Diabetes Insipidus

Diabetes Insipidus is also one form of diabetes where large amount of severely dilute urine is excreted. This is also an endocrine disease like diabetes mellitus. But instead of insulin the problem the hormone that causes this type of diabetes is an antidiuretic hormone (also known as ADH or vasopressin). Either this hormone is deficient in the body or the kidneys are indifferent to it and hence the kidneys are not able concentrate urine.

Antidiurectic or arginine vasopressin which is also known as argipressing is a human hormone. This hormone is released in the body when there is low water in the body. This hormone causes the kidneys to conserve water by concentrating the urine. In this process it is made sure that no salts are consereved and induces vasoconstriction so as to raise the blood pressure.

The classical symptoms of diabetes insipidus are excessive urination (which may continue throughout the day and night.) and extreme thirst. Most of the symptoms of diabetes insipidus are similar to untreated diabetes mellitus with a few disticntions. The urine in case of diabetes insipidus is not sweet like in the case of diabetes mellitus. Also, the condition of hyperglycemia or elevated blood sugar level is not seen in case of diabetes insipidus and blurry vision is a rarity.

Diabetes insipidus can interfere with appetite, wieght gain and growth in children. Also, children may show signs of fever, vomitting or diarrhea. Untreated adults may be healthy for years together as long as they have enough water to balance the urinary losses. But, still there is a risk of dehydration.

Diabetes insipidus is further classified as:

Central Diabetes Insipidus: Damage to the hypothalamus or pituitary gland (because of which the feeling of thirst may be completely absent.) due to stroke, tumor, neurosurgery or some other rare causes is the reason for this type of diabetes.

Nephrogenic Diabetes Insipidus: When the kidneys fail to respond to ADH this form od diabetes insipidus is caused. Hereditory is a rare cause for this type of diabetes. Men are more susceoptible to this form of diabetes. Sometimes aquired forms of this disease are found in people. This happens as a side effect to some other medications while in some other cases no particular reason is found to be the cause.

Dispogenic Diabetes Insipidus: When there is a defect or damage to the thirst machanism of the body (which is located in the hypothalamus), dispogenic diabetes insipidus occurs. Due to this defect the person affected feels an increased amount of thirst and hence consumes more fluid. This results in the suppression of ADH secretion and urine excreation increases.

Gestational Diabetes Insipidus: As the name suggests, this form of diabetes occurs only during pregnancy. Vasopressinase (this is produced in the placenta) produced by all pregnant women breaks down ADH. But when assumes an extreme form is assumes the form of gestational diabetes insipidus. However in very rare cases gestational diabetes insipidus is caused due to abnormality in the thirst mechanism.

While central diabetes insipidus and gestational diabetes insipidus respond to desmopressin, it is ineefective in case of nephrogenic diabetes insipidus. Instead, the diuretic hydrochlorothiazide (HCT or HCTZ) or indomethacin is used in the case of nephrogenic diabetes insipidus. But it is certain that the patient should be constantly reminded to drink fluids.