What Diabetes Insipidus Is and How It Differs from Type 1 and Type 2 Diabetes

Diabetes insipidus is a rare condition where your kidneys cannot hold onto water the way they should, so you urinate far more than normal and become very thirsty. Despite the name, it has nothing to do with blood sugar or insulin — it is a completely different disease from type 1 and type 2 diabetes. The word "diabetes" in both names is misleading; the only real connection is that both cause excessive thirst and urination.

In diabetes insipidus, your body either does not make enough of a hormone called antidiuretic hormone (ADH), or your kidneys do not respond to the ADH that is there. ADH tells your kidneys to hold onto water instead of flushing it out. When ADH is low or not working, you lose water constantly through urine, and your body tries to replace it by making you thirsty. If you drink enough water, you may feel fine. If you cannot drink enough — or if you lose track of how much you need — you can become dangerously dehydrated.

There are two main types. Central diabetes insipidus happens when your pituitary gland (a small gland at the base of your brain) does not make enough ADH. Nephrogenic diabetes insipidus happens when your kidneys work fine but do not respond to the ADH your body makes. A third, much rarer type called gestational diabetes insipidus can occur during pregnancy and usually goes away after birth.

Key Takeaways

  • Diabetes insipidus causes extreme thirst and very frequent urination because your body cannot hold onto water the way it should.
  • The two main types are central (your pituitary gland does not make enough ADH) and nephrogenic (your kidneys do not respond to ADH).
  • Symptoms can develop suddenly or slowly, and a blood test and urine test are the main ways doctors confirm the diagnosis.
  • Treatment depends on the type: central diabetes insipidus is usually treated with a synthetic ADH medication, while nephrogenic diabetes insipidus requires a different approach.
  • You should see a doctor if you have extreme thirst and urination that lasts more than a few days, or if these symptoms appear suddenly.

What Causes Diabetes Insipidus

Central diabetes insipidus can be caused by head injury, brain surgery, a tumor in or near the pituitary gland, infection, stroke, or bleeding in the brain. Sometimes the cause is never found. In some families, a genetic mutation causes the pituitary gland to fail to make ADH from birth or early childhood.

Nephrogenic diabetes insipidus can run in families as a genetic condition, but it can also develop later in life. Certain medications — most commonly lithium, used to treat bipolar disorder — can damage the kidneys' ability to respond to ADH. Chronic kidney disease, high calcium levels in the blood, and severe dehydration can also cause it. In some cases, the cause is unknown.

Gestational diabetes insipidus is thought to happen because pregnancy changes how quickly the body breaks down ADH. It is not related to gestational diabetes (high blood sugar during pregnancy) and does not mean you will develop diabetes insipidus after pregnancy, though some women do.

Symptoms to Watch For

The hallmark symptoms are extreme thirst and urination much more often than normal — sometimes 15 to 20 times a day or even more. You may wake up many times at night to urinate. Urine is usually very pale or clear because it is mostly water. Some people describe the thirst as unquenchable, even right after drinking.

If you cannot drink enough water — for example, if you are unconscious, very young, or unable to access water — you can become dehydrated quickly. Signs of dehydration include dry mouth and skin, weakness, dizziness, confusion, and a rapid heartbeat. In severe cases, dehydration can cause seizures or loss of consciousness.

Symptoms can start suddenly or develop slowly over weeks or months. In children, parents may notice the child wets the bed after being dry at night, or drinks and urinates much more than siblings the same age. In older adults, the symptoms are sometimes mistaken for a urinary tract infection or blamed on aging.

How Doctors Diagnose Diabetes Insipidus

Your doctor will start by asking about your thirst and urination patterns, when they started, and whether anything triggered them. They will also ask about medications you take, any head injuries or brain surgery, and whether anyone in your family has diabetes insipidus.

The main tests are a blood test and a 24-hour urine test. The blood test measures the level of sodium and the concentration of ADH in your blood. The urine test measures how much urine you produce in 24 hours and how dilute it is. In diabetes insipidus, urine is very dilute (mostly water) even though blood sodium is high, which is the opposite of what happens in healthy people.

If the first tests suggest diabetes insipidus, your doctor may do a water deprivation test. You stop drinking water for several hours while doctors measure blood sodium and urine output. If you have central diabetes insipidus, your symptoms improve when you are given synthetic ADH. If you have nephrogenic diabetes insipidus, synthetic ADH does not help. This test tells your doctor which type you have, which matters because treatment is different.

Your doctor may also order an MRI of your brain to look for a tumor, injury, or other problem with the pituitary gland, especially if you have central diabetes insipidus.

Treatment for Central Diabetes Insipidus

Central diabetes insipidus is usually treated with a synthetic ADH medication called desmopressin (brand names include DDAVP and Stimate). Desmopressin replaces the ADH your body is not making. It comes as a nasal spray, a tablet you swallow, an injection, or a melt that dissolves under your tongue. Your doctor will help you find the dose and timing that works best for you.

Most people take desmopressin once or twice a day, though some need it more often. You will need to learn how much water to drink — too little and you become dehydrated, too much and your blood sodium drops too low, which can cause confusion, seizures, or coma. Your doctor will give you specific guidance based on your dose and your individual needs.

If your central diabetes insipidus was caused by a tumor or injury, treating that underlying problem may restore your body's ability to make ADH. If the cause cannot be fixed, you will take desmopressin long-term. Your doctor will check your blood sodium levels regularly to make sure your dose is right.

Treatment for Nephrogenic Diabetes Insipidus

Nephrogenic diabetes insipidus does not respond to desmopressin because the problem is in the kidneys, not the pituitary gland. Treatment focuses on reducing how much urine your body makes and preventing dehydration.

A low-sodium diet helps because it reduces the amount of water your kidneys need to flush out. Drinking enough water to match what you lose is essential — your doctor will tell you how much that is for you. Some people need to drink 3 to 4 liters a day or more. Staying cool and avoiding heat and exercise that causes heavy sweating also helps, because sweating reduces how much water you lose through urine.

Certain medications can help. Thiazide diuretics (water pills) may seem counterintuitive, but they can reduce urine output in nephrogenic diabetes insipidus. Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen can also help, though they are not used long-term because of side effects. If you take lithium and have developed nephrogenic diabetes insipidus, your doctor may switch you to a different medication for bipolar disorder.

When to See a Doctor and What to Ask

See a doctor if you have extreme thirst and urination that lasts more than a few days, if these symptoms appear suddenly, or if you wake up many times at night to urinate and it is affecting your sleep or daily life. If you become confused, very weak, or have a rapid heartbeat along with extreme thirst, seek care right away — these can be signs of dangerous dehydration.

If you have already been diagnosed with diabetes insipidus, contact your doctor if your symptoms change, if you cannot keep up with your thirst even when drinking constantly, if you feel confused or very weak, or if you are having side effects from your medication.

Questions to ask your doctor include: "What type of diabetes insipidus do I have, and what caused it?" "How much water should I drink each day?" "What are the signs that I am not drinking enough?" "How often will you check my blood sodium levels?" "Are there foods or activities I should avoid?" "What should I do if I cannot take my medication for a day?" and "Could any of my other medications be making this worse?"

Frequently Asked Questions

Is diabetes insipidus the same as type 1 or type 2 diabetes?

No. Type 1 and type 2 diabetes affect blood sugar and involve the pancreas and insulin. Diabetes insipidus affects how your kidneys handle water and involves a hormone called ADH. They are completely different diseases that happen to have similar names because both cause thirst and frequent urination.

Can diabetes insipidus go away on its own?

It depends on the cause. If diabetes insipidus was caused by a temporary condition like a head injury or infection, it may improve as you heal. Gestational diabetes insipidus usually goes away after pregnancy. But if it is caused by a genetic condition or permanent damage to the pituitary gland or kidneys, it will not go away and requires long-term treatment.

What happens if I do not drink enough water?

You become dehydrated, which can cause weakness, dizziness, confusion, and a rapid heartbeat. Severe dehydration can lead to seizures, loss of consciousness, or organ damage. This is why staying aware of your thirst and drinking enough water is so important.

Can I take desmopressin if I have nephrogenic diabetes insipidus?

No. Desmopressin only works if your kidneys can respond to ADH. In nephrogenic diabetes insipidus, the kidneys cannot respond, so desmopressin will not help. Your doctor will recommend a different treatment plan focused on diet, water intake, and other medications.

Will I need to take medication forever?

If your diabetes insipidus was caused by something that can be fixed — like a tumor that is removed or an infection that clears up — you may not need medication long-term. But if the cause is permanent, such as a genetic condition or irreversible damage to the pituitary gland or kidneys, you will likely need treatment for life. Your doctor can tell you what to expect based on your specific situation.