Polyuria (Excessive Urination) Causes & Treatments Explained

What Is Polyuria?

Polyuria is a condition in which you urinate (pee) large amounts of urine. 

Excessive urination volume is defined as urine output of more than 3 liters, which is equivalent to 3,000 milliliters (mL) or cc, in 24 hours.

This can be due to something as simple as drinking too much water and other fluids, especially alcohol or caffeine. However, it can also be a sign of underlying medical conditions that should be properly diagnosed and treated by a healthcare provider.

How Much Urine Per Day is Normal?

The normal urine volume in adults is 800 mL to 2,000 mL in 24 hours (with a fluid intake of around 2 liters per day). Normal urine production by age group per 24 hours is as follows:

• Infants: 750 mL 

• Children under 5 years of age: 1,000 mL 

• Children 5 to 10 years of age: 1,500 mL

• People 10 years of age and older: 2,000 mL

Difference Between Frequent Urination and Polyuria (Excessive Urine Production)

As noted, polyuria is urine output of more than 3 liters per day. It is different from frequent urination, which is the need to pass urine (pee) many times during the day or night but with normal or less-than-normal urine volumes. Both polyuria and frequent urination can result in nocturia, which is waking up more than once during the night to pee.

Note: Polyuria is also different from dysuria, which is pain with urination, a common symptom in people with a urinary tract infection.

Polyuria vs Overactive Bladder

Polyuria is a symptom, whereas overactive bladder is a condition. While overactive bladder can cause urinary problems, polyuria and overactive bladder are not the same. In people with overactive bladder, there is a strong urge to urinate during the day and night. Symptoms of overactive bladder include urinary urgency, frequent urination, nocturia (waking up more than twice at night to urinate), and urinary incontinence (loss of bladder control). In contrast, polyuria is urinating large quantities of urine (urine volume more than 3 liters per day).

Symptoms of Polyuria

The main symptom of polyuria is a large urine volume (peeing a lot). This can be accompanied by other symptoms such as:

• Increased thirst and fluid intake

• Nocturia (getting up more than once at night to urinate)

• Associated general symptoms such as headache and malaise (feeling unwell) due to dehydration

Polyuria can also be accompanied by shortness of breath and rapid weight loss. These symptoms indicate a more serious underlying condition and should be evaluated by a healthcare provider without delay. 

What Causes Polyuria?

Non-Medical Causes of Polyuria

• Excess fluid consumption—this is known as polydipsia—can lead to polyuria 

• Alcohol and caffeine have diuretic effects and can lead to an increase in urine volume 

• Exposure to cold environments can cause polyuria

• High salt diet

Diabetes Mellitus

Diabetes mellitus is the most common cause of polyuria (excessive urine production). In healthy people, when the kidneys filter blood to make urine, they reabsorb the sugar (glucose) present in the blood and return it to the bloodstream. In people with diabetes, the high blood sugar levels make it harder for the kidneys to reabsorb all the sugar. This results in a high glucose concentration in the urine, which draws more water into the urine, thereby causing polyuria (abnormally large urine volume).

Diabetes Insipidus

Diabetes insipidus is a condition that is unrelated to diabetes mellitus. In people with diabetes insipidus, there is a fluid imbalance in the body. This happens because of low levels of a hormone called the antidiuretic hormone (ADH) or vasopressin. The kidneys need ADH to move fluid that has been filtered into the urine back into the bloodstream. 

There are two types of diabetes insipidus—central diabetes insipidus due to problems with the pituitary gland or hypothalamus in the brain and nephrogenic diabetes insipidus due to problems in the kidneys. 

Symptoms of diabetes insipidus include excessive thirst (especially for cold water), excessive volume of urine (up to 10-20 liters per day), diluted urine (pale urine), nocturia (getting up at night at regular intervals to urinate), and high sodium levels (due to dehydration).

Other Causes of Polyuria: Why Am I Peeing a Lot But Not Diabetic?

In addition to diabetes, even though less common, other medical conditions can also cause polyuria (increased urination). Some of the most common causes of polyuria include:

• Cushing’s syndrome: a condition in which there is too much cortisol hormone in the body

• Chronic kidney disease or reduced kidney function. While low urine output (leading to swelling) is a more commonly known fact of kidney disease, reduced kidney function affects the balance of salt and water in the body, leading to polyuria or nocturnal (nighttime) polyuria. 

• Postobstructive diuresis (prolonged polyuria following relief of chronic urinary obstruction)

• Early sign of chronic pyelonephritis

• Fanconi syndrome: a condition that affects a part of the nephron called the proximal tubule, leading to problems with electrolyte reabsorption.

• Sickle cell anemia: an inherited hemoglobin disorder that can cause kidney damage and affect urine concentration and volume

• Hypercalcemia (high blood calcium levels) that lead to changes in the kidneys

• Hyperparathyroidism (overactive parathyroid glands and hypercalcemia, which can lead to polyuria)

• Hypokalemia (low potassium) which stimulates thirst and can cause polyuria

• Psychological causes such as psychogenic polydipsia (compulsive water-drinking) and certain other psychotic illnesses

• Polyuria can be a side effect of certain medications such as diuretics (water pills), lithium, and, very rare, tetracycline antibiotics

Osmotic Diuresis vs Water Diuresis

Osmotic diuresis and water diuresis are both causes of polyuria. However, they cause increased urination through different processes. 

Osmotic diuresis occurs when the kidneys filter substances into the urine that draw more water into the urine. An example is diabetes mellitus in which the kidneys filter excessive glucose into the urine, which causes excessive urine volume.

Water diuresis or solute diuresis occurs when the collecting ducts in the kidneys are unable to reabsorb enough solute-free water, resulting in increased urine volume. Examples are diabetes insipidus and psychogenic polydipsia (compulsive water-drinking).

Diagnosis of Polyuria

Your healthcare provider can identify the cause of polyuria (excessive urination volume) based on your other symptoms, medical history, physical exam, and the results of investigations and diagnostic tests. As noted, diabetes is a common cause of polyuria, but there can also be other causes for this symptom.

Diagnostic Tests for Polyuria

Some of the tests your doctor may order to diagnose polyuria (high urine volume) include:

• Urine tests such as urinalysis, 24-hour urine collection, urine osmolality, and urine electrophoresis. 

• Blood tests such as renal function tests, electrolytes (sodium, potassium, calcium), fasting blood glucose, random blood glucose, ESR, serum protein electrophoresis, pituitary function tests, autoantibody screen, and serum lithium levels.

• Imaging studies such as ultrasound, X-ray, or CT scan of the abdomen and CT or MRI scan of the brain.

• Fluid deprivation test: A water deprivation test and desmopressin test can help to distinguish between central and nephrogenic diabetes insipidus.

• Kidney biopsy.

Treatment of Polyuria

The treatment for excessive urination volume (polyuria) depends on the underlying cause. 

Medical Treatments

You may need to be admitted to the hospital for correction of fluid and electrolyte imbalances if you become significantly dehydrated due to polyuria.

Lifestyle Changes

It’s important to seek medical care for polyuria—it can be a sign of underlying medical conditions and serious health concerns. If your doctor has found no medical causes of polyuria, the following lifestyle changes may help in managing this symptom:

• Reduce fluid intake before bedtime. Avoiding fluids 2-3 hours before going to bed can help to prevent nocturnal polyuria.

• Limit caffeine and alcohol intake, which can cause increased urination. 

• Eat a low-salt, heart-healthy diet. This can lower your risk of hypertension and kidney disease.

• Wear protective pads or underwear to manage urinary leaks. 

• Quit smoking if you smoke. Smoking can cause damage to your urinary bladder and increase the risk of urinary symptoms.

• Follow your doctor’s recommendations for the treatment of diabetes and other medical conditions that can cause polyuria.

• Talk to your doctor about your medications. Some medications can lead to an excessive amount of urination. Your doctor may change the dose, change the timing of the dose, or switch you to different medications if you have increased urine production as a side effect of your medications.