Diabetes Insipidus
Diabetes insipidus is a disorder characterized by extreme thirst, polydipsia, polyuria, and episodes of dehydration. This is due to absence or deficiency of antidiuretic hormone (ADH).
The cause could be idiopathic or could be secondary to lesions in the area of the posterior lobe of the pituitary gland, In the supraoptic and paraventricular nuclei of the hypothalamus and in the hypothalamic- hypophyseal tract
Other causes maybe the following:
– craniopharyngiomas
– trauma to the head
– infections of the brain like encephalitis, tuberculosis and syphilis
– leukemia and
– hand-schuller Christian syndrome
– hereditary
The patient with diabetes insipidus has a urine specific gravity that may range from 1.001-1.006 depending upon water intake.
On water and food deprivation the normal person or the person with psychogenic polydipsia
( a psychological disorder) can concentrate urine while the patient with true diabetes insipidus can do so only in a very limited way.
Persons showing abnormal urine specific gravity results are investigated to determine the cause and to treat the condition appropriately.