What is diabetes insipidus?
Diabetes insipidus (DI) is a rare condition that leads to frequent urination (passing a lot of clear urine) and excessive thirst. The condition may be caused by problems with your pituitary gland and/or your kidneys. DI is not related to diabetes mellitus (type 1 and type 2 diabetes), which is when your levels of blood sugar (glucose) are too high.
How does your body regulate fluid?
The amount of fluid in your body is a balance between how much liquid you drink and how much urine you make. Your kidneys and bladder are part of the system.
Your kidneys remove extra fluid from your blood. If there' extra fluid in your system, your kidneys send it to your bladder. Your bladder stores and then excretes extra fluid as urine. If you take in less water, the kidneys make less urine and send water back into your blood. Antidiuretic hormone (ADH, also sometimes called vasopressin) is released if you get dehydrated and the sodium level in the blood rises, which helps your kidneys retain water.
How is DI diagnosed?
Your doctor has several ways to check for DI and to find the cause:
- Analysis of urine samples
- Blood tests to see how your pituitary gland is working
- A fluid deprivation test, which shows how well the kidneys are working. The test monitors the amount of urine made over the course of several hours without drinking fluids.
- You also might have an imaging test of your head (an MRI) to check for problems with your pituitary gland. Your doctor also may order genetic tests.
What are the complications of DI?
Taking too much desmopressin and/or drinking lots of fluids may cause low sodium levels in the blood, which can lead to headache, nausea, confusion, seizures or, in rare cases, death. Other complications are dehydration, low blood pressure, and high sodium levels in the blood.
There are four types of DI. The goal of treatment for all types of DI is to relieve thirst and to decrease the amount of urine being made. The specific treatment depends on the type.
|Central DI (the most common type)||Damage to your pituitary gland or hypothalamus from head injury, surgery, or tumors. This can lead to a lack of ADH.||Synthetic ADH: desmopressin, given by injection, nasal spray, or pill. In mild cases, treatment is increased water intake.|
|Nephrogenic DI||The pituitary releases enough ADH into the body but your kidneys can't respond to it. This can result from the prescription drug lithium, sickle cell disease, or genetic problems.||Anti-inflammatory medicine (indomethacin);
Medications such as water pills (HCTZ and amiloride);
Low-sodium diet (if needed);
Fluids as needed
|Dipsogenic DI||Excess fluid intake, caused by a problem with your thirst mechanism, or deliberately drinking too many fluids (may occur with mental illness). This can lead to low blood sodium and possible brain damage.||No known treatment yet except for restricting fluid intake|
|Pregnancy-related DI||A substance made by the placenta that prevents the mother's ADH from working.||Desmopressin (nasal spray or pill)|
What is the long-term outlook for people with DI?
Long-term outlook depends on the type of DI. Usually, adults don't have serious problems unless they do not have access to water or other fluids.
Questions to ask your doctor
- What is causing my DI?
- What are my options for treatment?
- What are the risks and benefits of the each treatment option?
- How long will I need treatment?
- How often will I need check-ups and blood tests?
- How much water or other fluids should I drink every day?