Antidiuretic hormone (ADH) helps regulate the amount of water in your body. It works to control the amount of water your kidneys reabsorb as they filter out waste from your blood. This hormone is also called arginine vasopressin (AVP).
Understanding Antidiuretic Hormones
Your hypothalamus, an area at the base of your brain, produces ADH. Sensors in your body detect when your blood volume changes and needs more ADH. These sensors talk to your brain and the pituitary gland releases ADH into your bloodstream.
When ADH makes it to your kidneys, it signals them to conserve water and produce more concentrated urine. The water your body retains has effects on your body, including:
- Diluting your blood
- Lowering your blood’s osmolality
- Increasing your blood volume
- Increasing your blood pressure
If this doesn’t restore the balance of water in your body, your brain also signals thirst, so you’re more likely to drink water. If this is not sufficient to restore the water balance, then thirst is also stimulated so that the affected person will drink more water.
Many health conditions affect the amount of ADH your body releases or the way your kidneys respond to it. You may have too much or too little ADH. If your body doesn’t produce enough ADH or your kidneys don’t respond to it, your body loses too much water in urine output. Signs of low ADH include:
- Excessive thirst
- Frequent urination
- High blood sodium levels
If your body produces too much ADH and water is retained, your blood volume increases and leads to symptoms like:
- Feeling nauseous
- Tired or lethargic feeling
- Low blood sodium levels
There's a test for ADH levels in your blood, but medical professionals don’t use it very often. Instead, an imbalance of ADH is diagnosed based on your medical history and other lab tests like urine, blood osmolality, and electrolytes.
If your body doesn’t produce enough ADH, it’s called diabetes insipidus and there are two types. Nephrogenic diabetes insipidus is characterized by your kidneys’ inability to respond to ADH. It may be inherited, but is also a symptom of larger health conditions.
Central diabetes insipidus refers to the condition in which your pituitary gland doesn’t produce enough ADH. It may be caused by:
- Inherited genetic defect
- Head trauma
- Brain tumor
Too much ADH is a condition called the syndrome of inappropriate antidiuretic hormone (SIADH). If you have SIADH, ADH releases into your blood sporadically. Sometimes it releases the correct amount, and other times it releases far more than your body needs.
Determining Your ADH Levels
ADH testing alone won’t diagnose your condition. However, your doctor may complete the test to distinguish between central diabetes insipidus, nephrogenic diabetes insipidus, and SIADH.
If your doctor suspects that your ADH levels are wrong, they may complete a water loading or water deprivation test. Keep in mind that ADH test results don’t diagnose any health conditions. Your doctor assesses other symptoms and lab work along with your medical history and a physical exam. You may receive treatment for another health condition, like an infection, that will, in turn, improve symptoms of high or low ADH levels.
Water deprivation test. Do not attempt to self-diagnose at home. A water deprivation test should only be performed under medical supervision. Your doctor may instruct you to stop drinking fluids for a period of time. Once the time passes, the blood test is administered.
Your doctor may inject a synthetic ADH and take blood at certain intervals to monitor your body’s response to restricted fluids alongside the additional ADH. Dehydration is possible, so talk to your doctor about any concerns you have before beginning the test.
Water loading test. Similar to the water deprivation test, this test must be performed under medical supervision. You’ll need to fast for a certain amount of time ahead of the test.
Then, your doctor has you drink specific quantities of water. They monitor changes in your blood and urine throughout the procedure. With a water loading test, your doctor anticipates that you won’t produce as much urine as you should.
Keep in mind that some medications impact your ADH levels. Talk to your doctor about any medications when you address your symptoms and concerns. Drugs and medications that impact your ADH levels include:
- Non-steroidal anti-inflammatory medications
Treating and Preventing ADH Symptoms
You may not be able to completely prevent your ADH levels from fluctuating over time, but you can maintain a healthy diet and drink plenty of water.
Treating ADH is possible. You can replace low levels of ADH by taking a synthetic form of the hormone in pill form. Your doctor may also suggest drinking more water and making changes to your diet and lifestyle.
If you take medications that impact your ADH levels, your doctor may ask you to consider alternative options. If you smoke or drink, you may need to cut back or stop altogether to see an improvement in your condition.