What is Diabetes Insipidus?

Diabetes insipidus is a condition that affects normal kidney functioning. People who have the disorder tend to have uncontrollable, insatiable thirst accompanied with excessive urine production. Symptoms are usually due to a genetic or acquired deficiency in antidiuretic hormone (ADH), though other problems such as chronic kidney disease or high calcium can also cause diabetes insipidus. Doctors can arrange for daily hormone therapy or another form of treatment after confirming the underlying cause.

There are two basic types of diabetes insipidus. Central diabetes insipidus refers to a shortage or absence of ADH in the body due to problems with the hypothalamus or pituitary gland. Inherited defects, trauma to the head or neck, and serious throat infections can all impair the body's ability to produce and secrete normal levels of ADH. The second type, nephrogenic diabetes insipidus, involves a problem with the kidneys themselves. Kidney disease, high calcium, genetic defects, and certain drugs, such as lithium, impair the ability to filter enough water back into the bloodstream.

The symptoms of both types of diabetes insipidus are similar. The most obvious symptom is excessive thirst as the body reacts to lower-than-normal water levels in the blood. A person can develop dry mouth, a raspy voice, fatigue, and headaches if he or she does not have access to fluids almost constantly. Excessive urination is partly a symptom of the underlying disease and partly due to increased fluid intake. Problems that are due to injury, infection, or kidney damage can occur at any age, but symptoms are typically present in infancy with genetic disorders.

A person who develops symptoms of excess thirst and urination that last for more than one or two days should visit a hospital. A doctor can analyze urine samples to see if they contain very high water content and very low salt levels. Blood is commonly drawn to check for infection, and magnetic resonance imaging scans may be taken of the head to check for obvious damage to the hypothalamus or pituitary. If no underlying cause is discovered, genetic testing may reveal an inherited disorder.

In order to control short-term symptoms, patients are instructed to drink a set amount of fluid each day, get plenty of rest, and report any changes in urine output to their doctors. Patients who have ADH deficiencies are usually prescribed a special synthetic version of ADH called desmopressin to take daily to stabilize kidney functioning. Surgery is needed in rare cases where one of the kidneys or the glands in the throat has been severely damaged by infection or injury.