What is Diabetes Insipidus?

Diabetes Insipidus is a rare condition caused by a hormonal abnormality leading to an imbalance of fluids in the body. Contrary to common belief, Diabetes Insipidus is not related to Diabetes Mellitus and the only commonality between the two conditions being their names.

The word 'Diabetes' is derived from the Greek word meaning 'to syphon' or 'go through', referring to the large amounts of urine made and excreted in our bodies. Although both conditions have the similar symptoms of increased thirst and increased frequency of urination, the pathophysiologies causing them are completely different.

While Diabetes Mellitus causes an abnormal rise in blood sugar levels due to inability of our body to produce enough or respond normally to insulin; Diabetes Insipidus occurs due to the inability of our kidneys to stop the excretion and retain or conserve the amount of water needed, causing our body to make a lot of urine that is "insipid," or colorless and odorless.

What Causes Diabetes Insipidus?

The urinary system normally functions as blood passes through the kidneys, and filtered to remove impurities. Most of this fluid is sent back into circulation inside the body, while the rest along with the impurities is excreted in the form of urine.

This process of ensuring that most of the fluid is recirculated back into the body is regulated by a hormone called vasopressin or Antidiuretic Hormone (ADH) which is manufactured in the hypothalamus and stored in the pituitary gland of our brain. The body produces more ADH when it is dehydrated or losing blood pressure and this increase in ADH makes the kidneys hold onto more water instead of releasing it as urine.

Fluid imbalance in the body can occur under two circumstances; either the brain is not producing a sufficient amount of ADH or something is preventing the ADH hormone from providing its full effect. There are multiple factors that can cause the two circumstances mentioned above; namely

1. Nephrogenic Diabetes Insipidus

When the kidneys' structure is defective, and thus the kidneys cannot work properly with ADH.

2. Primary Polydipsia

Dipsogenic diabetes insipidus is another name for this condition. It is responsible for the production of large quantities of diluted urine. It occurs when the thirst regulation is faulty. It has been found that this condition can be linked to mental disorders.

3. Central Diabetes Insipidus

Any damage or injury to the pituitary gland or hypothalamus that affects ADH storage or production can result in this condition. Sometimes inherited genetic factors can also cause central diabetes insipidus.

4. Gestational Diabetes Insipidus

Even for diabetes insipidus, this particular form of the disorder is rare. This occurs when an enzyme produced by the placenta destroys the ADH made by the mother’s body.

Symptoms of Diabetes Insipidus

Diabetes insipidus results in body fluid imbalance. A healthy adult produces about 1 or 2 litres of urine in a day. But diabetes insipidus can make the individual produce and void almost 15 - 19 litres of urine daily. Hence all its Symptoms are also related or associated with the loss of body fluids.

• The need to pee frequently may cause a feeling of tiredness and irritability.
• The huge amount of fluid loss for the body makes it difficult to focus and can disrupts one's daily routine.
• The frequent urge to urinate at night disturbs sleep patterns which can result in individuals feeling unwell and tired throughout the next day.

Additional symptoms include-

• Extreme Thirst
• Voiding large volumes of dilute or 'insipid' urine (colorless and odorless)
• Feeling the urge to urinate frequently at night
• Craving cold drinks 
• Vomiting
• Constipation
• Weight loss
• Fever

What are the Four Types of Diabetes Insipidus?

The different Types of Diabetes Insipidus are defined by its different causes.

1. Gestational Diabetes Insipidus

This is diabetes insipidus that occurs during pregnancy when an enzyme produced by the placenta destroys the antidiuretic hormone. The placenta is an important part of the foetus’ nutritional channel. This condition usually goes away after the pregnancy.

2. Central Diabetes Insipidus

If the hypothalamus and the pituitary gland are damaged due to some injury, and the production or storage of ADH is affected, it results in diabetes insipidus.

3. Nephrogenic Diabetes Insipidus

When there is some structural defect in the kidneys that prevents them from responding properly to ADH, it can often result in diabetes insipidus. Possible reasons for kidney damage can be medications, mechanical injury, blockage of the urinary tract, imbalance in the number of electrolytes, kidney diseases.

4. Dipsogenic Diabetes Insipidus

Sometimes, the thirst mechanism that is regulated by the hypothalamus does not function properly. This causes the individual to feel extremely thirsty and produce copious amounts of urine. Dipsogenic diabetes insipidus is also known to be associated with certain mental health disorders too.

How do you Test for Diabetes Insipidus?

The main Tests used to diagnose Diabetes Insipidus are -

1. Magnetic Resonance Imaging (MRI)

An MRI is a non-invasive imaging technique that uses a magnetic field to create accurate brain tissue images, that help identify any abnormalities in the pituitary gland or the hypothalamus.

2. Water Deprivation Test

In cases of low water intake, our body produces the Anti-diuretic hormone (ADH) which prevents dehydration by restricting the amount of fluid lost in the urine. The Water Deprivation Test involves monitoring an individual who has not consumed any fluids over several hours, where along with assessing the concentration of urine/blood, urine output, measuring the amount of ADH produced is the key parameter to determine whether the body is producing adequate amounts of the hormone.

3. Genetic Screening Test

A family history of the disorder may need to be taken to determine whether an individual is at risk of having the condition of diabetes insipidus.

Risk Factors and Complications

Diabetes insipidus occurs more frequently in Men, but the gene can also be passed onto offspring by carrier mothers. Diabetes Insipidus can lead to following complications -

• Dehydration occurs due to the loss of a large quantity of bodily fluids, leading to a Dry mouth, changes in skin quality, fatigue, and a constant feeling of thirst.
• Electrolyte imbalance resulting in Nausea,Vomiting, General Weakness, Lack of Concentration, Frequent Muscle Cramps, and a Poor appetite.

Bottomline

Diabetes insipidus is a rare condition that does not have a cure yet. However it can be managed through medication and good nutrition. Most common medication prescribed for is the a man-made hormone called desmopressin, which replaces the vasopressin body is not making. Another way to manage Diabetes insipidus is by targeting and reducing the severity of symptoms. Drink enough liquids to prevent dehydration. Suck on ice chips or sugar free candies to moisten your mouth and increase the flow of saliva to reduce thirst and dry mouth. Nephrogenic diabetes can be managed by following a diet that is low in salt or protein  in order to help your kidneys make less urine and taking steps to balance the amount of calcium or potassium in your body. Most individuals with diabetes insipidus can prevent serious problems and live a normal life by keeping symptoms under control, being consistent with taking medication and most importantly, following the recommendations given by the health care professional or specialist.