four types of Diabetes Insipidus

Diabetes insipidus is an uncommon condition characterised by polyuria (excessive urination) and polydipsia (excess thirst). At the same time, Diabetes Mellitus is due to elevated blood sugars. During the early 1670s, Thomas Willis noticed there was a taste difference between the urine produced by patients who presented with polyuria and polydipsia. This early description of diabetes insipidus led to it being considered a separate disease. In 1794, Johann Peter Frank coined the term “diabetes insipidus”; described polyuric patients excreting non-saccharide urine. A healthy adult usually urinates between 1 and 3 litres of urine daily. In comparison, people with diabetes insipidus may pass as many as 20 litres of urine daily, which is relatively too much.

Causes of Diabetes Insipidus

Diabetes insipidus is predominantly caused by abnormal levels of the Antidiuretic hormone (ADH)/vasopressin. The major role of vasopressin/ADH is to regulate body fluids.

Fluid balance in the body is a key to overall health. The fluid required by the body is provided through the food and water we consume all day. A small number of fluids are eliminated through sweat and breath. When there is a fluid overload in the body, the excess fluid is eliminated in the form of urine.

The hypothalamus in the brain produces ADH and stores it in the pituitary gland. The ADH is released into the blood, signalling the kidneys to retain water whenever there is a need for water. A smaller amount or no ADH is released when there is excess fluid in the body, and then the excess fluid is excreted through urine.

Any interruption in this usual process can lead to diabetes insipidus. Diabetic insipidus can have different causes based on the type you have.

Types of Diabetes Insipidus

There are  causes that vary among the four types of diabetes insipidus. Listed and described below:

01. Central Diabetes Insipidus

It is known to be the most prevalent type in Diabetes insipidus. It is caused when any damage/injury occurs to the pituitary gland or hypothalamus, resulting in no vasopressin production, storage, or secretion. Consequently, a large amount of fluid is excreted in the urine.

The damage to the pituitary gland or hypothalamus may be caused due to:

  • Head injury

  • Brain tumours

  • Infection/Inflammation

  • Surgery

  • Loss of blood supply to Pituitary gland

02. Dipsogenic Diabetes Insipidus

The high volume of liquid consumed may result in dipsogenic diabetes insipidus. It may suppress the secretion of vasopressin and increase urination. Some mental illnesses and certain medications can cause damage to the hypothalamus.

03. Nephrogenic Diabetes Insipidus

Nephrogenic diabetes insipidus develops when the kidneys do not normally respond to vasopressin and eliminate a large amount of fluid from the body. This may give rise to polyuria, especially at night.

Diabetic nephropathy can be inherited or develop from any of the following:

  • Chronic kidney disease

  • Medications like lithium

  • Altered levels of calcium and potassium in the blood

  • Blockage of the urinary tract

04. Gestational Diabetes Insipidus

The condition is only present during pregnancy. When the placenta releases an enzyme called prostaglandin, which breaks down vasopressin.After childbirth, the condition usually resolves by itself, but it can return in subsequent pregnancies.

Diagnosis of Diabetes Insipidus

The symptoms you present determine the type of test necessary. The following are the tests for diagnosing Diabetes Insipidus:

Urine Test

A urine sample will be taken to test the concentration of salts and other waste. This test is known as a urine-specific gravity test. The sample will display a high water concentration and minute traces of waste if you have diabetes insipidus. The specific gravity of urine will be below the normal levels.

Fluid Deprivation Test

The patient is asked not to drink water before the test. Then samples of their blood and urine are collected and measured the changes in:

  • Sodium levels in the blood

  • Blood osmolality

  • ADH levels in the blood

  • Urine output

  • Urine concentration 

In addition, synthetic ADH is administered during the test to see if your kidneys respond to the ADH.

Genetic Screening

In some cases, a genetic test can be used to determine any history of Diabetes insipidus in the family.

Treatment for Diabetes Insipidus

The treatment varies based on the type of the diabetes insipidus, as the cause for each type is different.

  • Suppose the cause of diabetes insipidus is due to any underlying condition such as a tumour, head injury, or dysfunction in the pituitary gland/hypothalamus. Above all, the underlying conditions should be treated, which automatically resolves the diabetes insipidus.

  • In case the pituitary gland/hypothalamus cannot produce any or sufficient amount of hormone-vasopressin. A synthetic form of this hormone called “Desmopressin” can be used to treat it. It is available in the form of a tablet, nasal spray, and injection.

  • Gestational diabetes insipidus usually does not require any treatment. After childbirth, the condition resolves by itself.

  • Other medications include:

    • Thiazides: They help reduce the kidney’s filtration rate, which results in decreased urine production.

    • Non-steroidal anti-inflammatory drugs (NSAIDs): They aid in reducing urine volume. They are used along with thiazides. Example: Ibuprofen

  • Some lifestyle changes that should be adopted:

    • Avoid dehydration: Take a sufficient amount of fluids to keep your body hydrated all day. Plan to carry a water bottle wherever you go.

    • Medical alert card/bracelet: All the time, carry a medical alert card in your bag/wallet or put on a bracelet that might help others identify that you are a diabetes insipidus patient and seek medical help in case of emergency.

Conclusion

Irrespective of the type of diabetes insipidus, they don’t lead to long-term abnormalities such as kidney failure or dialysis under medication. And the kidneys continue their normal functions despite diabetes insipidus. However, patients suffering from diabetes insipidus should be aware of the risk of dehydration. Thus they should always have something to drink close at hand, especially when it is hot outside or when you are exercising. Carry a medical alert card or wear a medical bracelet so that others will be aware of your diabetes insipidus in an emergency. Those around you must be aware of your condition if you suffer from dehydration.

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