The result of diabetic coma from having either extremely high or tremendously low blood sugar levels. A person with extremely high levels is hyperglycemic, and a person with extremely low levels is hypoglycemic. If treated quickly, a person will make a rapid recovery from a diabetic coma. However, a diabetic coma can be deadly or result in brain damage. The severe symptoms of uncontrolled blood sugar that can come before a diabetic coma include vomiting, difficulty breathing, confusion, weakness, and dizziness.