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Urination, Excessive or Frequent

by Anuja P. Shah, MD

Most people urinate about 4 to 6 times a day, mostly in the daytime. Normally, adults pass between 3 cups (700 milliliters) and 3 quarts (3 liters) of urine a day. Excessive urination can refer to

  • An increased volume of urine (polyuria)

  • A normal volume of urine with the need to go more often (urinary frequency)

  • Both

Urinary frequency may be accompanied by a sensation of an urgent need to urinate (urinary urgency). Many people particularly notice polyuria because they have to get up to urinate during the night (nocturia). Nocturia also can occur if people drink too much fluid too close to bedtime, even if they drink no more than normal overall.

Causes

Some of the causes of increased urine volume differ from those of too-frequent urination. However, because many people who produce excessive amounts of urine also need to urinate frequently, these two symptoms are often considered together.

The most common causes of urinary frequency are

  • Bladder infections (the most common cause in women and children)

  • Urinary incontinence

  • Noncancerous enlargement of the prostate gland (benign prostatic hyperplasia—the most common cause in men over 50)

  • Stones in the urinary tract

The most common causes of polyuria in both adults and children are

  • Uncontrolled diabetes mellitus (most common)

  • Drinking too much fluid (polydipsia)

  • Diabetes insipidus

  • Taking diuretic drugs or substances (which increase the excretion of urine), such as alcohol or caffeine

Diabetes insipidus causes polyuria because of problems with a hormone called antidiuretic hormone (or vasopressin ). Antidiuretic hormone helps the kidneys reabsorb fluid. If too little antidiuretic hormone is produced (a condition called central diabetes insipidus) or if the kidneys are unable to properly respond to it (nephrogenic diabetes insipidus), the person urinates excessively.

People with certain kidney disorders (such as interstitial nephritis or kidney damage resulting from sickle cell anemia) may also urinate excessively because these disorders also decrease the amount of fluid reabsorbed by the kidneys.

Evaluation

Many people are embarrassed to discuss problems related to urination with their doctor. But because some disorders that cause excessive urination are quite serious, people who urinate excessively should be evaluated by a doctor. The following information can help people know when to see a doctor and what to expect during the evaluation.

Warning signs

In people with excessive urination, certain symptoms and characteristics are cause for concern. They include

  • Weakness of the legs

  • Fever and back pain

  • Abrupt onset or onset during the first few years of life

  • Night sweats, cough, and weight loss, especially in a person who has an extensive smoking history

  • A mental health disorder

When to see a doctor

People who have leg weakness should go to the hospital immediately because they may have a spinal cord disorder. People who have fever and back pain should see a doctor within a day because they may have a kidney infection. People who have other warning signs should see a doctor within a day or two. People without warning signs should schedule an appointment as soon as is convenient, usually within a few days to a week, although waiting longer is usually safe if symptoms have been developing over weeks or longer and are mild.

What the doctor does

Doctors first ask questions about the person's symptoms and medical history and then do a physical examination. What they find during the history and physical examination often suggests a cause of excessive urination and the tests that may need to be done (see Table: Some Causes and Features of Excessive Urination).

Doctors ask about

  • Amounts of fluid drunk and urinated to determine whether the problem is related to urinary frequency or to polyuria

  • How long symptoms have been present

  • Whether any other urination problems are present

  • Whether the person is taking diuretics, including beverages that contain caffeine

Some obvious findings may give clues to the cause of frequent urination. Pain or burning during urination, fever, and back or side pain may indicate an infection. In a person who drinks large amounts of beverages that contain caffeine or who has just started treatment with a diuretic, the diuretic substance is a likely cause. A man who has other problems with urination, such as difficulty starting urination, a weak urine stream, and dribbling at the end of urination, may have a prostate disorder.

Some obvious findings may also give clues to the cause of polyuria. For example, polyuria that starts during the first few years of life is likely caused by an inherited disorder such as central or nephrogenic diabetes insipidus or type 1 diabetes mellitus.

In women, the physical examination usually includes a pelvic examination and the taking of samples of cervical and vaginal fluid to check for sexually transmitted diseases. In men, the penis is examined for presence of a discharge, and doctors do a digital rectal examination to examine the prostate.

Some Causes and Features of Excessive Urination

Cause

Common Features*

Tests

Disorders that cause primarily frequent urination

Cystitis (bladder infection)

Usually in women and girls

A frequent and urgent need to urinate

Burning or pain during urination

Sometimes fever and pain in the lower back or side

Sometimes blood in the urine or foul-smelling urine

Urinalysis and urine culture

Pregnancy

Typically during the last several months of pregnancy

A doctor's examination

Sometimes urinalysis (to look for a urinary tract infection)

Prostate enlargement (benign or cancerous)

Mainly in men over 50

Slowly worsening urinary symptoms, such as difficulty starting urination, a weak urine stream, dribbling at the end of urination, and a sensation of incomplete urination

Often detected during a digital rectal examination

Blood tests to measure the PSA level

If the PSA level is elevated, biopsy of the prostate

Sometimes ultrasonography

Prostatitis (prostate infection)

A tender prostate detected during a digital rectal examination

Often fever, difficulty starting urination, and burning or pain during urination

Sometimes blood in the urine

In some cases, symptoms of a long-standing blockage in the urinary tract (including a weak urine stream, difficulty passing urine, or dribbling at the end of urination)

Urinalysis and urine culture and a digital rectal examination

Radiation cystitis (bladder damage caused by radiation therapy)

In people who have had radiation therapy of the lower abdomen, prostate, or perineum (the area between the genitals and anus) for treatment of cancer

A doctor's examination

Sometimes insertion of a flexible viewing tube into the bladder (cystoscopy) and biopsy

Spinal cord dysfunction or injury

Weakness and numbness in the legs

Retention of urine or uncontrollable loss of urine or stool (urinary or fecal incontinence)

Sometimes an obvious injury

MRI of the spine

Stones in the urinary tract (that do not block the flow of urine)

Occasional episodes of squeezing pain in the lower back, side (flank), or groin that comes and goes

Depending on where the stone is, possibly frequent urination or sudden, severe urges to urinate

Urinalysis

Ultrasonography or CT of the kidneys, ureters, and bladder

Substances that increase the excretion of urine, such as caffeine, alcohol, or diuretics

In otherwise healthy people shortly after they drink beverages containing caffeine or alcohol or in people who recently started taking a diuretic

Only a doctor's examination

Urinary incontinence

Unintentional passage of urine, most often when bending, coughing, sneezing, or lifting (called stress incontinence)

After water is inserted into the bladder, measurement of changes in pressure and the amount of urine in the bladder (cystometry)

Disorders that primarily increase the volume of urine

Diabetes mellitus if uncontrolled

Excessive thirst

Often in young children

Sometimes in obese adults, who may already be known to have type 2 diabetes

Measurement of blood sugar (glucose) level

Diabetes insipidus, central

Excessive thirst that may appear suddenly or develop gradually

Sometimes in people who have had a brain injury or brain surgery

Blood and urine tests, done before and after people are deprived of water, then given antidiuretic hormone (water deprivation test)

Sometimes blood tests to measure the antidiuretic hormone level

Diabetes insipidus, nephrogenic

Excessive thirst that develops gradually

In people who have a disorder that may affect the kidneys (such as sickle cell disease, Sjögren syndrome, cancer, hyperparathyroidism, amyloidosis, sarcoidosis, or certain inherited disorders) or who take a drug that may affect the kidneys (usually lithium, cidofovir, foscarnet, or ifosfamide)

Blood and urine tests

Sometimes a water deprivation test

Diuretic use

In otherwise healthy people who recently started taking a diuretic

Sometimes in people who take a diuretic surreptitiously (for example, competitive athletes or other people trying to lose weight)

Usually only a doctor's examination

Drinking too much fluid (polydipsia) often due to a mental health disorder

Sometimes in people known to have a mental health disorder

Similar to tests for central diabetes insipidus

*Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present.

CT = computed tomography; MRI = magnetic resonance imaging; PSA = prostate-specific antigen.

Testing

Doctors do a urinalysis and often urine culture on most people. The need for other testing depends on what doctors find during the history and physical examination (see Table: Some Causes and Features of Excessive Urination). If doctors are not sure whether the person is actually producing more urine than normal, they may collect and measure the amount of urine produced over 24 hours. If people actually have polyuria, doctors measure the blood glucose level. If diabetes mellitus is not the cause of polyuria and no other cause, such as excess intravenous fluids, is clearly responsible, other testing is necessary. The levels of electrolytes and concentration of certain salts (osmolarity) are measured in the blood, urine, or both, often after the person is deprived of water for a time and after the person is given antidiuretic hormone.

Treatment

The best way to treat excessive urination is to treat the underlying disorder. For example, diabetes mellitus is treated with diet and exercise plus insulin injections and/or drugs taken by mouth. In some cases, people can reduce excessive urination by decreasing their intake of coffee or alcohol. Doctors may also adjust the dosage of diuretics that may contribute to excessive urination.

Essentials for Older People

Older men often urinate frequently because the prostate usually enlarges with age. In older women, frequent urination is also more common because of many factors, such as weakening of the pelvic supporting tissues after childbirth and the loss of estrogen after menopause. Both older men and older women may be more likely to take diuretics, so these drugs may contribute to excessive urination. Older people with excessive urination often need to urinate at night (nocturia). Nocturia can contribute to sleep problems and to falls, especially if a person is rushing to the bathroom or if the area is not well lit.

Key Points

  • Urinary tract infections are the most common cause of urinary frequency in children and women.

  • Uncontrolled diabetes mellitus is the most common cause of polyuria.

  • Benign prostatic hyperplasia is a common cause in men over 50.

  • Excessive intake of caffeine can cause urinary frequency in all people.

Resources In This Article

Drugs Mentioned In This Article

  • Generic Name
    Select Brand Names
  • VASOSTRICT
  • VISTIDE
  • IFEX
  • FOSCAVIR
  • LITHOBID