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Hyperosmolar Hyperglycemic State (HHS)

(Nonketotic Hyperosmolar Syndrome; Nonketotic Hyperosmolar Coma)


Erika F. Brutsaert

, MD, New York Medical College

Reviewed/Revised Oct 2023

Hyperosmolar hyperglycemic state is a complication of diabetes mellitus that most often occurs in type 2 diabetes.

  • Symptoms of hyperosmolar hyperglycemic state include extreme dehydration and confusion.

  • Hyperosmolar hyperglycemic state is diagnosed by blood tests that show very high levels of glucose, sodium, and other substances.

  • Treatment is intravenous fluids and insulin.

  • Complications include coma, seizures, and death.

There are two types of diabetes mellitus, type 1 and type 2. In type 1 diabetes, the body produces almost no insulin, a hormone produced by the pancreas that helps sugar (glucose) move from the blood into the cells. In type 2 diabetes, the body produces insulin, but cells fail to respond normally to the insulin. In both types of diabetes, the amount of sugar (glucose) in the blood is elevated.

If people with type 1 diabetes receive no insulin, or they need more insulin because of an illness, fat cells begin breaking down to provide energy. Fat cells that break down produce substances called ketones. Ketones provide some energy to cells but also make the blood too acidic (ketoacidosis). Diabetic ketoacidosis Diabetic Ketoacidosis Diabetic ketoacidosis is an acute complication of diabetes that occurs mostly in type 1 diabetes mellitus. Symptoms of diabetic ketoacidosis include nausea, vomiting, abdominal pain, and a characteristic... read more is a dangerous, sometimes life-threatening, disorder.

Because people with type 2 diabetes produce some insulin, ketoacidosis does not usually develop even when type 2 diabetes is untreated for a long time. However, with hyperosmolar hyperglycemic state, the blood glucose levels can become extremely high (even exceeding 1,000 milligrams per deciliter [mg/dL], or 55.5 millimoles per liter [mmol/L] of blood). Such very high blood glucose levels cause the person to pass large amounts of urine, which eventually causes severe dehydration Dehydration Dehydration is a deficiency of water in the body. Vomiting, diarrhea, excessive sweating, burns, kidney failure, and use of diuretics may cause dehydration. People feel thirsty, and as dehydration... read more . Blood levels of sodium and other substances also rise, making the person's blood abnormally concentrated (hyperosmolar). Thus, the disorder is called hyperosmolar hyperglycemic state.

Causes of Hyperosmolar Hyperglycemic State

Hyperosmolar hyperglycemic state can occur for two main reasons

  • People stop taking the medications for their diabetes

  • An infection or other illness stresses the body

Also, certain medications, such as corticosteroids, can raise blood glucose levels and cause hyperosmolar hyperglycemic state. Medications such as diuretics Diuretics Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more , which people often take to treat high blood pressure, can worsen dehydration and trigger hyperosmolar hyperglycemic state.

Symptoms of Hyperosmolar Hyperglycemic State

The main symptom of hyperosmolar hyperglycemic state is a mental change. The change ranges from mild confusion and disorientation to drowsiness and coma. Some people have seizures and/or temporary partial paralysis resembling a stroke. Up to 20% of people die. Other symptoms that may precede the change in mental state include frequent urination and extreme thirst.

Diagnosis of Hyperosmolar Hyperglycemic State

  • Blood tests to measure glucose level

Doctors suspect the diagnosis of hyperosmolar hyperglycemic state when people who have recently developed confusion are found to have a very high blood glucose level. They confirm the diagnosis by doing additional blood tests that show very concentrated blood and low ketones or acidity in the bloodstream.

Treatment of Hyperosmolar Hyperglycemic State

  • Fluids and electrolytes given by vein

  • Insulin given by vein

Hyperosmolar hyperglycemic state is treated much like diabetic ketoacidosis Treatment Diabetic ketoacidosis is an acute complication of diabetes that occurs mostly in type 1 diabetes mellitus. Symptoms of diabetic ketoacidosis include nausea, vomiting, abdominal pain, and a characteristic... read more . Fluids and electrolytes must be replaced intravenously. Usually, people are given insulin intravenously so that it works quickly and the dose can be adjusted frequently. The level of glucose in the blood must be restored to normal gradually to avoid sudden shifts of fluid within the brain. The blood glucose level tends to be more easily controlled than in diabetic ketoacidosis, and blood acidity problems are not severe.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Afrezza, Exubera
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