The production by a person of more urine than is normal for them. In an adult an output of roughly 3 litres a day would be viewed as abnormal, a condition known medically as polyuria.
A number of diseases cause abnormal amounts of some substances to be excreted in the urine; these substances draw water with them, therefore increasing the urine volume. The most important disease in this group is diabetes mellitus, in which excess glucose passes from the blood into urine, some kidney diseases, called salt-losing states, lead to excessive salt loss in the urine, with an accompanying increase in the amount of urine is also passed.
Excessive urination can also be due to diabetes insipidus. In central diabetes insipidus, the production of ADH (anti diuretic hormone) by the pituitary gland is lessened. ADH usually acts on the kidneys to concentrate the urine, so low levels of this hormone cause a marked increase in urine volume. In nephrogenic diabetes insipidus, which can result from a range of kidney disorders, usual amounts of ADH are produced but the kidneys fail to respond to this.
Excessive urination is occasionally due to psychiatric issues, which can cause an individual to drink compulsively. This leads, inevitable to a high urine output.
Caffeine and alcoholic containing drinks have a diuretic effect, which temporarily increases the urine output.
Any person who starts to pass larger amounts of urine than is normal for them should consult a doctor.
One simple diagnostic test involves restricting the individual’s fluid intake. In a compulsive drinker, urine volume quickly drops if water intake is restricted, but is a person has diabetes indipidus, urine production will continue to remain excessive. If diabetes insipidus is suspected, synthetic ADH may be given to establish the type; central diabetes insipidus improves after administration of ADH, but the nephrogenic type does not.
Chemical tests on urine can also aid diagnosis. In patients with diabetes mellitus, the glucose level in the urine and blood is high; in salt losing individuals, an excessive amount of sodium is detectable in the urine.
Treatment of excessive urination ranges according to the underlying cause