Diabetes Insipidus (DI) is a rare condition characterised by an imbalance of fluids in the body. Here, the kidney malfunctions to produce a large volume of urine followed by the need to drink more liquids. The condition makes a person urinate ten times more than normal. It is a very uncommon kidney disorder which affects 1 out of 25000 people.

The question that arises with DI is how it is different from diabetes mellitus as in both cases, the symptoms are frequent thirst and urination. Diabetes mellitus is informally called sugar diabetes in which a person has high blood glucose in their body as a result of the body's inability to use them for energy. In patients with DI, the blood glucose level is normal but it's the kidney disfunction which causes an imbalance of fluids. So, it is possible that a person can suffer from DI without having any forms of diabetes.

Cause Of Diabetes Insipidus

Our body is made up of around 50-65% of water. There are several mechanisms in our body which help in balancing the water present in our body. Vasopressin (AVP or ADH), an antidiuretic hormone formed in the hypothalamus helps to regulate and prevent water loss from the body. The hormone also determines the thirst and how much water to take in.

When a person is thirsty or the body requires more water, the brain sends signals to produce more AVP which gives out a sensation to consume more water and minimize the urine production. On the other hand, when there's enough water in the body, the brains send signals to lower down the AVP which in turn, switches the sensation of thirst off and let extra water to pass out of the body in form of urine. In this way, the water level remains balanced in the body.

In DI, the mechanism of water regulation is hampered due to certain conditions resulting in excess urine production and thirst.

Types Of Diabetes Insipidus

There are two main types of DI.

1. Cranial or hypothalamic DI: In conditions like tumour, inflammation, surgery or accident near the pituitary gland, the cranial DI occurs. Such conditions cause the less production of AV due to which the kidney is unable to hold the water and use it resulting in excessive water loss through urine and dehydration.

2. Nephrogenic DI: Here, AVP is produced normally but the kidney is unable to respond to the signals of AVP hormones due to some malfunction resulting in poor absorption of water and more urine production. The nonresponse of the kidney is basically due to genetic mutation, chronic kidney diseases, high calcium level or medications.

Symptoms Of Diabetes Insipidus

Symptoms of DI include the following:

• Extreme thirst (polydipsia)
• Excessive urine production approx after every 15-20 minutes (polyuria)
• Tiredness
• Difficulty in focusing
• Irritation
• Dehydration
• Dry skin
• Muscle weakness
• Enuresis, repeated inability to control urine

If DI occurs in children, the symptoms are as follows:

• Growth retardation
• Crying excessively
• Hyperthermia
• Loss of appetite
• Weight loss
• Constipation

Complications Of Diabetes Insipidus

In DI, the loss of body fluid is more than usual. If the loss is greater, the main complication that occurs is dehydration which in turn, causes other symptoms. Common symptoms of dehydration are as follows:

• Dizziness
• Nausea
• Fatigue
• Dry skin
• Electrolyte imbalance
• Thirst
• Impaired mental function

Diagnosis Of Diabetes Insipidus

Following are the tests performed to detect DI:

• Medical history: To determine the patient's medical conditions (if any), recent injuries and family history of DI
• Physical examination: To check for signs of dehydration by looking at the patient's skin
• Water deprivation test: To detect whether the symptoms denote DI or diabetes mellitus
• Blood tests: To detect the amount of AVH in the blood. Also, to find out DI types
• Vasopressin test: The test is carried out to detect the type of DI
• Urinalysis: To check whether the urine is diluted or concentrated as dilute urine is a sign of DI
• MRI: To get a view of the hypothalamus and find out any problems in it

Treatment Of Diabetes Insipidus

The treatment of DI mainly depends on controlling the amount of urine.

• Treatment for cranial DI: In mild conditions, doctors may suggest drinking a particular amount of water to prevent dehydration while in severe cases, they may go for synthetic AVP in the form of pills, nasal spray or injection. However, one should use it as prescribed due to its multiple side effects like bloating, vomiting etc.
• Nephrogenic DI: This is caused mainly due to medications which are more in lithium. In such situations, an endocrinologist may suggest for some alternative medications (like thiazide diuretics) and some dietary tips like to reduce the amount of salt in food.

Apart from this, it is also treated by curing the underlying condition like a tumour which might be causing a problem to the pituitary gland.

How To Deal With Diabetes Insipidus

• Prevent dehydration by taking water wherever you go.
• Keep a note on the amount of water taken.
• Keep a medical alert card always in your pocket so that others would know about your condition in case of emergencies.