Diabetes Basics
Insipidus: A Rare But Troublesome Form Of Diabetes
Diabetes insipidus (DI) is a rare kind of
diabetes that causes frequent urination. The large volume of urine is
diluted, mostly water. To make up for lost water, one may end up
drinking large amounts of water. In this condition the patient urinates
frequently, even at night, which can disrupt sleep or cause bed wetting
occasionally. Excessive excretion of abnormally large volumes of dilute
urine may result in dehydration if the patient doesn't drink enough
water. Children with DI may be irritable or listless and may have fever,
vomiting, or diarrhea.
Although diabetes
insipidus and diabetes mellitus are unrelated, they can have similar
signs and symptoms, like excessive thirst and excessive urination.
When
fluid regulation system works properly, kidneys make less urine to
conserve fluid when the body is losing water. When this precise system
for regulating the kidneys' handling of fluids is disrupted, diabetes
insipidus occurs. Central DI is the most common form of DI resulting
from damage to the pituitary gland that disrupts normal release and
storage of ADH. To treat the ADH deficiency a synthetic hormone called
desmopressin can be taken by an injection, a nasal spray, or a pill.
Another
form of DI is Nephrogenic DI. It is a result of kidney's inability to
respond to ADH because of various disorders including polycystic kidney
disease, sickle cell disease, and kidney failure. A drug called
hydrochlorothiazide (also called HCTZ) or indomethacin is used for it's
cure. HCTZ is sometimes combined with another drug called amiloride.
Dipsogenic
DI is a third type caused by a defect in or damage to the thirst
mechanism, which is located in the hypothalamus. This defect results in
an abnormal increase in thirst and fluid intake that suppresses ADH
secretion and increases urine output. This fluid "overload" can lead to
water intoxication, a condition that lowers the concentration of sodium
in the blood and can seriously damage the brain.
A fourth type of DI occurs only during pregnancy. Gestational DI
occurs when an enzyme made by the placenta destroys ADH in the to be
mother. Most cases of gestational DI can be treated with desmopressin.
In rare cases, however, an abnormality in the thirst mechanism causes
gestational DI, and desmopressin should not be used.
With the help of urine analysis and fluid deprivation test, DI
can be diagnosed. The urine of a person with DI will be less
concentrated. A physician evaluates the concentration of urine by
measuring how many particles are present in a kilogram of water or by
comparing the weight of the urine to an equal volume of distilled water
(specific gravity). Fluid deprivation test helps determine whether DI is
caused by excessive intake of fluid, a defect in ADH production, or due
to a defect in the kidneys' response to ADH.
Although it's a rare
disease, one must notice it's symptoms as it may even lead to grave
consequences.