What is Diabetes Insipidus?: Signs, Symptoms, Causes and Treatment
What is diabetes insipidus (DI)?
Diabetes insipidus is a rare disorder which results in a water imbalance in the body. Unlike other types of diabetes such as type 1 and type 2 diabetes, which are characterized by high levels of blood sugar, DI does not result in high blood sugar. Instead, DI leads to large excretion of urine and extreme thirst even after drinking fluids. People who have severe DI can excrete up to 20 liters of urine every day. Because of the large volume of fluids that is being excreted, people with DI tend to become dehydrated if they don’t consume water.
Adults have a higher chance of developing DI although it can happen at any age. Most healthy adults urinate 4 to 7 times per day. In case you are urinating more than normal, you may require to visit a doctor for evaluation. Note that children are likely to urinate more because they have a smaller bladder compared to adults. However, if your child urinates more than 10 times every day, you should take them to see a doctor. Your doctor will do some tests to try and identify the underlying problem. Children with DI will show symptoms such as irritability, excessive thirst, dehydration, vomiting, high fever or diarrhea. In some rare cases, this condition can affect women during pregnancy and is known as gestational diabetes insipidus. DI has no cure, however, there are treatment available to help normalize urine excretion and reduce your thirst.
Signs and symptoms of diabetes insipidus
Diabetes insipidus is characterized by symptoms such as extreme thirst and excessive urination. People who have DI feel the urge to pass urine every 15 to 20 minutes. When you need to pass urine frequently and you are always thirsty, it may disrupt your sleeping pattern and daily activities. The signs and symptoms of this medical condition happen when there is insufficient amount of vasopressin, which instructs the kidneys to store water. Without this hormone too much fluid is lost via urine. If DI is not treated, it can lead to dehydration and in worst cases, coma.
The following are signs and symptoms of DI:
- Extreme thirst
- Excessive urination
- Weak muscles
- Colorless urine rather than pale
- Dry skin
It may be difficult to notice your infant has excessive thirst because they cannot speak. However, if you notice the following symptoms in children, you should visit your doctor to try and identify the cause.
- Excessive crying
- Unexplained loss in weight
- Unexpected slow growth
- Hyperthermia or high body temperature
DI happens when your body is unable to regulate fluids. Typically, your kidney is responsible for removing excess body fluids from your blood. These fluids are stored temporarily in the bladder as urine. If your fluid regulation system is functioning properly, your kidney will store fluids and excrete less urine, when you are thirsty or a little bit dehydrated. The composition and volume of our body fluids are controlled by a combination of drinking fluids and urine excretion by the kidneys. Most of the time drinking fluids happens when you are thirsty. However, your drinking habits can make you take more fluids than is necessary. Your body makes a substance known as antidiuretic hormone (ADH) which influence the amount of fluids that is excreted by your kidneys. ADH is normally produced in the hypothalamus part of the brain and stored in the pituitary fluids. This hormone is usually released into your blood when your body is dehydrated. ADH concentrates fluids in your body by triggering the kidney to release fluids back into the blood instead of excreting it as urine.
In people with DI, ADH is unable to regulate their body fluids, which allows excessive passage of urine.
There are two common types of DI
- Cranial diabetes insipidus (CDI)
- Nephrogenic diabetes insipidus (NDI)
CDI is where your body doesn’t produce enough amount of ADH which leads to excessive loss of fluids via urine. NDI is where your body produces enough amount of ADH but the kidney fails to respond to it properly. The main causes of CDI are brain tumor or severe head injury which damages pituitary glands or the hypothalamus. NDI can be acquired or developed during birth. The main cause of acquired NDI is lithium which is used to treat bipolar disorder. NDI is caused by two genetic mutations, i.e. AVPR2 gene mutation and AQP2 gene mutation.
Your doctor will need to carry out different tests such as urinalysis and a fluid deprivation test to try and identify the cause of your symptoms. Urinalysis involves taking a sample of urine to test for salt and other waste concentrations. If you have DI, your urine test will show high water concentration and low waste concentration. A water deprivation test involves checking your blood and urine samples for changes in ADH blood levels, urine output, body weight, and urine composition. This will help your doctor determine if DI is as a result of taking excessive fluids, a defect in the production of ADH or a defect in the response of the kidney to ADH. Some patients may require genetic screening to try and identify if DI is inherited from family. Magnetic resonance imaging (MRI) which involves taking an image of the brain tissue using radio and magnetic waves, may be carried out to determine if there is any damage to your brain tissue which is causing your symptoms.
Before treatment can begin, your doctor will need to determine the type of DI that is involved. If you are diagnosed with DI, the treatment you will receive will be based on the type of DI and the severity of your condition. In case you have mild DI, your doctor may advise you to take a specific amount of water, usually between 2 liters and 2.5 liters per day.
All types of diabetes insipidus require desmopressin treatment which is a synthetic form of vasopressin hormone. Desmopressin or DDAVP is an artificial hormone which is taken as pills, injection and nasal sprays to help treat DI. As you take this medication, you should consume water only when you are thirsty. Desmopressin can be used to treat central DI as well as severe gestational DI.
In case you are diagnosed with nephrogenic diabetes insipidus, treating the underlying cause may help to cure the condition. Other treatment may involve taking desmopressin medication in higher doses, together with other diuretics alone or in combination with aspirin or ibuprofen, or with medications such as indomethacin. In case the condition is as a result of medications, your doctor may advise you to stop taking the medication or replace them.
Lifestyle changes are important in treating diabetes insipidus. You may require to drink adequate amount of water so as to prevent the risk of dehydration. You can work with your doctor to determine how much fluids you should take every day.