Polyuria is characterized by a urine volume in excess of 2 l/m 2 /24 h or approximately 150 ml/kg/24 h at birth, 100-110 ml/kg/24 h until the age of 2 years and 40-50 ml/kg/24 h in the older child and adult.|In many patients, CDI is caused by the destruction or degeneration of neurons originating in the supraoptic and paraventricular nuclei..