Diabetes Insipidus

Diabetes Insipidus:
Diabetes Insipidus is a medication condition (endocrine disorder) caused due to the deficiency of a hormone named Vasopressin, an antidiuretic hormone (ADH) that is secreted by pituitary gland in brain or development of insensitivity of kidneys to the ADH hormone. Large amount of highly diluted urine is excreted because of the inability of the kidney to concentrate the urine. The amount of urine excreted remains high even if the amount of fluid intake is reduced to any level.
(Excessive urination in medical terms is considered when a patient urinates more than 50ml of urine per kg of his/her body weight in an interval of about 2 hours or in simple words more than 14 liters a day.)

Signs and symptoms of Diabetes Insipidus:
The patient feels extremely thirsty and continues to urinate day and night in excessive amount. The blood glucose level in urine unlike diabetes mellitus is not high and doesn't taste sweet. The patient suffering from Diabetes Insipidus also experiences blurred vision. Symptoms of Diabetes Insipidus in children include problems related to the physical growth, affected hunger, weight gain, diarrhea, vomiting and fever. Excessive urination in adults can lead to dehydration if not compensated with proper intake of liquid. People suffering from Diabetes Insipidus may wake up several times in the night to urinate.

Causes:
As mentioned earlier, Diabetes Insipidus is mainly caused due to the following two reasons:1) Antidiuretic hormones deficiency in body that is secreted by hypothalamus in brain to maintain balance of water in urine and blood.2) if the kidney loses its ability to recognize the antidiuretic hormones.3) People suffering from some kind of injury or a tumor in the brain (it can be either hereditary or caused by surgery or injury)4) Diseased pituitary gland causing lowered production of ADH

Types of Diabetes Insipidus:
There are four main sub-types of Diabetes Insipidus:
Central Diabetes Insipidus: Damaged hypothalamus in patient causes abnormal behavior of thirst mechanism, leading the condition to Central Diabetes Insipidus.
Nephrogenic Diabetes Insipidus: This is caused due to inability of the kidney in identification of antidiuretic hormones.
Dispogenic Diabetes Insipidus: This is caused due to damage or improper behavior of the thirst mechanism (which is located in hypothalamus).
Gestational Diabetes Insipidus: This is a rare form of DI and occurs only during pregnancy. During pregnancy an enzyme is produced in placenta which destroys antidiuretic hormones, this can lead to deficiency of ADH if production exceeds minimum level.

Diagnosis and Treatment of Diabetes Insipidus:
Other than excess urination, Diabetes Insipidus is pretty hard to diagnose and it is even harder to confirm the underlying causes of the disease.

Your doctor may perform blood test for ADH, calcium, bicarbonate and sugar level, urine test and examine the frequency and volume of urine, Magnetic Resonance Imaging of the patient's brain etc. Your doctor may also direct you to an endocrinologist to confirm the disease.

Once it is confirmed that the patient is suffering from Diabetes Insipidus, your doctor may perform some additional tests to narrow down on the underlying cause of the disease. One such test available is Fluid Deprivation Test (includes study and analysis of fluid intake and urination, body weight and other factors) which helps in finding out if the condition is caused due to lack of ADH in blood, kidney disorder or improper fluid intake.

Your doctor may choose to administer the ADH level in your body and use a synthetic ADH hormone DDAVP which can be taken in injection, pill form and can also be inhaled. The treatment may take some time to help patient restore the normal level/volume of urination (it always depends on the response of patient's body to the treatment).

In case if the hypothalamus/pituitary gland is damaged and causing problem, your doctor may suggest you undergo a surgery to remove the damaged gland (or tumor on the gland if any). This mode of treatment is generally used in Central Diabetes Insipidus.