Diabetes insipidus is a rare disorder characterized by intense thirst, despite drinking fluids (polydipsia), and the excretion of large amounts of urine (polyuria).
In most cases, the disorder is the result of the body not properly producing, storing or releasing a key hormone but it can also occur when the kidneys cannot properly respond to that hormone. In rare cases, diabetes insipidus can occur during pregnancy (gestational diabetes insipidus).
There are available treatments to relieve the thirst and normalize the urine output.
Symptoms of diabetes insipidus include:
- Intense thirst
- Excretion of an excessive amount of diluted urine even at night (nocturia and bed-wetting
Symptoms of diabetes insipidus in infants and young children may include:
- Unexplained fussiness or inconsolable crying
- Unusually wet diapers
- Fever, vomiting or diarrhea
- Dry skin with cool extremities
- Delayed growth
- Weight loss
Diabetes insipidus occurs when the body cannot regulate the management of fluids. Normally, the kidneys remove excess body fluids from the bloodstream through urine.
The volume and composition of body fluids are balanced through the combination of oral intake and excretion by the kidneys. The rate of fluid intake is largely influenced by thirst. The rate of fluid excreted by the kidneys is largely influenced by the production of anti-diuretic hormone (ADH) also known as vasopressin.
ADH is released into the bloodstream when the body becomes dehydrated. ADH concentrates the urine by stimulating the kidney tubules to release water back into the bloodstream rather than excreting as much water into the urine.
The way in which the system is disrupted determines the form of diabetes insipidus:
- Central diabetes insipidus: this is caused by damage to the pituitary gland or hypothalamus, most commonly due to surgery, tumor an illness, inflammation or a head injury. The damage disrupts the production, storage and release of ADH
- Nephrogenic diabetes insipidus: this type occurs due to a defect in the kidney tubules making the kidneys unable to properly respond to ADH. The defect may be genetic or the result of a chronic kidney disorder or the use of certain drugs.
- Gestational diabetes insipidus: this form of the disorder occurs only during pregnancy when an enzyme made by the placenta destroys the ADH in the mother.
- Primary polydipsia: also known as dipsogenic diabetes insipidus or psychogenic polydipsia may cause excretion of large amounts of dilute urine. The underlying cause of this type is excessive intake of fluids.
The risk factors of diabetes insipidus mainly refer to nephrogenic diabetes insipidus that is present at or shortly after birth. This type has a genetic cause that permanently alters the kidneys’ ability to concentrate the urine. This form of the disorder usually affects males.
Dehydration that leads to:
- Dry mouth
- Muscle weakness
- Low blood pressure (hypotension)
- Elevated blood sodium (hypernatremia)
- Sunken appearance to the eyes
- Rapid heart rate
- Weight loss
Diabetes insipidus can also cause an electrolyte imbalance. This can cause the following symptoms:
- Fatigue or lethargy
- Loss of appetite
- Muscle pains