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.
(See Overview of Urinary Tract Symptoms.)
Causes of Excessive or Frequent Urination
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 2 symptoms are often considered together.
The most common causes of urinary frequency are
Bladder infections (the most common cause in women and children)
Noncancerous enlargement of the prostate gland (benign prostatic hyperplasia—the most common cause in men over 50)
The most common causes of polyuria in both adults and children are
Uncontrolled diabetes mellitus (most common)
Drinking too much fluid (polydipsia)
Antidiuretic hormone helps the kidneys reabsorb fluid. If too little antidiuretic hormone is produced (a condition called ) or if the kidneys are unable to properly respond to it (), 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.
Rarely, urinary frequency is caused by spinal cord injury or disorder.
Evaluation of Excessive or Frequent Urination
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 condition
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 1 or 2 days. 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
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 or 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 infections. 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 | |
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 |
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 |
Only a doctor's examination | ||
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 adults with obesity, who may already be known to have type 2 diabetes | Measurement of blood sugar (glucose) level |
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 ADH (water deprivation test) Sometimes blood tests to measure the ADH level | |
Excessive thirst that develops gradually In people who have a disorder that may affect the kidneys (such as sickle cell disease, Sjögren syndrome, or cancer, high blood calcium level caused byhyperparathyroidism, amyloidosis, sarcoidosis Onset in the first few years of life or in children whose family members drink excess amounts of water | 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 condition | Sometimes in people known to have a mental health condition | Similar to tests for argininevasopressin deficiency |
* Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present. | ||
ADH = antidiuretic hormone; 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 of Excessive or Frequent Urination
The best way to treat excessive urination is to treat the underlying disorder. For example, diabetes mellitus
Essentials for Older Adults: Excessive or Frequent Urination
Older men often urinate frequently because the prostate usually enlarges with age (a condition called benign prostatic hyperplasia). 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 medications may contribute to excessive urination. Older adults 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. Treatments directed at benign prostatic hyperplasia include oral medications and surgery for some cases.
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.
