Medical expert of the article
New publications
Polyuria and rapid urination.
Last reviewed: 04.07.2025
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Polyuria is urine output greater than 3 L/day; it should be distinguished from urinary frequency, which is the need to urinate many times during the day or night, but in normal or less than normal volumes. Either symptom may include nocturia.
[ 1 ]
Causes increased urination
Polyuria refers to the diuresis of dissolved substances or water. Causes of water diuresis include central or nephrogenic diabetes insipidus, psychogenic polydipsia, and infusions of hypotonic solutions.
Causes of solute diuresis include diabetes mellitus, saline infusions, tube feeding of high-protein formulas, resolution of urinary tract obstruction, and sodium-wasting nephropathy.
The most common urologic causes of increased urinary frequency include UTI, urinary incontinence, BPH, and urinary tract stones.
[ 2 ]
Who to contact?
Diagnostics increased urination
History may help differentiate polyuria from urinary frequency and suggest a possible cause. Polyuria due to diabetes insipidus is suggested by a history of malignancy or chronic granulomatous disease (via hypercalcemia), use of certain drugs (lithium, cidofovir, foscarnet sodium), and less common disorders (eg, sickle cell disease, renal amyloidosis, sarcoidosis, Sjögren's syndrome) whose manifestations are often more severe than and precede polyuria.
Acute onset of polyuria at a specific time suggests central diabetes insipidus. Polyuria caused by diuresis is suggested by a history of diuretic use or diabetes mellitus, and polyuria caused by polydipsia is suggested by a history of mental illness (bipolar disorder, schizophrenia).
Dysuria suggests increased urination due to UTI or stones. Previous pelvic surgery suggests incontinence, and a weak urine stream suggests BPH.
Physical examination in general has a limited role in the evaluation of polyuria and urinary frequency.
Examination for polyuria
Measuring 24-hour urine output differentiates polyuria (>3 L/day) from urinary frequency if this distinction is not obvious from the history. Output greater than 5 L/day suggests central diabetes insipidus, lithium intoxication, or polydipsia.
Urinalysis should be performed to detect UTI or glucosuria. Serum sodium can differentiate polydipsia (sodium <137 mEq/L) from diabetes insipidus (sodium >142 mEq/L). Diagnosis of diabetes insipidus is made with complete water restriction, urine volume and osmolarity, and plasma osmolarity and sodium concentration.
[ 6 ]
Treatment increased urination
Treatment for polyuria and frequent urination depends on the cause.