DefinitionDiabetic 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.Alternative NamesHyperglycemic hyperosmolar coma; Nonketotic hyperglycemic hyperosmolar coma (NKHHC); Hyperosmolar nonketotic coma (HONK)Causes, incidence, and risk factorsDiabetic hyperglycemic hyperosmolar syndrome is a condition of:Extremely high blood sugar (glucose) levelsExtreme lack of water (dehydration)Decreased consciousnessThe 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 con