Polyuria

Polyuria is a condition usually defined as excessive or abnormally large production and/or passage of urine (at least 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.

Polyuria is physiologically normal in some circumstances, such as cold diuresis, altitude diuresis, and after drinking large amounts of fluids.

Causes
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 primary polydipsia (excessive fluid drinking), central diabetes insipidus and nephrogenic diabetes insipidus.

Polyuria may also be due to e.g. diabetes insipidus, hypercalcemia) or various chemical substances (diuretics, caffeine, alcohol). 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 ADH, angiotensin II and aldosterone.

Cold diuresis is the occurrence of increased urine production on exposure to cold, which also partially explains immersion diuresis.

Substances that increase diuresis are called diuretics.

Substances that decrease diuresis allow more vasopressin or antidiuretic hormone (ADH) to be present in the kidney.

High-altitude diuresis occurs at altitudes above 10,000 ft 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.

List of causes

 * increase in fluid intake, especially water
 * diuretic drugs
 * 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.)
 * diabetes mellitus
 * diabetes insipidus
 * psychogenic polydipsia
 * high doses of riboflavin (vitamin B2)
 * high doses of vitamin C
 * cold diuresis
 * Cerebral salt-wasting syndrome
 * altitude diuresis
 * interstitial cystitis
 * interstitial nephritis
 * lupus erythematosus or other connective tissue disease related cystitis
 * Sjögren's syndrome
 * Postural orthostatic tachycardia syndrome (POTS)
 * renal tubular acidosis
 * Fanconi syndrome/renal glycosuria
 * hypercalcaemia
 * hyperthyroidism
 * hypopituitarism
 * hypogonadism
 * Conn's disease (Primary aldosteronism)
 * pregnancy
 * reactive arthritis/Reiter's syndrome
 * glomerulonephritis
 * squamous cell carcinoma of lung (a paraneoplastic consequence)
 * hypoaldosteronism
 * hypokalemia
 * polydipsia
 * congestive heart failure
 * Cushing's syndrome
 * Addison's disease
 * intestinal obstruction (occurs after toxins begin to be absorbed from the damaged intestine)
 * hyperparathyroidism
 * acromegaly
 * polycythemia
 * partial obstruction of the urinary tract
 * pheochromocytoma
 * side effect of lithium (see lithium thirst)
 * liver failure/ cirrhosis
 * pyometra in certain animals or appendicitis in humans
 * neurologic damage
 * urinary tract infection - although it more commonly causes frequent passage of small volumes of urine rather than a large volume
 * emphysematous cystitis
 * post supraventricular tachycardia
 * migraine
 * Use of a corticosteroid such as prednisone
 * nephronophthisis
 * Hyperglycaemia (often secondary to diabetes mellitus)
 * Hypoxia
 * Hypovolemia
 * Chronic Renal Failure
 * Removal of Urinary Obstruction
 * Healing Acute Tubular Necrosis
 * Forced diuresis
 * Osmotic diuresis
 * Rebound diuresis
 * Immersion diuresis