Diabetic coma is a reversible form of coma found in people with diabetes mellitus. It is a medical emergency.Three different types of diabetic coma are identified:
Severe low blood sugar in a diabetic person
Diabetic ketoacidosis (usually type 1) advanced enough to result in unconsciousness from a combination of a severely increased blood sugar level, dehydration and shock, and exhaustion
Hyperosmolar nonketotic coma (usually type 2) in which an extremely high blood sugar level and dehydration alone are sufficient to cause unconsciousness.In most medical contexts, the term diabetic coma refers to the diagnostical dilemma posed when a physician is confronted with an unconscious patient about whom nothing is known except that they have diabetes. [Source: Wikipedia 
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