Hyperosmolar Nonketotic Coma
(HHNC; Hyperosmolar Coma; Diabetic Nonketotic Coma; Hyperosmolar Nonketotic State)
by Krisha McCoy, MS
Hyperosmolar nonketotic coma occurs in people with diabetes. 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. Low levels of these substances can lead to seizures, coma, and eventually death.
Risk Factors TOP
The chance of hyperosmolar nonketotic coma is higher in older adults.
Other factors that may increase your chance of hyperosmolar nonketotic coma include having diabetes and:
Symptoms that may occur before the hyperosmolar nonketotic coma may include:
If you arrive at the hospital in a hyperosmolar nonketotic coma, your vital signs will be monitored. The levels of glucose and other substances in your blood will be tested with:
An EKG may also be done to check your heart's electrical activity.
You will likely need treatment in the emergency room and/or the intensive care unit at the hospital. Treatment will focus on restoring the correct balance of substances in your blood, including glucose. Treatment may include:
You may need additional treatment, such as antibiotics, if an infection led to the coma.
To help prevent hyperosmolar nonketotic coma:
American Diabetes Association
National Diabetes Information Clearinghouse
Canadian Diabetes Association
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Updated January 12, 2014. Accessed September 30, 2014.
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Hyperosmolar hyperglycemic nonketotic syndrome (HHNS). American Diabetes Association website. Available at:
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Updated December 6, 2014. Accessed September 30, 2014.
Last reviewed August 2014 by Kim Carmichael, MD
Last Updated: 9/30/2014
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