Regulation of urine production by ADH and aldosterone
Polyuria is a condition usually defined as excessive or abnormally large production or passage of urine (greater than 2.5 or 3 L over 24 hours in adults). Frequent urination is sometimes included by definition, but is nonetheless usually an accompanying symptom. Increased production and passage of urine may also be termed diuresis.
Polyuria often appears in conjunction with polydipsia (increased thirst), though it is possible to have one without the other, and the latter may be a cause or an effect. Psychogenic polydipsia may lead to polyuria.
The most common cause of polyuria in both adults and children is uncontrolled diabetes mellitus, causing an osmotic diuresis. In the absence of diabetes mellitus, the most common causes are excessive secretion of aldosterone due to adrenal cortical tumor, primary polydipsia (excessive fluid drinking), central diabetes insipidus and nephrogenic diabetes insipidus.
Polyuria may also be due to various chemical substances (diuretics, caffeine, ethanol). It may also occur after supraventricular tachycardias, during an onset of atrial fibrillation, childbirth, and the removal of an obstruction within the urinary tract. Diuresis is restrained by antidiuretics such as vasopressin, angiotensin II and aldosterone.
Cold diuresis is the occurrence of increased urine production on exposure to cold, which also partially explains immersion diuresis.
High-altitude diuresis occurs at altitudes above 10,000 feet (3,000 m) and is a desirable indicator of adaptation to high altitudes. Mountaineers who are adapting well to high altitudes experience this type of diuresis. Persons who produce less urine even in the presence of adequate fluid intake probably are not adapting well to altitude.
In case of absence of Antidiuretic Hormone, the Distal convoluted tubule (DCT) and the Collecting duct is impermeable to water. As a result, water is not re-absorbed in the kidney. Therefore, large amount of water is lost with urine. This condition is called as Diabetes insipidus.
List of causes
- increase in fluid intake, especially water (polydipsia)
- psychogenic polydipsia
- diuretic drugs, osmotic diuresis, (forced diuresis)
- diuretic foods (foods and beverages containing caffeine, such as chocolate, coffee, tea, and soft drinks; hot spicy foods; juices high in acid; alcoholic beverages; protein shakes, etc.)
- interstitial cystitis
- interstitial nephritis
- urinary tract infection - although it more commonly causes frequent passage of small volumes of urine rather than a large volume
- chronic renal failure
- removal of urinary obstruction
- healing acute tubular necrosis
- emphysematous cystitis
- renal tubular acidosis
- Fanconi syndrome/renal glycosuria
- partial obstruction of the urinary tract
- convalescence period of acute renal failure (rebound diuresis)
- Cushing's syndrome
- Addison's disease
- use of a corticosteroid such as prednisone
- Conn's disease (primary aldosteronism)
- diabetes mellitus
- hyperglycaemia (often secondary to diabetes mellitus)
- diabetes insipidus
- congestive heart failure (healing period)
- post supraventricular tachycardia
- postural orthostatic tachycardia syndrome (POTS)
- lupus erythematosus or other connective tissue disease related cystitis
- Sjögren's syndrome
- Reactive arthritis
- high doses of riboflavin (vitamin B2)
- high doses of vitamin C
- cold diuresis
- altitude diuresis
- chronic fatigue syndrome
- hypoxia (see also sleep apnea)
- immersion diuresis
- intestinal obstruction (occurs after toxins begin to be absorbed from the damaged intestine)
- side effect of lithium (see lithium thirst)
- liver failure/cirrhosis
- pyometra in certain animals or appendicitis in humans
- Oliguria (inadequate or low urine production)
- "Urination - excessive amount". Medline Plus. United States National Library of Medicine. 27 December 2013. Retrieved 30 December 2014.
- "Polyuria". Merck Manuals. November 2013. Retrieved 30 December 2014.
- Tidy, Colin (13 December 2012). "Polyuria". Patient.co.uk. Egton Medical Information Systems. Retrieved 30 December 2014.
- "Definition of Diuresis". MedTerms. 30 October 2013. Retrieved 30 December 2014.
- "Diuresis". The Free Dictionary. Retrieved 30 December 2014.
- Hackett, Peter H. (1980). Mountain Sickness. American Alpine Club. pp. 54, 62. ISBN 0-930410-10-6.