Polyuria

Polyuria is a persistent, large increase in urine output, usually associated with nocturia. It must be distinguished from frequency of micturition with the passage of small volumes of urine. Documentation of fluid intake and output may be necessary.

Polyuria is the result of an excessive (hysterical) intake of water, an increased excretion of solute (as in hyperglycaemia and glycosuria), or a defective renal concentrating ability or failure of production of ADH.

Polyuria is a highly subjective symptom and one which presents rather less often than urinary frequency. The causes of polyuria listed here are also causes of polydipsia — the only causes of true polydipsia not included are those due to dehydration.

Polyuria is usually accompanied by excessive drinking i.e. polydipsia.