Poliuric síndrome

Abstract

A poliuric syndrome (PS) is suspected when the urinary volume exceeds by 2 or 3 times the urinary volume expected for the child’s age or when after dehydration or fluid restriction an adequate urinary concentration is not produced. The volume and osmolarity of the organic fluids are precisely regulated by the activity of ADH, which regulates the water permability of the distal tubules and collecting ducts. PS is classified into 2 groups: 1) low plasma ADH levels (central CDI or neurogenic diabetes insipidus, and primary polydipsia and 2) those with normal plasma ADH (osmotic diuresis and nephrogenic diabetes insipidus NDI). The diagnosis is confirmed by the deprivation test, if the urine density and osmolarity remain low and the urine volume is not decreased, the diagnosis of CDI is considered. The vasopressin test distinguishes CDI from NDI, an increase is seen in the osmolarity and urinary flow decreases in CDI, whereas a lack of response indicates NDI. Treatment of CDI consists in hormonal replacement, while that of NDI consists in reducing protein and calorie intake, allowing the free intake of water, in addition to the use of thiazide diuretics and non-steroidal anti-inflammatories.