Diabetes Insipidus vs SIADH: Differences and Similarities to Manage Fluid Imbalances

Is Diabetes Insipidus vs SIADH the same disease?

Diabetes insipidus vs SIADH are not the same diseases. They both are different in the sense that diabetes insipidus is associated with little to no release of an antidiuretic hormone called ADH, resulting in frequent urination. Whereas SIADH causes excessive release of ADH, resulting in water retention.

What is Diabetes Insipidus?

Further discussing Diabetes Insipidus VS SIADH, Diabetes Insipidus is a rare condition where the body cannot regulate water. It makes the body produce excessive amounts of urine. People with DI process up to 20 quarts of urine, compared to the average person’s 1 to 3 quarts. This condition, known as polyuria, causes frequent urination.

Types of Diabetes Insipidus

There are four types of Diabetes Insipidus including:

Central Diabetes Insipidus

Central diabetes insipidus results from Vasopressin not producing enough in the brain. The region of the brain that is responsible for the production and release of Vasopressin is Hypothalamus. Hypothalamus situates near to pituitary gland, and when the levels of ADH drop, this gland releases Vasopressin into the system. Vasopressin regulates water retention in the body. Hence, if the body cannot produce ADH, the water eliminates through urine.

Causes of Central Diabetes Insipidus include:

Nephrogenic Diabetes Insipidus

In this condition, the body produces the required Vasopressin. However, the kidneys lack response to the hormone as they should.

Causes of Nephrogenic Diabetes Insipidus Include:

Dipsogenic Diabetes Insipidus

In dipsogenic diabetes insipidus, Hypothalamus issues make a person excessively thirsty, resulting in more water intake and frequent urination.

Causes of Nephrogenic Diabetes Insipidus include:

Gestational Diabetes Insipidus

GDI is a rare disorder occurring in women pregnant with more than one baby. Placenta releases enzymes that break down Vasopressin in the body, hence causing Gestational Diabetes Insipidus. The causes of Gestational Diabetes Insipidus include:

Which Drug Causes Diabetes Insipidus?

Taking the discussion on Diabetes Insipidus VS SIADH further, Lithium is a drug that treats bipolar disorders and Mania. However, long-term use of Lithium causes Nephrogenic Diabetes Insipidus, as it alters kidney functions. In addition, kidneys can no longer regulate Vasopressin in the body. However, in some cases stopping Lithium restores kidney functions. In many cases, the damage to the kidneys is permanent.

Diagnosis of Diabetes Insipidus

Taking Diabetes Insipidus VS SIADH further, Physicians run elaborate tests to identify the type and cause of Diabetes Insipidus.

Diabetes Insipidus labs include:

Urine Analysis

A urine analysis shows if your urine is too diluted or concentrated. Moreover, it tells glucose levels in the blood, which is high when a patient has diabetes mellitus.

Blood Tests

Blood tests help determine sodium levels in the blood which helps in diagnosing diabetes insipidus. High blood sodium levels indicate Diabetes Insipidus.

Water Deprivation Test

The test involves not drinking water or any liquids for several hours. The physician checks the frequency of urination during analysis, monitors weight, and performs blood analysis. In some cases, your physician may give you desmopressin. This test helps in determining the type of diabetes insipidus.


Magnetic resonance imaging involves magnetic and radio waves to give images of brain tissues and cells. In this instance, MRI helps identify damages to Hypothalamus or pituitary glands that may be causing diabetes insipidus.

Stimulation Test

During this test, a physician injects you with solutions that stimulate the release of Vasopressin. As Vasopressin releases in the body, another hormone called copeptin is released simultaneously. This test helps suggest that the disease is, in fact, diabetes insipidus.

Treatment of Diabetes Insipidus

Treatment of Diabetes Insipidus includes drinking liquids to prevent dehydration. However, this can cause many other problems,  for example, low sodium levels. Hence, your physician may refer you to an endocrinologist for proper treatment. Some specific treatments are:

Central Diabetes Insipidus

Physicians treat central diabetes insipidus with desmopressin. Desmopressin is a human-made hormone that replaces Vasopressin in your body and performs its functions. Moreover, Desmopressin is either injected or taken by mouth.

Nephrogenic Diabetes Insipidus

In some cases, nephrogenic diabetes insipidus goes away on its own. However, if a medicine is causing nephrogenic diabetes insipidus, switching them can be a solution.

Keeping calcium and potassium levels regulated in your blood also helps with nephrogenic diabetes insipidus.

The physician may also prescribe a drug called thiazide, which may lower the frequency of urination.

Dipsogenic Diabetes Insipidus

Diabetes Insipidus VS SIADH: An effective way to treat Dipsogenic DI is yet to reach us. However, there are some conventional ways to overcome the symptoms. For example, sucking on ice chips helps with frequent thirst.

In addition, your physician may also advise you on taking small Desmopressin doses. Desmopressin helps in controlling urination.

Gestational Diabetes Insipidus

Diabetes Insipidus VS SIADH: Desmopressin is the drug of choice to treat gestational DI. Moreover, it is safe to take during pregnancy. The mother’s placental hormones do not affect Desmo as they do Vasopressin, so it becomes an effective treatment.

Albeit, gestational DI goes away once the mother gives birth. However, it may reappear if the mother gets pregnant again.

What is SIADH (Syndrome of Inappropriate Antidiuretic Hormone Secretions)

Diabetes Insipidus VS SIADH: SIADH is a condition where the body produces an excessive antidiuretic hormone (ADH). ADH helps kidneys regulate water retention in the body. Hence, excessive production of ADH leads to water retention in the body.

SIADH Signs and Symptoms

Diabetes Insipidus VS SIADH: Signs and symptoms of SIADH vary from person to person. However, more severe symptoms include:

SIADH Diagnosis

There are no tests to diagnose SIADH. However, physicians perform tests to check ADH levels in the body, but the results may take up to 2 weeks to come out. In addition, a physician may run tests to cheche then checks the fluid status in the body. Some of the lab tests that help diagnose SIADH are:

If your child has Siadh signs and symptoms, the physician may order lung and brain imaging.

Treatment for SIADH

Your doctor will choose a specific course of SIADH treatment based on:

In the case of Diabetes Insipidus VS SIADH, SIADH treatment follows fluid and water restrictions. However, the fluid restriction might need to be permanent if the problem is chronic. SIADH treatment also consists of:

Diabetes Insipidus vs SIADH: CONCLUSION

In conclusion, Diabetes Insipidus VS SIADH are two different diseases. However, the reason for both disorders is a similar hormone. Where SIADH results from an overabundance of ADH in the body for several reasons, Diabetes Insipidus occurs when ADH is low in the body.

Moreover, in Diabetes Insipidus, due to low levels of ADH, less urine output is made, resulting in higher blood sodium levels, high blood pressure, and dehydration. However, in SIADH, due to an overproduction of ADH, urine output is higher, resulting in low sodium and potassium blood levels and dehydration. However, there are treatments available for both diseases. Book an in-clinic appointment with Saad, MD to get your health in check.