Diabetes insipidus, not to be confused with the more common diabetes mellitus, is a relatively rare disorder resulting from a failure to produce sufficient amounts of vasopressin, also known as antidiuretic hormone (ADH). Vasopressin, secreted by the posterior pituitary gland, helps the kidneys to reabsorb water and maintain proper fluid balance. If the pituitary fails to produce enough ADH, water is not conserved but simply passed through the kidneys and excreted, typically in very large quantities. More rarely, the kidneys fail to respond properly to ADH; this is known as nephrogenic diabetes insipidus. Dehydration is the primary health risk associated with either form. Diabetes insipidus affects both sexes equally. With proper treatment, overall prognosis is good (except in cases caused by cancer).
