Hyperosmolar Hyperglycemic State

(HHS; Hyperosmolar Nonketotic Coma; HHNC)


Hyperosmolar nonketotic coma occurs in people with diabetes, usually type 2. It is a life-threatening event. Seek medical attention right away if you think you have any symptoms of an impending hyperosmolar nonketotic coma.


Hyperosmolar nonketotic coma is a complication of very high blood glucose levels. Blood glucose often rises to these levels because of an illness or infection.

The body will try to get rid of the extra blood glucose through the urine. The frequency and volume of urination will increase. Unfortunately, this process also washes out other substances in your blood. Some of these substances are important to your brain and heart. Low levels of these substances can lead to seizures, arrhythmias, coma, and eventually death.

Risk Factors

Hyperosmolar nonketotic coma can happen at any age in patients with diabetes, but is most commonly see in older adults and patients with type 2 diabetes.

Other factors that may increase your chance of hyperosmolar nonketotic coma include:


Symptoms that may occur before the hyperosmolar nonketotic coma may include:

  • Dry mouth
  • Frequent urination
  • Thirst
  • Warm, dry skin without sweating
  • Nausea or vomiting
  • Mental confusion
  • Seizures
  • High fever
  • Sleepiness
  • Vision loss
  • Hallucinations
  • Weakness


If you arrive at the hospital in a hyperosmolar nonketotic coma, your vital signs will be monitored. Testing will be done with:

  • Blood tests
    • The levels of glucose and other substances in your blood will be tested
    • Tests for infection may also be done
  • Urine tests for glucose
  • Cultures if infection is suspected

An electrocardiogram (EKG) may also be done to check your heart's electrical activity.

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Treatment will be needed in the emergency room and/or the intensive care unit at the hospital. Treatment will focus on hydration and restoring the correct balance of substances in the blood, including glucose. Treatment may include:

  • Fluids and minerals through an IV
    • Improves hydration and replaces lost substances.
    • Will also help get rid of excess glucose in the urine
  • Insulin through an IV
    • Usually started right away in adults to control blood glucose levels.
    • Will be started in children after IV fluids have rehydrated them and some excess glucose has been voided

Additional treatment, such as antibiotics, may be needed if a bacterial infection is suspected.


To help prevent hyperosmolar nonketotic coma:

  • Monitor your blood glucose levels regularly. Your doctor can instruct you about how often to check your levels, and what the numbers mean.
  • Drink plenty of fluids throughout the day.
  • Talk with your doctor about how to manage your blood glucose when you are sick.

American Diabetes Association

National Institute of Diabetes and Digestive and Kidney Diseases


Canadian Diabetes Association

Health Canada


Hyperglycemic hyperosmolar state in adults. EBSCO DynaMed Plus website. Available at: Updated January 1, 2016. Accessed August 24, 2017.

Hyperglycemic hyperosmolar state in children. EBSCO DynaMed Plus website. Available at: Updated February 7, 2017. Accessed August 24, 2017.

Hyperosmolar hyperglycemic nonketotic syndrome (HHNS). American Diabetes Association website. Available at: Updated December 6, 2013. Accessed August 24, 2017.

Wolfsdorf J, et al. ISPAD Clinical Practice Consensus Guidelines 2014. Diabetic ketoacidosis and hyperglycemic hyperosmolar state. Pediatr Diabetes. 2014 Sep;15 Suppl 20:154-79.

Zeitler P, et al. Hyperglycemic hyperosmolar syndrome in children: pathophysiological considerations and suggested guidelines for treatment. J Pediatr. 2011 Jan;158(1):9-14.

Last reviewed September 2018 by EBSCO Medical Review Board Michael Woods, MD, FAAP  Last Updated: 8/24/2017