Diabetes insipidus

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.

As the symptoms of diabetes insipidus are similar to those of other conditions, including type 1 diabetes and type 2 diabetes, tests will be needed to confirm which condition you have.

If diabetes insipidus is diagnosed, the tests will also be able to identify the type you have (cranial or nephrogenic).

Water deprivation test

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 pee large amounts of dilute urine when normally you'd only pee 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.

Vasopressin test

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 peeing urine, it's likely your condition is the result of a shortage of AVP.

If this is the case, you may be diagnosed with cranial diabetes insipidus.

If you continue to pee despite the dose of AVP, this suggests there's already enough AVP in your body, but your kidneys are not responding to it.

In this case, you may be diagnosed with nephrogenic diabetes insipidus.

MRI scan

An 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 caused by an abnormality in your hypothalamus or pituitary gland, it may need to be treated too, along with treatment for diabetes insipidus.

Treatment options depend on the type of diabetes insipidus you have.

Central diabetes insipidus. If you have mild diabetes insipidus, you may need only to increase your water intake. If the condition is caused by an abnormality in the pituitary gland or hypothalamus (such as a tumor), your doctor will first treat the abnormality.

Typically, this form is treated with a synthetic hormone called desmopressin (DDAVP, Nocdurna). This medication replaces the missing anti-diuretic hormone (ADH) and decreases urination. You can take desmopressin in a tablet, as a nasal spray or by injection.

Most people still make some ADH, though the amount can vary day to day. So, the amount of desmopressin you need also may vary. Taking more desmopressin than you need can cause water retention and potentially serious low-sodium levels in the blood.

Other medications might also be prescribed, such as chlorpropamide. This can make ADH more available in the body.

Nephrogenic diabetes insipidus. Since the kidneys don't properly respond to ADH in this form of diabetes insipidus, desmopressin won't help. Instead, your doctor may prescribe a low-salt diet to reduce the amount of urine your kidneys make. You'll also need to drink enough water to avoid dehydration.

Treatment with the drug hydrochlorothiazide (Microzide) may improve your symptoms. Although hydrochlorothiazide is a type of drug that usually increases urine output (diuretic), it can reduce urine output for some people with nephrogenic diabetes insipidus.

If your symptoms are due to medications you're taking, stopping these medicines may help. However, don't stop taking any medication without first talking to your doctor.

Gestational diabetes insipidus. Treatment for most people with gestational diabetes insipidus is with the synthetic hormone desmopressin.

Primary polydipsia. There is no specific treatment for this form of diabetes insipidus, other than decreasing fluid intake. If the condition is related to a mental illness, treating the mental illness may relieve the diabetes insipidus symptoms.