Health Encyclopedia

Diabetic hyperglycemic hyperosmolar syndrome

Definition

Diabetic hyperglycemic hyperosmolar syndrome (HHS) is a complication of type 2 diabetes. It involves extremely high blood sugar (glucose) level without the presence of ketones.

Alternative Names

HHS; Hyperglycemic hyperosmolar coma; Nonketotic hyperglycemic hyperosmolar coma (NKHHC); Hyperosmolar nonketotic coma (HONK); Hyperglycemic hyperosmolar non-ketotic state; Diabetes - hyperosmolar

Causes

HHS is a condition of:

Extremely high blood sugar (glucose) level
Extreme lack of water (dehydration)
Decreased alertness or consciousness (in many cases)

Buildup of ketones in the body (ketoacidosis) may also occur. But it is unusual and is often mild compared with diabetic ketoacidosis.

HHS is more often seen in people with type 2 diabetes who don't have their diabetes under control. It may also occur in those who have not been diagnosed with diabetes. The condition may be brought on by:

Infection
Other illness, such as heart attack or stroke
Medicines that decrease the effect of insulin in the body
Medicines or conditions that increase fluid loss
Running out of, or not taking prescribed diabetes medicines

Normally, the kidneys try to make up for a high glucose level in the blood by allowing the extra glucose to leave the body in the urine. But this also causes the body to lose water. If you do not drink enough water, or you drink fluids that contain sugar and keep eating foods with carbohydrates, you become very dehydrated. When this occurs, the kidneys are no longer able to get rid of the extra glucose. As a result, the glucose level in your blood can become very high, sometimes more than 10 times the normal amount.

The loss of water also makes the blood more concentrated than normal. This is called hyperosmolarity. It is a condition in which the blood has a high concentration of salt (sodium), glucose, and other substances. This draws the water out of the body's other organs, including the brain.

Risk factors include:

A stressful event such as infection, heart attack, stroke, or recent surgery
Heart failure
Impaired thirst
Limited access to water (especially in people with dementia or who are bedbound)
Older age
Poor kidney function
Poor management of diabetes, not following the treatment plan as directed
Stopping or running out of insulin or other medicines that lower glucose level

Symptoms

Symptoms may include any of the following:

Increased thirst and urination (at the beginning of the syndrome)
Feeling weak
Nausea
Weight loss
Dry mouth, dry tongue
Fever
Seizures
Confusion
Coma

Symptoms may get worse over days or weeks.

Other symptoms that may occur with this disease:

Loss of feeling or function of muscles
Problems with movement
Speech impairment

Exams and Tests

The health care provider will examine you and ask about your symptoms and medical history. The exam may show that you have:

Extreme dehydration
Fever higher than 100.4°F (38°C)
Increased heart rate
Low systolic blood pressure

Test that may be done include:

Blood osmolarity (concentration)
BUN and creatinine levels
Blood sodium level (needs to be adjusted for the blood glucose level)
Ketone test
Blood glucose, potassium, and bicarbonate

Evaluation for possible causes may include:

Blood and urine cultures
Chest x-ray
Electrocardiogram (ECG)
Urinalysis
Covid-19 and influenza testing
CT of the head

Treatment

At the start of treatment, the goal is to correct the water loss. This will improve the blood pressure, urine output, and circulation. Blood sugar will also decrease.

Fluids and potassium will be given through a vein (intravenously). This must be done carefully. High glucose level is treated with insulin given through a vein.

Outlook (Prognosis)

People who develop HHS are often already ill. If not treated right away, seizures, coma, or death may result.

Possible Complications

Untreated, HHS may lead to any of the following:

Shock
Blood clot formation
Brain swelling (cerebral edema)
Increased blood acid level (lactic acidosis)

When to Contact a Medical Professional

This condition is a medical emergency. Go to the emergency room or call the local emergency number (such as 911) if you develop symptoms of HHS.

Prevention

Controlling type 2 diabetes and recognizing the early signs of dehydration and infection can help prevent HHS. Have a "sick-day plan" so you will be prepared for days when you are not going to be eating well. Also try to order your diabetes and other medicines in 3-month amounts so you will be less likely to run out of them.

References

Crandall JP, Shamoon H. Diabetes mellitus. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 216.

Lebovitz HE. Hyperglycemia secondary to nondiabetic conditions and therapies. In: Jameson JL, De Groot LJ, de Kretser DM, et al, eds. Endocrinology: Adult and Pediatric. 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 42.

Sinha A. Diabetic emergencies. In: Bersten AD, Handy JM, eds. Oh's Intensive Care Manual. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 59.

Review Date:1/9/2022
Reviewed By:Robert Hurd, MD, Professor of Endocrinology and Health Care Ethics, Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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