Diabetes insipidus (DI) is an uncommon disorder characterized by excretion of large quantities of dilute urine, accompanied by excessive thirst. Central DI, also known as arginine vasopressin deficiency, is the most common and serious type and occurs due to decreased antidiuretic hormone (ADH) secretion. Nephrogenic DI, also known as arginine vasopressin resistance, occurs due to failure of the kidneys to respond to ADH.

The most common clinical symptoms are polyuria and polydipsia. Other common symptoms include waking at night to urinate and bed-wetting. Infants may present with inconsolable crying, irritability, growth retardation, hyperthermia, and weight loss. Children may present with fatigue, anorexia, enuresis, and growth defects.

In adults, central DI occurs due to damage to the pituitary gland or hypothalamus, usually from a surgery complication, tumor, infection, or head injury. In children, central DI is typically inherited. In some cases, the cause of central DI is idiopathic.

There is a genetic component to nephrogenic DI, which presents at birth or shortly thereafter. This genetic cause perpetually modifies the kidneys' ability to concentrate urine. Nephrogenic DI most commonly affects males. The kidney defect in nephrogenic DI can also result from chronic diseases including polycystic kidney disease, sickle cell disease, kidney failure, partial ureteral blockage, and genetic disorders. Some medications, such as lithium and demeclocycline, may cause nephrogenic DI.

Two other forms of DI include gestational DI and primary polydipsia (dipsogenic DI). Both of these DI forms are caused by vasopressin deficiencies, not by a defect in the neurohypophysis or kidneys. Gestational DI occurs in pregnancy when a placental enzyme terminates ADH in the mother. Dipsogenic DI is caused by excessive intake of fluids. This may result from damage to the hypothalamus or mental illness.

With the exception of dipsogenic DI, most forms of DI cause the body to retain an insufficient amount of water, which can result in dehydration. Another possible complication is electrolyte imbalance.

Treatment of DI will depend on specific type. Underlying conditions should be treated if possible.

Desmopressin is commonly used to treat central DI.

When nephrogenic DI is drug-induced, the medication should be discontinued to help the patient regain normal renal function. However, some medications that have been used for a long period of time, such as lithium, may result in permanent nephrogenic DI. Both lithium-induced nephrogenic DI and inherited nephrogenic DI are treated by drinking enough fluids to match urine output. Medications that lower urine output may be suggested. Nephrogenic DI may also be treated with anti-inflammatory medicines and diuretics.

Prognosis of DI is dependent on the underlying disorder. If DI is treated, it will not cause severe health issues or result in early death.