Diabetic hyperglycemic hyperosmolar syndrome (HHS) is a complication of type 2 diabetes that involves extremely high blood sugar (glucose) levels without the presence of ketones. Ketones are byproducts of fat breakdown.

Diabetic hyperglycemic hyperosmolar syndrome is a condition of:

• Extremely high blood sugar (glucose) levels
• Extreme lack of water (dehydration)
• Decreased consciousness

The buildup of ketones in the body (ketoacidosis) may also occur.

This condition is usually seen in people with type 2 diabetes. It may occur in those who have not been diagnosed with diabetes, or in people who have not been able to control their diabetes. The condition may be brought on by:

• Infection
• Other illness
• Medications that lower glucose tolerance or increase fluid loss (in people who are losing or not getting enough fluid)

Normally, the kidneys try to make up for high glucose levels in the blood by allowing the extra glucose to leave the body in the urine. If you do not drink enough fluids, or you drink fluids that contain sugar, the kidneys can no longer get rid of the extra glucose. Glucose levels in the blood can become very high as a result. The blood then becomes much more concentrated than normal (hyperosmolarity).

Hyperosmolarity is a condition in which the blood has a high concentration of salt (sodium), glucose, and other substances that normally cause water to move into the bloodstream. This draws the water out of the body's other organs, including the brain. Hyperosmolarity creates a cycle of increasing blood-glucose levels and dehydration.

Risk factors include:

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