Definition of Diabetic hyperglycemic hyperosmolar coma:

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

Causes, incidence, and risk factors:

Diabetic hyperglycemic hyperosmolar coma is a condition of decreased consciousness, extreme dehydration (lack of water), and extremely high blood glucose (sugar) levels, which is not accompanied by ketoacidosis.

The condition is usually seen in people with non-insulin-dependent diabetes (type 2 diabetes). It may occur in those previously undiagnosed with diabetes, or in people who have not been able to control their diabetes with diet and medications. The condition may be brought on by an infection, or by certain medications that lower glucose tolerance or increase fluid loss.

Normally, the kidneys make up for high glucose levels in the blood by allowing the extra glucose to leave the body in the urine. However, when water is scarce, the kidneys conserve (save) fluid, and glucose levels become higher. This results in greater need for water.

Hyperosmolarity is a condition in which the blood has a high concentration of sodium, glucose, and other molecules that normally attract water into the bloodstream. When the kidneys are conserving water, however, this creates a vicious cycle of increasing blood-glucose levels and increasing dehydration.

Risk factors include:

• Older age
• Underlying kidney insufficiency (the kidneys do not work well)
• Congestive heart failure
• Stopping insulin or other medications that lower glucose levels
• Improper management of diabetes -- not following the treatment plan as directed
• A stressful event such as infection, heart attack, stroke, or recent surgery