Hyperosmolar Hyperglycemic Nonketotic Syndrome (HHNS)

Hyperosmolar Hyperglycemic Nonketotic Syndrome, or HHNS, is a serious condition most frequently seen in older persons. HHNS can happen to people with either type 1 or type 2 diabetes that is not being controlled properly, but it occurs more often in people with type 2. HHNS is usually brought on by something else, such as an illness or infection.

In HHNS, blood sugar levels rise, and your body tries to get rid of the excess sugar by passing it into your urine. You make lots of urine at first, and you have to go to the bathroom more often. Later you may not have to go to the bathroom as often, and your urine becomes very dark. Also, you may be very thirsty. Even if you are not thirsty, you need to drink liquids. If you don't drink enough liquids at this point, you can get dehydrated.

If HHNS continues, the severe dehydration will lead to seizures, coma and eventually death. HHNS may take days or even weeks to develop. Know the warning signs of HHNS.

What are the Warning Signs?

  • Blood sugar level over 600 mg/dl
  • Dry, parched mouth
  • Extreme thirst (although this may gradually disappear)
  • Warm, dry skin that does not sweat
  • High fever (over 101 degrees Fahrenheit, for example)
  • Sleepiness or confusion
  • Loss of vision
  • Hallucinations (seeing or hearing things that are not there)
  • Weakness on one side of the body

If you have any of these symptoms, call someone on your health care team.

How Can I Avoid It?

HHNS only occurs when diabetes is uncontrolled. The best way to avoid HHNS is to check your blood sugar regularly. Many people check their blood sugar several times a day, such as before or after meals. Talk with your health care team about when to check and what the numbers mean. You should also talk with your health care team about your target blood sugar range and when to call if your blood sugars are too high, or too low and not in your target range. When you are sick, you will check your blood sugar more often, and drink a glass of liquid (alcohol-free and caffeine-free) every hour. Work with your team to develop your own sick day plan.

Related Information

Another condition to watch signs for is ketoacidosis, which means dangerously high levels of ketones, or acids, that build up in the blood. Ketones appear in the urine when your body doesn't have enough insulin, and can poison the body.

  • Last Reviewed: August 21, 2013
  • Last Edited: December 6, 2013

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