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Diabetes insipidus vs. diabetes mellitus
Key takeaways
- Diabetes insipidus and diabetes mellitus share a name and symptoms (thirst, frequent urination) but are unrelated.
- In diabetes insipidus, blood sugar is normal; the problem is the hormone vasopressin (ADH) or the kidneys' response to it.
- People with diabetes insipidus can pass up to about 20 quarts of light-colored urine a day (NIDDK).
- Experts have proposed new names: arginine vasopressin deficiency (AVP-D) and resistance (AVP-R).
The key difference
| Diabetes insipidus | Diabetes mellitus | |
|---|---|---|
| Problem | Too little vasopressin, or kidneys don't respond to it | Too little insulin, or the body can't use it |
| Blood sugar | Normal | High |
| Urine | Very large amounts, dilute and light-colored, no sugar | More frequent; may contain sugar |
| How common | Rare | Very common (about 12% of the US population) |
| Treatment | Depends on type, e.g., desmopressin for central DI | Lifestyle, glucose-lowering medicines, insulin |
Why the shared name?
"Diabetes" comes from a Greek word for passing through — both conditions cause heavy urination. Historically, doctors tasted urine: in diabetes mellitus it was sweet ("honeyed"); in diabetes insipidus it was tasteless ("insipid"). Because the shared name causes confusion — and even dangerous mix-ups in hospitals — an international working group proposed in 2022 renaming central diabetes insipidus arginine vasopressin deficiency (AVP-D) and nephrogenic diabetes insipidus arginine vasopressin resistance (AVP-R).
Types of diabetes insipidus
- Central (AVP deficiency): the brain makes too little vasopressin — after head injury, surgery, tumors, or unknown causes.
- Nephrogenic (AVP resistance): the kidneys don't respond to vasopressin — inherited, or due to medicines such as lithium, or kidney problems.
- Dipsogenic: a problem with the thirst mechanism leads to drinking too much fluid.
- Gestational: temporary, during pregnancy.
Symptoms of diabetes insipidus
- Passing large amounts of light-colored urine, day and night
- Intense thirst, often craving cold water
- Waking up at night to urinate; bed-wetting in children
- Signs of dehydration if fluids can't keep up — dizziness, confusion, weakness
Most adults pass about 1–3 quarts of urine a day. If you're passing far more and are constantly thirsty, see a doctor. Severe dehydration or confusion is an emergency — call 911.
How doctors tell them apart
A blood glucose or A1C test shows whether sugar is high (diabetes mellitus). For diabetes insipidus, doctors check urine concentration, blood sodium, and may do a water deprivation or copeptin test.
Learn more about the common kind: what is diabetes mellitus?
This guide is general wellness education based on the public sources below. It is not medical advice, diagnosis, or treatment. Cardivo is not a medical device. If you think you are having a medical emergency, call 911.
Frequently asked questions
Is diabetes insipidus the same as diabetes?
No. Diabetes insipidus is a rare condition involving the hormone vasopressin or the kidneys; blood sugar is normal. Everyday 'diabetes' is diabetes mellitus, where blood sugar is high.
What is the new name for diabetes insipidus?
In 2022 an international working group proposed arginine vasopressin deficiency (AVP-D) for central diabetes insipidus and arginine vasopressin resistance (AVP-R) for nephrogenic diabetes insipidus.
What are the symptoms of diabetes insipidus?
Passing very large amounts of light-colored urine, intense thirst, and waking at night to urinate. Dehydration can occur if fluid intake doesn't keep up.
Sources
- NIDDK — Diabetes insipidus
- Working Group to Consider Renaming Diabetes Insipidus (2022) — Changing the name of diabetes insipidus: a position statement
- NIDDK — What is diabetes?