• Hyperosmolar Nonketotic Coma

    (HHNC; Hyperosmolar Coma; Diabetic Nonketotic Coma; Hyperosmolar Nonketotic State)


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


    Hyperosmolar nonketotic coma is a complication of hyperosmolar hyperglycemic nonketotic syndrome (HHNS). HHNS happens when blood glucose levels rise, often with an illness or infection. Your body trys to get rid of excess blood glucose by passing it through your urine. It also washes out other substances that your body and brain need to function. 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:
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    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 or strange movements on one side of the body with or without seizures
    • Frequent urination


    If you arrive at the hospital in a hyperosmolar nonketotic coma, your vital signs will be monitored and you may receive the following tests:
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    You will likely need treatment in the emergency room and/or the intensive care unit at the hospital. 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 IV. It will replace substance you lost and improve your urine output.


    Insulin will be given through an IV. It will help control your blood glucose levels.

    Treatment for Underlying Cause

    Antibiotics may be given if an infection is suspected.


    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 doctor about how to manage your blood glucose when you are sick.


    American Diabetes Association http://www.diabetes.org/

    National Diabetes Information Clearinghouse http://diabetes.niddk.nih.gov/


    Canadian Diabetes Association http://www.diabetes.ca/

    Health Canada http://www.hc-sc.gc.ca/


    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 . Updated August 2, 2012. Accessed December 31, 2012.

    Kim DW, Moon Y, Gee Noh H, Choi JW, Oh J. Blood-brain barrier disruption is involved in seizure and hemianopsia in nonketotic hyperglycemia. Neurologist . 2011 May;17(3):164-166.

    Kitabchi AE. Hyperglycemic crises in diabetes mellitus: diabetic ketoacidosis and hyperglycemic hyperosmolar state. Endocrinol Metab Clin North Am . 2006;35:725-51

    Ondo WG. Hyperglycemic nonketotic states and other metabolic imbalances. Handb Clin Neurol . 2011;100:287-291.

    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 December 31, 2012.

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