by McCoy K
(HHS; Hyperosmolar Nonketotic Coma; HHNC)


Hyperosmolar hyperglycemic state (HHS) is when a person with diabetes has very high blood glucose levels and loses too much fluid. People with HHS may lose consciousness and go into a coma. It can be deadly without treatment.


HHS happens when there is too much glucose in the blood. The body tries to fix this by passing extra glucose out in the urine. If too much water is passed out of the body as urine, it can be hard for the heart and brain to work.

It can be triggered by:

  • Infection
  • Poorly controlled diabetes
  • Illnesses, such as pancreatitis
  • Heart attack or Stroke
  • Trauma
  • Kidney failure
  • Certain medicines, such as diuretics and steroids
  • Recent surgery
  • Risk Factors

    HHS can happen at any age. It is more common in older adults and people with type 2 diabetes.


    Common symtoms are:

    • Dry mouth and severe thirst
    • Urinating (peeing) often
    • Confusion
    • Seizures
    • Sleepiness
    • Changes in vision
    • Seeing or hearing things that are not there
    • Weakness


    The doctor will ask about your symptoms and health history. A physical exam will be done.

    Blood tests will be done to measure blood glucose levels and check for signs of infection. Urine tests will be done to find out if your body is burning fat for energy. This may happen when there is not enough glucose in the body. Urine tests can also check for signs of infection.

    The heart may also be checked. An EKG can check your heart's electrical activity.

    nucleus image
    Copyright © Nucleus Medical Media, Inc.


    Emergency medical care will be needed. The goal of treatment is put the fluids and minerals a person has lost back into their body to make them feel better. Glucose will also be put back to the right level. This can be done through IV.

    Other treatment may be needed if there is an infection.


    The risk of this health problem can be lowered by:

    • Following your diabetes care plan
    • Eating a healthful diet and drinking plenty of fluids
    • Seeking care for illnesses or signs of infection


    American Diabetes Association 

    National Institute of Diabetes and Digestive and Kidney Diseases 


    Canadian Diabetes Association 

    Health Canada 


    Hyperglycemic hyperosmolar state in adults. EBSCO DynaMed website. Available at:  . Accessed February 18, 2022.

    Hyperglycemic hyperosmolar state in children. EBSCO DynaMed website. Available at:  . Accessed February 18, 2022.

    Stoner, G. Hyperosmolar hyperglycemic state. American Family Physician, 2017; 96(11): 729-736. Available at: . Accessed February 18, 2022.

    Revision Information