Hyperosmolar Nonketotic Coma
(HHNC; Hyperosmolar Coma; Diabetic Nonketotic Coma; Hyperosmolar Nonketotic State)
Definition
Hyperosmolar nonketotic coma occurs in people with diabetes . This condition is life-threatening, so it is important to seek medical attention immediately if you think you have any symptoms of an impending hyperosmolar nonketotic coma.
Causes
Hyperosmolar nonketotic coma is a complication of hyperosmolar hyperglycemic nonketotic syndrome (HHNS), in which your body tries to get rid of excess blood glucose by passing it through your urine. When HHNS is severe, it can lead to seizures , coma , and eventually death.
Risk Factors
The following factors are thought to increase the risk of hyperosmolar nonketotic coma:
- Older age
- Diabetes and poorly monitored glucose levels
- Infection
- Drugs (eg, diuretics, steroids, anticonvulsant, chemotherapy drugs)
- Disease states ( heart attack , stroke , kidney failure , overactive thyroid gland )
- Substance abuse
- Recent operation
Stroke

Symptoms
Symptoms that may occur before the onset of hyperosmolar nonketotic coma may include:
- High blood glucose (over 600 milligrams per deciliter)
- Dry mouth
- Thirst
- Warm, dry skin
- Absence of sweating
- Fever
- Leg cramps
- Sleepiness
- Confusion
- Vision loss
- Hallucinations
- Weakness on one side of the body
- Frequent urination
Diagnosis
If you arrive at the hospital in a hyperosmolar nonketotic coma, your vital signs will be monitored and you may receive the following tests:
- Blood tests—to test blood sugar, electrolytes, kidney function
- Chest x-ray —a test that uses radiation to take pictures of structures inside the body, especially bones
- Urine tests
- Electrocardiogram (ECG, EKG) —a test that records the heart’s activity by measuring electrical currents through the heart muscle
EKG

Treatment
Common treatments for hyperosmolar nonketotic coma include the following:
Fluid and Mineral Replacement
Fluids and minerals (potassium, sodium, chloride, phosphate, calcium, magnesium) will be given to you through an intravenous line to improve your urine output.
Insulin
To help control your blood glucose levels, you will receive insulin through an IV.
Treatment for Underlying Cause
If infection is the suspected cause, for example, then antibiotics will be administered.
Prevention
The best way to prevent hyperosmolar nonketotic coma is to monitor your blood glucose levels regularly. Your doctor can instruct you about how often to check your levels, and what the numbers mean. Also, talk with your healthcare provider about how to manage your blood glucose when you are sick.
RESOURCES:
American Diabetes Association
http://www.diabetes.org/
National Diabetes Information Clearinghouse
http://diabetes.niddk.nih.gov/
CANADIAN RESOURCES:
Canadian Diabetes Association
http://www.diabetes.ca/
Health Canada
http://www.hc-sc.gc.ca/index_e.html
References:
Chiasson JL, Aris-Jilwan N, Belanger R, et al. Diagnosis and treatment of diabetic ketoacidosis and the hyperglycemic hyperosmolar state. Can Med Assoc J. 2003;168:859-866.
Hyperosmolar hyperglycemic crisis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Accessed May 23, 2007.
Kitabchi AE. Hyperglycemic crises in diabetes mellitus: diabetic ketoacidosis and hyperglycemic hyperosmolar state. Endocrinol Metab Clin North Am. 2006;35:725-51
Stoner GD. Hyperosmolar hyperglycemic state. Am Fam Physician. 2005;71:1723-1730
What is hyperosmolar hyperglycemic nonketotic syndrome (HHNS)? American Diabetes Association website. Available at: http://www.diabetes.org/type-2-diabetes/treatment-conditions/hhns.jsp . Accessed May 23, 2007.
Last reviewed November 2008 by David Juan, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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