High blood glucose, elevated levels of sugar in the urine, frequent urination and increased thirst are symptoms of hyperglycemia, or high blood sugar, according to the American Diabetes Association. People with hyperglycemia either do not produce enough insulin, or their bodies do not process insulin properly.
Patients with diabetes may suffer from high blood sugar if they fail to give themselves enough insulin, or if they have enough insulin but their bodies do not process it properly, notes the American Diabetes Association. People may also suffer from high blood sugar if they overeat or do not get enough exercise. People with colds or the flu may also display high blood sugar, as can people suffering from mental stress such as family problems.
People who do not treat hyperglycemia may display the symptoms of ketoacidosis, or diabetic coma, notes the American Diabetes Association. Shortness of breath, breath that smells like fruit, nausea, vomiting and dry mouth are symptoms of ketoacidosis. Patients with high blood sugar can treat the condition by eating properly, exercising and checking regularly with their doctors to verify that they are taking the correct dosage of insulin or other medications. People suffering from high blood sugar who are diabetic should always carry or wear a medical identification to aid health care workers in treating them during an emergency.