Diabetes insipidus is a group of water balance disorders characterized by frequent urination of more than 3 liters/day due to reduced water reabsorption by the kidneys, caused by a lack of excretion or the body's resistance to antidiuretic hormone of the posterior pituitary gland. It is divided into 2 types: central diabetes insipidus (CDI) and nephrogenic diabetes insipidus (NDI).