Coma may be due to a variety of causes not directly related to diabetes. Diabetic coma is a state of unconsciousness that can put a patient at risk of brain damage or even death. It is triggered by either persistent and extreme elevations in glucose (blood sugar) levels (hyperglycemia) or abnormally low glucose levels (hypoglycemia).
If the glucose level is too low, the person has hypoglycemia and if the level is too high, the person has hyperglycemia. Hyperglycemia is just a term for raised blood glucose but in some cases it can lead to a life-theathening condition called diabetic ketoacidosis. Patients with diabetes mellitus type 1 are especially prone to this condition.