Diabetes insipidus

General or Other | Endocrinology and Metabolism | Diabetes insipidus (Disease)


Description

A rare disorder that causes too much urine to be produced because the kidneys are not able to absorb the correct amount of water as the blood is being filtered. The hypothalamus in the brain produces a hormone called ADH (antidiuretic hormone) which is stored in the pituitary gland. ADH normally causes the kidneys to absorb water from the urine before it leaves the kidneys and enters the bladder.

Diabetes insipidus (DI) is a condition characterized by excessive thirst and excretion of large amounts of severely diluted urine, with reduction of fluid intake having no effect on the concentration of the urine. There are several different types of DI, each with a different cause. The most common type in humans is central DI, caused by a deficiency of arginine vasopressin (AVP), also known as antidiuretic hormone (ADH).

Although they have a common name, diabetes mellitus and diabetes insipidus are two entirely separate conditions with unrelated mechanisms, apart from the symptoms of thirst and passing large volumes of urine.

The symptoms of diabetes insipidus include:

(1) Weak muscles

(2) Dry skin

(3) Colourless urine instead of pale yellow

(4) Waking frequently through the night to urinate

(5) Excessive amounts of urine (polyuria)

(6) Constipation

(7) Extreme thirst that cant be quenched (polydipsia)

(8) Bedwetting.

Causes and Risk factors

Diabetes insipidus can be caused by a failure of the hypothalamus to produce ADH (central diabetes insipidus) or by a failure of the kidneys to react normally to ADH (nephrogenic diabetes insipidus). This disorder can cause dehydration or abnormalities of the blood chemistry (electrolytes). Diabetes insipidus is not related to the more common diabetes that causes elevated blood sugar (glucose) levels (diabetes mellitus).

Diagnosis and Treatment

Treating diabetes insipidus depends on what is causing the disease. Treating the cause usually treats the diabetes insipidus. Central diabetes insipidus is treated with desmopressin which replaces the missing ADH. Nephrogenic diabetes insipidus is managed by reducing salt intake and drinking increased water. Occasionally the water pill hydrochlorothiazide will be prescribed.

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