Diabetes Insipidus Treatment

Diabetes insipidus is a relatively rare condition in which the body lacks enough antidiuretic hormone (ADH), which is also called vasopressin. Normally, ADH is secreted by the hypothalamus and it sends a signal to the kidneys to hold onto water.  When an individual has diabetes insipidus, they lack enough ADH or vasopressin so that the kidneys flush water out of the system, leading to excessive fluid loss and dehydration.

Causes of Diabetes Insipidus

As mentioned, diabetes insipidus is usually a disorder of the hypothalamus.  Under normal circumstances, the hypothalamus will put out ADH in response to dehydration, which tells the kidneys to concentrate the urine and hold onto more water.

The kidneys filter water all the time. Most of that water, however, is reabsorbed by the kidneys with only a little bit of water allowed to pass as urine.  When a person has a hypothalamic dysfunction, they don’t put out ADH and the water is not reabsorbed by the kidneys.  The end result is excessive amounts of urine being put out. The urine is usually extremely dilute.

The excretion of water is exclusively controlled by the ADH level.  If something happens to make the hypothalamus put out less antidiuretic hormone (ADH), the ADH cannot be stored in the pituitary gland, where it is then released and allowed to travel to the kidneys to concentrate the urine.  Both the hypothalamus and the pituitary gland are located in the base of the brain.

Diabetes insipidus caused by a low secretion of ADH by the hypothalamus is known as “central diabetes insipidus”.  When there is enough ADH but the kidneys don’t respond to it, it is known as “nephrogenic diabetes insipidus”.  The term, “nephrogenic” refers to the condition being related to the kidneys.

The main causes of central diabetes insipidus is damage to the hypothalamus or pituitary gland.  This can be the result of any one of the following conditions:

• Problems with heredity
• Infection
• Surgical removal of the hypothalamus or pituitary gland
• Stroke that reduces the blood supply to the pituitary gland or hypothalamus
• Head injuries that damage the pituitary gland or hypothalamus.
• Infection of the brain affecting the pituitary gland or hypothalamus.
• Brain tumors near the pituitary gland or hypothalamus.

Causes of Nephrogenic Diabetes Insipidus

As mentioned, this is from a defective pair of kidneys.  ADH levels will be normal or high but the kidneys do not recognize it and they won’t hold onto water.  This is a rare condition that can be caused by hereditary problems, some kinds of drugs, elevated calcium levels (hypercalcemia), and diseases of the kidneys (such as polycystic kidneys).

Symptoms of Diabetes Insipidus

Common symptoms of diabetes insipidus include having an excessive thirst with the constant need to drink water and cravings for water, excessive frequency of urination (at least once per hour day or night), and excessive volumes of urine.  The patient may show signs of dehydration from lack of water in the body.

Testing for Diabetes Insipidus

If it is suspected that the patient has diabetes insipidus, the doctor can order blood and urine testing to see what the hypothalamus, pituitary gland, and kidneys are doing.  Common tests for diabetes insipidus include the following:

• Urine output measurement—this will be excessive in diabetes insipidus.
• Urine concentration and osmolarity—this will be low in diabetes insipidus.
• Urinalysis—this will show dilute urine.
• MRI of the head—this can show dysfunction or tumors in the brain or pituitary gland.
• Desmopressin (DDAVP) challenge—this gives ADH exogenously and looks for an increase in concentration of urine
• Blood sodium level and blood osmolarity level—these will be abnormal in diabetes insipidus.

Treatment of Diabetes Insipidus

If the condition is caused by an underlying condition, this is treated so that the secondary diabetes insipidus is managed. If the condition is central diabetes insipidus, the only real treatment is to provide the patient with desmopressin, which is the same thing as vasopressin.  It can be given as a tablet, a nasal spray, or as an injection.

If the person has nephrogenic diabetes insipidus from some type of medication, this can be resolved by stopping the medication altogether.  This may or may not turn around the problem as some medications can cause permanent damage to the kidneys.

If the person has genetically-based diabetes insipidus or nephrogenic diabetes insipidus, the best treatment is to drink plenty of water so as to make up for the lost water in the urine.  There are also medications that can be given to concentrate the urine.  Anti-inflammatory medications and diuretics can be given to treat nephrogenic diabetes insipidus.

If the person cannot drink enough water to make up for the urinary loss of water, the individual may have to receive IV dextrose solution to replace the lost urine.  This can only be done in a hospital setting and is done when the condition has become an emergency.

If dextrose solution is given, hyperglycemia or high blood sugar levels can occur.  If this happens, the IV fluids must be given at a rate that is no higher than 500 to 750 ml per hour.  The patient will have high sodium levels that will be reduced by giving IV solutions that contain no sodium and that are hypo-osmolar (dilute).

Prognosis of Diabetes Insipidus

The prognosis of the disease depends on what is causing the problem.  If the disease is left undiagnosed and untreated, there can be life-threatening complications, including death from dehydration.

Complications of Diabetes Insipidus

If you have normal thirst centers in the brain and can drink enough fluids to make up for the loss of water by the kidneys, the electrolyte balance and amount of fluid in the body will be made up for and will be normal.  If, however, you don’t drink enough water, you can develop a severe problem of electrolyte imbalances and dehydration. This can be life-threatening.  If the diabetes insipidus is treated with vasopressin and you don’t have normal thirst centers in the brain, you will drink more liquids than is needed by the body and will have problems with electrolyte imbalances.

References:

• Diabetes insipidus. https://www.nlm.nih.gov/medlineplus/ency/article/000377.htm.
• Diabetes insipidus treatment and management. http://emedicine.medscape.com/article/117648-treatment.