Diabetic hyperglycemic hyperosmolar syndrome is a condition of:
-- Extremely high blood sugar (glucose) level
-- Extreme lack of water (dehydration)
-- Decreased consciousness (in many cases)

This condition is usually 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
-- Medicines or conditions that increase fluid loss
-- Other illness, such as heart attack or stroke
-- Medicines that decrease the effect of insulin in the body

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, the kidneys can no longer get rid of the extra glucose. As a result, the glucose level in your blood can become very high.

The loss of water (dehydration) 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 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:
-- 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
-- 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)