Diabetes insipidus (DI) is a condition in which a person produces inappropriately large amounts of urine, and becomes continually thirsty and drinks high volumes of liquids in order to replace body water. It is an entirely different condition from diabetes mellitus, the disease commonly referred to as "diabetes".
What is going on in the body?
When a person has diabetes insipidus, it is almost as if everything he or she drinks passes right through the kidneys.
The 3 forms of DI are:
- central or neurogenic, in which a defect in the brain causes a shortage of vasopressin, or antidiuretic hormone (ADH). This hormone normally tells the kidneys how much urine to release.
- nephrogenic, in which a kidney defect causes an abnormal response to vasopressin
- pregnancy-induced, in which there is a low level of vasopressin during the pregnancy
What are the causes and risks of the disease?
Diabetes insipidus may be caused by:
- a brain tumor, which keeps the body from producing enough vasopressin
- skull fracture
- head injury causing damage to the pituitary gland, the part of the brain that releases vasopressin
- craniotomy, or surgery on the head
- infections, such as encephalitis or meningitis, that damage the pituitary gland or brain
- kidney disease
- some medications, such as lithium
- inadequate release and response to vasopressin during pregnancy
What can be done to prevent the disease?
It is hard to prevent diabetes insipidus. A person can reduce his or her risk of head injury by following sports safety guidelines for children, adolescents, and adults. Early treatment of infections may also reduce the risk of DI.
How is the disease diagnosed?
Diagnosis of diabetes insipidus is usually based on the medical history, physical exam, lab tests, and imaging tests. Urine tests, including a water deprivation test, will often be used when DI is suspected. With this test, water is withheld until the person loses a certain percentage of his or her body weight. Blood and urine tests are checked routinely to evaluate the reaction of the body to the lack of water. Ultrasound,MRI, and CT scan are commonly used imaging tests to check for brain injury, tumors, or kidney problems.
Long Term Effects
What are the long-term effects of the disease?
Long-term effects depend on the cause of the diabetes insipidus. For instance, if the cause of the DI is a head injury and a person recovers completely from the injury, there may be no long-term effects.
What are the risks to others?
Diabetes insipidus is not contagious and poses no risk to others. However, those who are affected may sometimes pass the condition on to their children. Genetic counseling may be helpful to couples with a family history of diabetes insipidus.
What are the treatments for the disease?
Treatment of diabetes insipidus will depend on the cause. For instance, a person may need antibiotics for an infection. In other people, control of DI will involve use of different types of vasopressin, given as an injection into the muscle (i.e., Pitressin) or desmopressin (i.e., DDAVP) through a nasal spray.
Drinking enough fluids will also be essential to prevent dehydration. If the DI is caused by problems in the kidneys, a water pill may be prescribed to keep the fluids in the body balanced. If other conditions are present, such as head injury, treatment may involve surgery to repair or relieve pressure on the brain. Those with a brain tumor may need surgery, chemotherapy, or radiation therapy.
What are the side effects of the treatments?
Antibiotics can cause stomach upset, headache, or allergic reaction. Vasopressin may cause too much fluid to build up in the body, so fluid intake needs to be watched carefully. Surgery can be complicated by bleeding, infection, or an allergic reaction to the anesthetic. Chemotherapy may cause other side effects, including hair loss and an increased susceptibility to infections.
What happens after treatment for the disease?
A person with a head injury may require physical therapy and occupational therapy during recovery. Those with kidney problems may need further treatment, continued medication, and monitoring. A pregnant woman may need no further treatment once she delivers the baby. Those with serious diseases, such as end-stage cancer, may die if treatment does not work.
How is the disease monitored?
Any new or worsening symptoms should be reported to the healthcare provider. A person may be advised to watch the amount of fluids he or she drinks and to measure the amount of urine that he or she puts out.
Professional Guide to Signs and Symptoms, Springhouse, 1997.
Harrison's Principles of Internal Medicine, 1998, Fauci, et al.
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