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.
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) with ketones in your urine
Make an appointment with your doctor if:
Jun. 14, 2012
- 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 Feb. 25, 2012.
- 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 Feb. 25, 2012.
- Halter JB, et al. Hazzard's Geriatric Medicine and Gerontology. 6th ed. New York, N.Y.: The McGraw-Hill Companies; 2009. http://www.accessmedicine.com/content.aspx?aID=5133173. Accessed Feb. 25, 2012.
- Longo DL, et al. Harrison's Online. 18th ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://www.accessmedicine.com/content.aspx?aid=9141196Accessed March 1, 2012.
- A1C. American Diabetes Association. http://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/a1c/. Accessed Feb. 25, 2012.
- American Diabetes Association. Standards of medical care in diabetes — 2012. Diabetes Care. 2012;35:S11.
- Humphries RL, et al. Current Diagnosis & Treatment: Emergency Medicine. 7th ed. New York, N.Y.: The McGraw-Hill Companies; 2011. http://www.accessmedicine.com/content.aspx?aID=55757059. Accessed March 1, 2012.
- Collazo-Clavell ML (expert opinion). Mayo Clinic, Rochester, Minn. Feb. 2, 2012.
- Diagnosis and management of type 2 diabetes mellitus in adults. Bloomington, Minn.: Institute for Clinical Systems Improvement. http://www.guideline.gov/content.aspx?id=24137. Accessed March 1, 2012.
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