Diabetes Insipidus

Authored by , Reviewed by Dr Adrian Bonsall | Last edited | Meets Patient’s editorial guidelines

Diabetes insipidus is a condition in which your ability to control the balance of water within your body is not working properly. Your kidneys are not able to retain water and this causes you to pass large amounts of urine. Because of this, you become more thirsty and want to drink more. There are two different types of diabetes insipidus: cranial and nephrogenic. Cranial diabetes insipidus may only be a short-term problem in some cases. Treatment includes drinking plenty of fluids so that you do not become lacking in fluid in the body (dehydrated). Treatment with medicines may also be needed for both types of diabetes insipidus.

  • Diabetes insipidus is not a very common condition. It affects about 1 in 25,000 people.
  • Diabetes insipidus can affect people of any age but it is mostly a problem that affects adults.
  • Diabetes insipidus may start during pregnancy.

The main symptoms of diabetes insipidus include:

  • Passing large volumes of urine. You may find that you can pass somewhere between 3 and 20 litres of urine per day.
  • Passing urine frequently (up to every half an hour) during the day.
  • Getting up to pass urine frequently during the night.
  • Feeling excessively thirsty, despite the fact that you seem to be drinking lots of fluids.
  • A lack of fluid in your body (dehydration). This can become a problem if you do not drink enough fluids to compensate for the amount of urine that you are passing. Severe dehydration is a medical emergency and immediate medical attention is needed.
  • Symptoms of dehydration can include:
    • Headaches.
    • Dry mouth, lips and tongue.
    • Dry skin, dizziness.
    • Light-headedness.
    • Muscle cramps.
    • Weakness.
    • Confusion.
    • in severe cases, collapse.
  • Tiredness and reduced concentration. This may be due to lack of sleep because of repeated night-time trips to the toilet.

Poor growth and weight loss may be noticed in babies with diabetes insipidus. They may also appear irritable and difficult to settle. Older children may have problems with bedwetting at night and also incontinence of urine during the daytime. They may also have poor growth and a loss of appetite, as well as tiredness.

Is diabetes insipidus dangerous?

The two most dangerous complications of diabetes insipidus are dehydration and a change in the chemical composition of body fluid (electrolyte imbalance). Diabetes insipidus can be life-threatening if it is not diagnosed and treated early enough.

Diabetes insipidus is a condition in which your ability to control the balance of water within your body is not working properly. Your kidneys are not able to regulate as well as they normally do how much water passes out in your urine. This means that you pass large amounts of dilute urine. The medical term for passing large amounts of urine is polyuria.

Because you are passing more urine (and therefore losing more fluid from your body), to try to compensate for this, you become more thirsty and want to drink more. The medical term for this increased thirst and desire to drink more is polydipsia.

If you have diabetes insipidus you can become dehydrated easily. The levels of sodium and potassium salts in your blood can also become unbalanced and too high.

There are two different types of diabetes insipidus (described below):

  • Cranial diabetes insipidus.
  • Nephrogenic diabetes insipidus.

What is the difference between diabetes insipidus and diabetes mellitus?

Diabetes insipidus should not be confused with the much more common type of diabetes called diabetes mellitus. The two conditions are not related. Diabetes mellitus can also make you feel thirsty and pass lots of urine. It occurs when the level of sugar (glucose) in your blood becomes higher than normal. In diabetes insipidus, there is no problem with the level of glucose in your blood. See the separate leaflets called Type 1 Diabetes and Type 2 Diabetes for more details.

Cranial diabetes insipidus

Cranial diabetes insipidus occurs when your brain produces or releases a reduced amount of antidiuretic hormone (ADH). ADH is also known as vasopressin. It is made in a part of your brain called the hypothalamus. It is then transported to another part of your brain, the pituitary gland, from where it is released into your bloodstream. ADH usually helps your kidneys to concentrate your urine. If less ADH is released, you will pass an increased volume of dilute urine.

Cranial diabetes insipidus can occur if your hypothalamus or pituitary gland is damaged. This causes a reduction in production and release of ADH. The causes of cranial diabetes insipidus include:

  • Head injury.
  • Cancerous (malignant) or non-cancerous (benign) tumours of your brain or pituitary gland.
  • Surgery to your brain around the region of the pituitary gland and hypothalamus.
  • Idiopathic diabetes insipidus. In this condition the cells in your hypothalamus become damaged and stop producing ADH. In many cases, the damage is thought to be due to an autoimmune problem. Normally, your body makes antibodies to fight infections - for example, when you catch a cold or have a sore throat. These antibodies help to kill the germs (bacteria or viruses) causing the infection. In autoimmune diseases your body makes similar antibodies (autoantibodies) that attack its normal cells. In this case, the cells of your hypothalamus are attacked by autoantibodies.
  • Infections including encephalitis and meningitis.
  • Some rare inherited conditions.

Cranial diabetes insipidus may just be a problem on its own. However, sometimes it can occur with other problems because the production of other hormones that are released by the pituitary gland is also affected. Cranial diabetes insipidus is sometimes called central diabetes insipidus or neurogenic diabetes insipidus.

If cranial diabetes insipidus is caused by a head injury or surgery to your brain, it may only be a problem for a short period of time, perhaps a few weeks.

Nephrogenic diabetes insipidus

The term nephrogenic refers to the kidneys. In nephrogenic diabetes insipidus, ADH is still being released by your brain but your kidneys become resistant to the effects of ADH. This means that ADH is not able to work properly to allow your kidneys to concentrate your urine. Again, this means that the following will develop:

  • Passing large amounts of diluted urine (polyuria).
  • Becoming excessively thirsty and so drinking more (polydipsia).

Nephrogenic diabetes insipidus is very rare. Causes include the following:

  • Some causes of chronic kidney disease.
  • If the level of certain medicines that you are taking becomes too high in your body, particularly a medicine called lithium.
  • Rarely, nephrogenic diabetes insipidus can be passed on through your genes.

What is the most common cause of diabetes insipidus?

Cranial diabetes insipidus is the most common type (caused by damage to the brain from infection, operation, tumour or head injury). The most common cause of nephrogenic diabetes insipidus is as a side-effect of taking lithium medicine.

Your doctor may suspect diabetes insipidus by your typical symptoms and because of other things; for example, if you have had a recent head injury, surgery to your brain, etc. In order to confirm the diagnosis, various tests are usually suggested. These can include the following.

Blood and urine tests

For example:

A water deprivation test

This is a special test where you must not drink any water or other fluids for a certain period of time (usually around 6-8 hours). The volume of urine that you produce will be measured to see if there is any change in the amount. If your body is working normally, the amount of urine that you produce should reduce if you have not drunk anything for a long time. However, if you have diabetes insipidus, there will be little change in your urine production.

Antidiuretic hormone test

After the period of fluid deprivation, you may then be given a medicine that is similar to ADH. If you have cranial diabetes insipidus, once you have been given this medicine, the amount of urine that you produce should reduce. The medicine is replacing the ADH that you are lacking. If you have nephrogenic diabetes insipidus, you may have no, or only a small, response to the medicine.

Other tests

Other tests may sometimes be suggested to look for possible causes of diabetes insipidus. For example, a magnetic resonance imaging (MRI) scan of your brain and pituitary gland.

Cranial diabetes insipidus

The underlying cause of cranial diabetes insipidus may need treating first. For example, if you are found to have a tumour affecting your hypothalamus or pituitary gland. Your doctor will be able to advise about any treatment that you may need.

Otherwise, the following may be suggested:

  • Careful control of the fluids that you drink. In mild cases, cranial diabetes insipidus may be controlled by ensuring that you are drinking enough fluid to quench your thirst and to keep the salt levels in your blood stable. You may not need any other treatment. Regular monitoring of the salt levels in your blood using blood tests will usually be suggested.
  • Desmopressin. This is a medicine that resembles ADH. It can have the same effect as ADH on your kidneys. For more information see the separate leaflet called Desmopressin.

Sometimes cranial diabetes insipidus may only last for a short period (perhaps a few weeks) after a head injury or brain surgery and so treatment may only be needed in the short term. However, other causes may mean that you need lifelong treatment for diabetes insipidus.

Nephrogenic diabetes insipidus

As mentioned above, sometimes nephrogenic diabetes insipidus can be caused as a side-effect of certain medicines such as lithium. If you are taking such a medicine and you develop diabetes insipidus, your doctor may recommend that the medicine be changed. However, only make changes to your medication on the advice of your doctor.

Nephrogenic diabetes insipidus is not caused by a lack of ADH and so giving desmopressin will not treat the condition. If you have mild nephrogenic diabetes insipidus, your doctor may suggest that you drink plenty of fluids to avoid lack of fluid in the body (dehydration). He/she may also suggest some changes to your diet to help reduce the amount of urine that you produce. For example, eating fewer salty and processed foods and fewer foods that contain protein (such as meat, fish and eggs). You may be referred to a dietician for specialist advice about your diet. You should not make changes to your diet without the advice of an expert.

If you have more severe nephrogenic diabetes insipidus, medication may be suggested, for example, a medicine called hydrochlorothiazide. This medicine can help to reduce the amount of urine that your kidneys produce.

If you have diabetes insipidus and develop runny stools (diarrhoea) and/or are being sick (vomiting), you need to ensure you drink plenty of fluids to help prevent lack of fluid in your body (dehydration). If you have any vomiting and/or serious diarrhoea, you should see a doctor. You also need to take care in hot weather because you will sweat more and so may become dehydrated more easily.

However, it is also important that you don't become overloaded with water. This can happen if you are drinking more fluids than you are passing out in your urine or if you are taking too much desmopressin. Water overload can lead to problems with the levels of salts in your blood, particularly sodium. It can make your sodium levels drop too low. Signs that you may be water-overloaded can include headaches, weight gain and dizziness. Low sodium levels can make you feel drowsy and confused and in severe cases can lead to a fit (seizure) and unconsciousness. You should see your doctor if you are concerned about any of these symptoms. To avoid this, never take more desmopressin than you need and, if you are taking desmopressin, follow the advice of your doctor about how much fluid you should drink. Also, your doctor will usually recommend regular blood tests to check on your sodium and other salt levels if you have diabetes insipidus.

It is a good idea to have a medical emergency identification bracelet or equivalent if you have diabetes insipidus. This is so that healthcare professionals know about your condition, even if you have an accident or are unwell and become unconscious and so are not able to tell them yourself.

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