Hyperglycemia doesn't cause symptoms until glucose values are significantly elevated — above 200 milligrams per deciliter (mg/dL), or 11 millimoles per liter (mmol/L). Symptoms of hyperglycemia develop slowly over several days or weeks. The longer blood sugar levels stay high, the more serious the symptoms become. However, some people who've had type 2 diabetes for a long time may not show any symptoms despite elevated blood sugars.
Early signs and symptoms
Recognizing early symptoms of hyperglycemia can help you treat the condition promptly. Watch for:
- Frequent urination
- Increased thirst
- Blurred vision
Later signs and symptoms
If hyperglycemia goes untreated, it can cause toxic acids (ketones) to build up in your blood and urine (ketoacidosis). Signs and symptoms include:
- Fruity-smelling breath
- Nausea and vomiting
- Shortness of breath
- Dry mouth
- Abdominal pain
When to see a doctor
Call 911 or emergency medical assistance if:
- You're sick and can't keep any food or fluids down, and
- Your blood glucose levels are persistently above 240 mg/dL (13 mmol/L) and you have ketones in your urine
Make an appointment with your doctor if:
April 18, 2015
- You experience ongoing diarrhea or vomiting, but you're able to take some foods or drinks
- You have a fever that lasts more than 24 hours
- Your blood glucose is more than 240 mg/dL (13 mmol/L) even though you've taken your diabetes medication
- You have trouble keeping your blood glucose within the desired range
- Hyperglycemia (high blood glucose). American Diabetes Association. http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/hyperglycemia.html. Accessed March 24, 2015.
- Your guide to diabetes: Type 1 and type 2. National Institute of Diabetes and Digestive and Kidney Diseases. http://diabetes.niddk.nih.gov/dm/pubs/type1and2/index.aspx. Accessed March 24, 2015.
- McCulloch DK. Management of persistent hyperglycemia in type 2 diabetes mellitus. http://www.uptodate.com/home. Accessed March 24, 2015.
- Kitabchi AE, et al. Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Treatment. http://www.uptodate.com/home. Accessed March 24, 2015.
- Castro MR (expert opinion). Mayo Clinic, Rochester, Minn. March 24, 2015.
- Steele AM, et al. Prevalence of vascular complications among patients with glucokinase mutations among prolonged, mild hyperglycemia. Journal of the American Medical Association. 2014;311(3):279.
- Standards of medical care in diabetes — A position statement of the American Diabetes Association. Diabetes Care. 2015;38(suppl):S33.