Diabetes insipidus Mate huka mimi waimeha

Your body produces a hormone called anti-diuretic hormone (ADH). This hormone works on your kidneys to control how much wee (urine) you make. ADH is also called arginine vasopressin (AVP) and is made in a part of your brain called the hypothalamus. It is then stored in the pea-sized pituitary gland, which sits below your brain behind your nose.

There are 2 types of diabetes insipidus.

• Cranial diabetes insipidus is when the cause is in your brain.
• Nephrogenic diabetes insipidus is when the problem is in your kidneys.

Cranial diabetes insipidus happens if your body does not make enough ADH. The most common causes of this are:

• a brain tumour damaging your hypothalamus or pituitary
• a severe head injury
• damage caused by brain surgery.

Nephrogenic diabetes insipidus happens if you have enough ADH but your kidneys do not respond to it. This means your kidneys do not save enough water, so you pass lots of urine. It can be hereditary (passed down in families). Other causes of this include:

• a side effect of lithium medication (it happens to 20 to 40% of people taking lithium)
• chronic kidney damage or a kidney infection
• high blood calcium.

The symptoms of diabetes insipidus include:

• being very thirsty and particularly wanting to drink cold water
• passing a lot of pale wee (up to 6 times as much as normal).

Pēpi and young tamariki can get diabetes insipidus and their symptoms may also include:

• losing weight
• irritability
• poor growth
• headaches
• hard poos (constipation).

Diabetes insipidus is not usually dangerous but there are some possible complications to look out for and manage, including:

• dehydration
• electrolyte imbalance (too much or not enough of certain minerals in your body.

These can lead to seizures and possible brain damage if not treated quickly.

To diagnose diabetes insipidus, you will need to have blood and urine tests. You may need to stop drinking any fluid for a time to check if your urine becomes concentrated.

Your healthcare provider may also give you a dose of ADH to see how your kidneys respond.

You might also need an MRI scan of the pituitary region of your brain.

It is important to drink plenty of fluid to prevent dehydration. Aim for at least 10 cups of fluids a day. Always have water or other fluids with you when you are away from home. 

If you have nephrogenic diabetes insipidus, your healthcare provider may advise you to have less salt and protein-rich food such as meat, eggs and dairy products. This can help your kidneys produce less wee (urine).

Cranial diabetes insipidus

Cranial diabetes insipidus is treated with artificial ADH called desmopressin. It is likely you will be on this treatment for the rest of your life. The underlying cause of your diabetes insipidus may also need to be treated. 

You usually take desmopressin as a nasal spray. Sometimes your health professional will prescribe desmopressin as a tablet. The amount of desmopressin you need varies between different people and can change over time.

If you do not take enough desmopressin, you will get thirsty again and need to pass a lot of wee.

If you take too much desmopressin, your body keeps too much water. This causes your blood sodium to go low. It may make you feel unwell, and you might feel sick and have headaches. Severe low sodium can cause confusion.

To prevent this, your healthcare provider may ask you to pause taking your desmopressin until you start passing a lot of wee. They may suggest you do this once a week for example. This is to give your body a chance to get rid of any excess water that it may have built up. After this happens, you can take your usual dose. 

Taking other medications can affect your sodium levels and the amount of desmopressin you need. Check with your healthcare provider when starting new medications. You may need to adjust your medication if you:

• become unwell and throw up (vomit) or get runny poos (diarrhoea)
• have to have surgery.

Nephrogenic diabetes isipidus

Nephrogenic diabetes is harder to treat as ADH does not help. Your healthcare provider may suggest stopping any medications that could be causing the problem (such as lithium). But you should not stop taking any medications without your healthcare provider's advice.