Hyperglycemia is having very high blood sugar levels. This occurs when the body does not have or use enough insulin, the hormone responsible for lowering sugar in the blood. Hyperglycemia is the primary indicator of diabetes (hyperlink). The symptoms include frequent urination, feeling thirsty more often, headache, blurred vision, above average glucose levels in urine, and having blood glucose levels higher than 130 milligrams per deciliter. Treatments include diet moderation, exercise, and insulin medications.