CAUSES — In the absence of a glucoseinduced osmotic diuresis in uncontrolled diabetes mellitus, there are three major
causes of polyuria in the outpatient setting, each of which is due to a defect in water balance leading to the excretion of
large volumes of dilute urine (urine osmolality usually below 250 mosmol/kg): primary polydipsia, which is primarily seen in
adults and adolescents; central diabetes insipidus (DI); and nephrogenic DI [1].