Diabetes insipidus is not related to other types of diabetes, which are disorders of blood sugar and insulin regulation in the body. Instead, diabetes insipidus is characterized by a brain deficiency or disorder that causes afflicted individuals to become extremely thirsty, resulting in the need to urinate frequently.
Biology
Antidiuretic hormone (ADH), also known as vasopressin, is the key molecule in the development of diabetes insipidus. This hormone, which is normally produced in the hypothalamus, regulates the balance of water and urine during the filtering of blood in the kidneys. Diabetes insipidus occurs when either the hypothalamus doesn't make enough ADH or the kidneys can't use it properly and become unable to reabsorb water back into the bloodstream, instead releasing it into the urine. The result of diabetes insipidus is that the kidneys produce a lot of very dilute urine, up to 15 liters a day in severe cases.
Causes
Sometimes, diabetes insipidus is the result of traumatic brain injury or infection that damages the hypothalamus. It could also be caused by brain surgery or a tumor that alters this part of the brain. In some individuals, the condition is hereditary. Lithium and other medications that affect the kidneys or brain can also cause diabetes insipidus. Occasionally, pregnancy can cause gestational diabetes insipidus, caused by a placental hormone that breaks down ADH. Gestational diabetes insipidus only lasts until the baby is born. In approximately 25 percent of cases, there is no known cause, according to the American Academy of Family Physicians.
Testing
Urine and blood tests are available that look at the balance of water and urine in the body. If initial tests indicate the possible presence of diabetes insipidus, a longer test can be given in which urine and blood are tested every hour for a few hours to look at the pattern of water-urine balance. During this test, the patient cannot eat or drink anything. CT and MRI scans are sometimes ordered to take a look at the brain and determine if damage to the hypothalamus is the underlying cause of the symptoms.
Treatments
Treatment is not specifically required for diabetes insipidus. An individual with this disease should make sure to drink enough water because dehydration is a potential complication. People with diabetes insipidus caused by a hypothalamus problem may be prescribed desmopressin, a drug that mimics the activity of AHD in the body. People with diabetes insipidus caused by a malfunction in the kidneys may be given hydrochlorothiazide, a drug that helps the body balance water and salt. Anti-inflammatory medicines may also help the kidneys better process ADH.
Complications
Diabetes insipidus typically does not cause any major complications on its own, but if an afflicted person doesn't get enough fluids, there can be complications from that. Dehydration is the most common major complication for people with diabetes insipidus who do not drink enough fluids. Dehydration is characterized by dry skin, dry mouth, fever, sunken eyes, weight loss and rapid heart rate. An electrolyte imbalance can also occur in people with uncontrolled diabetes insipidus. This causes fatigue, headache, muscle aches and irritability.
