Polyuria

Definition
Polyuria – a condition in which the daily diuresis is more than 2.5 liters. Polyuria is differentiated into osmotic and aqueous.

Classification
In osmotic polyuria, the patient excretes osmotically active substances, which, after a concentration gradient, "take" water with them. The urine is then hypertonic and its density is higher. Osmotic polyuria is often found in patients with diabetes mellitus or after taking diuretics.

Aqueous polyuria is caused, for example, by excessive fluid intake; in the absence of ADH, or when the receptors for ADH are defective. The urine is hypotonic, the density is lower. Water polyuria is often found in patients with diabetes insupidus.

Causes:

 * excessive fluid intake - polydipsia - frequent to constant sensation of thirst,
 * excessive osmotic strain (diabetes mellitus)
 * deficiency of antidiuretic hormone (diabetes insipidus centralis) or antidiuretic hormone receptor (diabetes insipidus renalis),
 * chronic renal insufficiency,
 * release of extensive oedema,
 * certain congenital tubulopathies,
 * the reparative phase of acute tubular necrosis,
 * VVV (polycystosis, renal dysgenesis, etc.),
 * diuretics, theophylline preparations.

Related articles

 * Oliguria
 * Anuria
 * Diabetes mellitus
 * Diabetes insipidus

External sources

 * Polyurie (česká wikipedie)
 * Polyuria (anglická wikipedie)