In medicine, polyuria is a condition characterized by the passage of large volumes of urine (at least 2.5 L over 24 hours in adults).http://www.nlm.nih.gov/medlineplus/ency/article/003146.htm

Polyuria is sometimes used to refer to urinary frequency, or frequent urination, irrespective of the volume of urine passed.

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 of polyuria

• 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; etc.)
• diabetes mellitus
• diabetes insipidus
• psychogenic polydipsia
• high doses of riboflavin (vitamin B2)
• high doses of vitamin C
• cold diuresis
• altitude diuresis
• interstitial cystitis
• interstitial nephritis
• lupus erythematosus or other connective tissue disease related cystitis
• Sjögren's syndrome
• renal tubular acidosis
• Fanconi syndrome/renal glycosuria
• hypercalcaemia
• hyperthyroidism
• hypopituitarism
• 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)
• hypercalcemia (most commonly from cancer)
• hyperparathyroidism^[1]
• 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 corticosteroids such as prednisone

References

1. ↑ eMedicine - Hyperparathyroidism : Article by James LaBagnara