. 

ADH deficiency causes increased water loss through urine. This produces excessive thirst or polydipsia.

• Primary polydipsia

It is a type of polydipsia where excessive thirst causes polyuria with highly diluted urine and hyponatremia(low blood sodium). Primary polydipsia can be of 2 types, psychogenic and dipsogenic.

Psychogenic polydipsia occurs in patients having psychiatric problems. Whereas, in Dipsogenic polydipsia, the patient knowingly drinks lots of water. It is also called compulsive water drinking.

• Sepsis and burns

Certain conditions like sepsis, burns, as well as heart, kidney, and liver failure lead to fluid loss. This causes polydipsia.

• Dehydration

• Cystic disease

The development of Cysts in and around your kidneys can cause polydipsia.

• Hypokalemia

Reduced potassium levels in your body also cause polydipsia.

• Psychogenic cause

Certain mental health disorders like anxiety and schizophrenia can also cause polydipsia.¹

• Pregnancy

Feeling thirsty and urinating frequently during pregnancy is a common sign of pregnancy. This is a sign of gestational diabetes.²

• Hypercalcemia

Polydipsia is one of the symptoms of hypercalcemia.⁴

• Medications

Certain medications like antidiuretics, antipsychotics, and antidepressants cause excessive thirst.³ 

Signs and symptoms of polydipsia

When you have polydipsia, you feel excessively thirsty. There is an abnormal urge to drink water even after you have taken plenty of fluids. 

Signs and symptoms include:⁸

• Excessive thirst
• Increased urine output up to 12 liters of urine per day
• Clear and dilute urine
• Dry mouth
• Fatigue
• Dizziness
• Tremors
• Nausea or vomiting
• Confusion

Diagnosis of polydipsia

Proper diagnosis of the underlying condition is essential to manage polydipsia. Diagnosis of polydipsia involves:⁵

• Water deprivation test

Diabetes insipidus is diagnosed using the water deprivation test. The patient is retained from drinking fluids for a few hours. The healthcare provider then measures your body weight, amount of urine produced, concentration of your urine and blood, and amount of ADH in your blood. ADH is administered to check if your kidneys produce enough ADH and if they respond to it properly. 

• Urine test

Urine is tested to determine if there is too much water or glucose in it. This is used to diagnose diabetes insipidus and diabetes mellitus respectively. Urine is tested for:⁶

• serum electrolytes
• glucose
• urine specific gravity
• plasma and urinary osmolality 
• ADH level

• Blood tests

Blood is tested to determine the levels of sodium, potassium and calcium. This is useful for diagnosing diabetes mellitus. Complete blood count and blood glucose levels are also tested.

• MRI

MRI scan checks for problems related to the hypothalamus and pituitary. 

• Family history 

If family members have diabetes mellitus or diabetes insipidus, there is a probability that you have the same condition that accounts for polydipsia.

Treatment of polydipsia

In cases of mild polydipsia, drink more water and avoid getting dehydrated. Other cases of polydipsia are treated based on the cause.⁵

• Central diabetes insipidus 

Central diabetes insipidus occurs due to tumour or other disorders of the pituitary gland or the hypothalamus. This causes insufficient production of antidiuretic hormone by the kidneys. The underlying disorder is initially treated in central diabetes insipidus.

Further treatment involves the administration of a manufactured hormone called Desmopressin. It reduces the amount of urine produced by the body by replacing antidiuretic hormone. 

• Nephrogenic diabetic insipidus 

In this type, your kidneys do not respond to antidiuretic hormone. Hence, taking Desmopressin will not help.

A low-salt diet is advised to reduce the amount of urine produced by the kidneys. A drug named hydrochlorothiazide is used to relieve the symptoms.

• Primary polydipsia

The ideal treatment for primary polydipsia is to reduce the intake of water. However, this fails in patients with excessive thirst and compulsive drinking behaviour.⁷

Management involves following a balanced diet and avoiding drugs that cause dry mouth. This along with counseling can make you aware of your water consumption.

• Diabetes mellitus

If polydipsia is due to diabetes mellitus, your blood sugar levels need to be managed to relieve the symptoms.

• Gestational diabetes insipidus 

Desmopressin hormone is used for the management of gestational diabetes insipidus.

• Drugs

Drugs such as anticholinergics cause dry mouth. Your healthcare provider will adjust the dose of your medication or change your prescription as required.

FAQs

What drugs can cause polydipsia?

Medications such as anticholinergics, antipsychotics, anticonvulsants, and antidepressants cause polydipsia.

What causes polydipsia?

Polydipsia can occur due to underlying conditions such as diabetes mellitus, diabetes insipidus, burns, sepsis, kidney failure, dehydration, hypokalemia, cystic disease and psychiatric disorders. It may also be a side effect of taking certain drugs.

Can polydipsia be cured?

Polydipsia is managed by treating the underlying medical conditions. This includes management of blood sugar levels, taking medications such as desmopressin, counselling in case of psychological causes, and changes in your lifestyle.

Summary

Polydipsia is a condition of having excessive thirst. Being thirsty sometimes is usually normal. But, if you are feeling thirsty all the time, you might have to consult your doctor. Polydipsia occurs due to some underlying medical conditions such as diabetes mellitus, diabetes insipidus, hypokalemia, kidney failure, burns, sepsis, and psychiatric disorders. It may also be a side effect of taking certain drugs. Consult a healthcare professional to find out the cause of polydipsia and determine the treatment required.