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Diabetes insipidus is a rare condition where you produce a large amount of urine and often feel thirsty.
Diabetes insipidus isn't related to diabetes mellitus (usually just known as diabetes), but it does share some of the same signs and symptoms.
The two main symptoms of diabetes insipidus are:
In very severe cases of diabetes insipidus, up to 20 litres of urine can be passed in a day.
Read more about the symptoms of diabetes insipidus.
You should always see your GP if you're feeling thirsty all the time. Although it may not be diabetes insipidus, it should be investigated.
Also see your GP if you're:
Children tend to urinate more frequently because they have smaller bladders. However, seek medical advice if your child urinates more than 10 times a day.
Your GP will be able to carry out a number of tests to help determine what's causing the problem.
Read more about diagnosing diabetes insipidus.
Diabetes insipidus is caused by problems with a hormone called vasopressin (AVP), also called antidiuretic hormone (ADH).
AVP plays a key role in regulating the amount of fluid in the body. It's produced by specialist nerve cells in a part of the brain known as the hypothalamus. AVP passes from the hypothalamus to the pituitary gland where it's stored until needed.
The pituitary gland releases AVP when the amount of water in the body becomes too low. It helps retain water in the body by reducing the amount of water lost through the kidneys, making the kidney produce more concentrated urine.
In diabetes insipidus, the lack of production of AVP means the kidney can't make enough concentrated urine and too much water is passed from the body. In rare cases, the kidney doesn't respond to AVP. This causes a specific form of diabetes insipidus, called nephrogenic diabetes insipidus.
People feel thirsty as the body tries to compensate for the increased loss of water by increasing the amount of water taken in.
Read more about the causes of diabetes insipidus.
Diabetes insipidus affects about one in 25,000 people in the general population. Adults are more likely to develop the condition but it can occur at any age.
In rarer cases, diabetes insipidus can develop during pregnancy, known as gestational diabetes insipidus.
There are two main types of diabetes insipidus:
Cranial diabetes insipidus occurs when there's not enough AVP in the body to regulate urine production.
Cranial diabetes insipidus is the most common type of diabetes insipidus. It can be caused by damage to the hypothalamus or pituitary gland – for example, after an infection, operation, brain tumour or head injury.
In about one in three cases of cranial diabetes insipidus there's no obvious reason why the hypothalamus stops making enough AVP.
Nephrogenic diabetes insipidus occurs when there's enough AVP in the body but the kidneys fail to respond to it. It can be caused by kidney damage or, in some cases, inherited as a problem on its own.
Some medications, particularly lithium (used to help stabilise mood in some people with specific mental health conditions, such as bipolar disorder), can cause nephrogenic diabetes insipidus.
Treatment isn't always needed for mild cases of cranial diabetes insipidus. You just need to increase the amount of water you drink to compensate for the fluid lost through urination.
If necessary, a medication called desmopressin can be used to replicate the functions of AVP.
Nephrogenic diabetes insipidus is often treated with medications called thiazide diuretics which reduce the amount of urine the kidneys produce.
Read more about the treating diabetes insipidus.
As diabetes insipidus increases water loss in the urine, the amount of water in the body can become low. This is known as dehydration.
Rehydration with water can be used to treat mild dehydration. Severe dehydration will need to be treated in hospital.
Read more about the complications of diabetes insipidus.
If you have diabetes insipidus, your clinical team will pass information about you on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).
This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.
The two main symptoms of diabetes insipidus are often needing to pass large amounts of urine and feeling extremely thirsty.
If you have diabetes insipidus, you may pass pale, watery urine every 15-20 minutes. The amount of urine passed can range from 3 litres (5.2 pints) in mild cases to up to 20 litres (35 pints) in severe cases.
It's also likely that you'll feel thirsty all the time and have a 'dry' feeling that's always present, no matter how much water you drink.
If you need to pass urine regularly and always feel thirsty, your sleeping patterns and daily activities may be disrupted. This can cause tiredness, irritability and difficulty concentrating, which can affect your daily life further.
You may also feel generally unwell and 'run down' much of the time for no apparent reason.
Excessive thirst can be difficult to recognise in children who are too young to speak. Signs and symptoms that could suggest diabetes insipidus include:
In older children, symptoms of diabetes insipidus include:
Diabetes insipidus is caused by problems with a chemical called vasopressin (AVP), which is also known as antidiuretic hormone (ADH).
AVP is produced by the hypothalamus and stored in the pituitary gland until needed. The hypothalamus is an area of the brain that controls mood and appetite. The pituitary gland is located below your brain, behind the bridge of your nose.
AVP regulates the level of water in your body by controlling the amount of urine your kidneys produce. When the level of water in your body decreases, your pituitary gland releases AVP to conserve water and stop the production of urine.
In diabetes insipidus, AVP fails to properly regulate your body's level of water, and allows too much urine to be produced and passed from your body.
There are two main types of diabetes insipidus:
Possible underlying causes for both types of diabetes insipidus are described below.
The three most common causes of cranial diabetes insipidus are:
No cause can be found for about a third of all cases of cranial diabetes insipidus. These cases, known as idiopathic, appear to be related to the immune system attacking the normal, healthy cells producing AVP. It's unclear what causes the immune system to do this.
Less common causes of cranial diabetic insipidus include:
Your kidneys contain nephrons, which are tiny intricate structures that filter waste products from the blood and help produce urine. They also control how much water is reabsorbed into your body and how much is passed in the urine.
In a healthy person, AVP acts as a signal to the nephrons to reabsorb water into the body. In nephrogenic diabetes insipidus, the nephrons in the kidney aren't able to respond to this signal, leading to excessive water loss in large amounts of urine. Your thirst increases to try to balance this loss from the body.
Nephrogenic diabetes insipidus can be congenital (present at birth) or acquired (where it develops later in life as a result of an external factor). These are described in more detail below.
Two genetic mutations (abnormal changes in genes that leads to them not working properly) have been identified that cause congenital nephrogenic diabetes insipidus.
The first, known as the AVPR2 gene mutation, is responsible for 90% of all cases of congenital diabetes insipidus. However, it's still rare, occurring in an estimated 1 in 250,000 births.
The AVPR2 gene mutation can only be passed down by mothers (who may appear to not be affected) to their sons (who are affected).
The remaining 10% of cases of congenital nephrogenic diabetes insipidus are caused by the AQP2 gene mutation, which can affect both males and females.
Read more about genetics.
Lithium is the most common cause of acquired nephrogenic diabetes insipidus. It's a medication that's often used to treat bipolar disorder. Long-term lithium use can damage the cells of the kidneys so they no longer respond to AVP.
Just over half of all people on long-term lithium therapy develop some degree of nephrogenic diabetes insipidus. Stopping lithium treatment often restores normal kidney function, although in many cases the damage to the kidneys is permanent.
Due to these risks, it's recommended that you have kidney function tests every three months if you're taking lithium.
Read more about the treatment of bipolar disorder.
Other causes of acquired nephrogenic diabetes insipidus include:
See your GP if you have the symptoms of diabetes insipidus. They'll ask about your symptoms and carry out a number of tests.
You may be referred to an endocrinologist (a specialist in hormone conditions) for these tests.
If diabetes insipidus is diagnosed, the tests will also be able to identify the type you have – cranial or nephrogenic.
A water deprivation test involves not drinking any liquid for several hours to see how your body responds. If you have diabetes insipidus, you'll continue to pass large amounts of dilute urine, when normally you'd only pass a small amount of concentrated urine.
During the test, the amount of urine you produce will be measured. You may also need a blood test to assess the levels of antidiuretic hormone (ADH) in your blood.
Your blood and urine may also be tested for substances such as glucose (blood sugar), calcium and potassium. If you have diabetes insipidus, your urine will be very dilute, with low levels of other substances. A large amount of sugar in your urine may be a sign of type 1 or type 2 diabetes rather than diabetes insipidus.
After the water deprivation test, you may be given a small dose of AVP, usually as an injection. This will show how your body reacts to the hormone, which helps to identify the type of diabetes insipidus you have.
If the dose of AVP stops you producing urine, it's likely your condition is due to a shortage of AVP. If this is the case, you may be diagnosed with cranial diabetes insipidus.
If you continue to produce urine despite the dose of AVP, this suggests there's already enough AVP in your body, but your kidneys aren't responding to it. In this case, you may be diagnosed with nephrogenic diabetes insipidus.
Magnetic resonance imaging (MRI) is a type of scan that uses a strong magnetic field and radio waves to produce images of the inside of the body, including your brain.
You may need an MRI scan if your endocrinologist thinks you have cranial diabetes insipidus as a result of damage to your hypothalamus or pituitary gland.
If your condition is due to an abnormality in your hypothalamus or pituitary gland, it may need to be treated too, along with treatment for diabetes insipidus.
Treatments for diabetes insipidus aim to reduce the amount of urine your body produces.
Depending on the type of diabetes insipidus you have, there are several ways of treating your condition and controlling your symptoms.
Mild cranial diabetes insipidus may not require any medical treatment.
Cranial diabetes insipidus is considered mild if you produce approximately 3-4 litres of urine over 24 hours.
If this is the case, you may be able to ease your symptoms by increasing the amount of water you drink, to avoid dehydration. Your GP or endocrinologist (specialist in hormone conditions) may advise you to drink a certain amount of water every day, usually at least 2.5 litres.
However, if you have more severe cranial diabetes insipidus, drinking water may not be enough to control your symptoms. As your condition is due to a shortage of vasopressin (AVP), your GP or endocrinologist may prescribe a treatment that takes the place of AVP, known as desmopressin (see below).
Desmopressin is a manufactured version of AVP that's more powerful and more resistant to being broken down than the AVP naturally produced by your body. It works just like natural AVP, stopping your kidneys producing urine when the level of water in your body is low.
Desmopressin can be taken as a nasal spray, in tablet form or as a form that melts in your mouth, between your gum and your lip. If you're prescribed desmopressin as a nasal spray, you'll need to spray it inside your nose once or twice a day, where it's quickly absorbed into your bloodstream.
If you're prescribed desmopressin tablets, you may need to take them more than twice a day. This is because desmopressin is absorbed into your blood less effectively through your stomach than through your nasal passages, so you need to take more to have the same effect.
Your GP or endocrinologist may suggest switching your treatment to tablets if you develop a cold that prevents you from using the nasal spray.
Desmopressin is very safe to use and has few side effects. However, possible side effects can include:
If you take too much desmopressin or drink too much fluid while taking it, it can cause your body to retain too much water. This can result in:
Symptoms of hyponatraemia include:
If you think you may have hyponatraemia, stop taking desmopressin immediately and call your GP for advice. If this isn't possible, go to your local accident and emergency (A&E) department.
If you have nephrogenic diabetes insipidus that's caused by taking a particular medication, such as lithium or tetracycline, your GP or endocrinologist may stop your treatment and suggest an alternative medication. However, don't stop taking it unless you've been advised to by a healthcare professional.
As nephrogenic diabetes insipidus is caused by your kidneys not responding to AVP, rather than a shortage of AVP, it usually can't be treated with desmopressin. However, it's still important to drink plenty of water to avoid dehydration.
If your condition is mild, your GP or endocrinologist may suggest reducing the amount of salt and protein in your diet, which will help your kidneys produce less urine. This may mean eating less salt and protein-rich food, such as processed foods, meat, eggs and nuts. Don't alter your diet without first seeking medical advice. Your GP or endocrinologist will be able to advise you about which foods to cut down on.
Read more about eating a healthy, balanced diet.
If you have more severe nephrogenic diabetes insipidus, you may be prescribed a combination of thiazide diuretics and an NSAID to help reduce the amount of urine your kidneys produce.
Thiazide diuretics can reduce the rate the kidney filters blood, which reduces the amount of urine passed from the body over time.
Side effects are uncommon but include:
This last side effect is usually temporary and should resolve itself if you stop taking the medication.
However, long-term use of NSAIDs increases your risk of developing a stomach ulcer. To counter this increased risk, an additional medication called a proton pump inhibitor (PPI) may be prescribed. PPIs help protect your stomach lining against the harmful effects of NSAIDs, reducing the risk of ulcers forming.
Read more about treating stomach ulcers.
The two main complications of diabetes insipidus are dehydration and an electrolyte imbalance. Complications are more likely if the condition goes undiagnosed or is poorly controlled.
If you have diabetes insipidus, your body will find it difficult to retain enough water, even if you drink fluid constantly. This can lead to dehydration (a severe lack of water in the body).
If you or someone you know has diabetes insipidus, it's important to look out for the signs and symptoms of dehydration. These may include:
Dehydration can be treated by rebalancing the level of water in your body.
If you're severely dehydrated, you may need intravenous fluid replacement in hospital. This is where fluids are given directly through a drip into your vein.
Read more about treating dehydration.
Diabetes insipidus can also cause an electrolyte imbalance. Electrolytes are minerals in your blood that have a tiny electric charge, such as sodium, calcium, potassium, chlorine, magnesium and bicarbonate.
If the body loses too much water, the concentration of these electrolytes can go up simply because the amount of water they're contained in has gone down.
This dehydration disrupts other functions of the body, such as the way muscles work. It can also lead to: