Cause |
Common Features* |
Tests |
Disorders that cause primarily frequent urination |
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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 |
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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 |
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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 |
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) |
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Disorders that primarily increase the volume of urine |
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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 |
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 |
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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 |
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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. |
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CT = computed tomography; MRI = magnetic resonance imaging; PSA = prostate-specific antigen. |