Hyperglycemia usually doesn't cause symptoms until blood sugar (glucose) levels are high — above 180 to 200 milligrams per deciliter (mg/dL), or 10 to 11.1 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 symptoms may become. But some people who've had type 2 diabetes for a long time may not show any symptoms despite high blood sugar levels. Early signs and symptoms Recognizing early symptoms of hyperglycemia can help identify and treat it right away. Watch for:  Frequent urination Increased thirst Blurred vision Feeling weak or unusually tired   Later signs and symptoms If hyperglycemia isn't treated, it can cause toxic acids, called ketones, to build up in the blood and urine. This condition is called ketoacidosis. Symptoms include:  Fruity-smelling breath Dry mouth Abdominal pain Nausea and vomiting Shortness of breath Confusion Loss of consciousness 
hyperglycemia doesn't cause symptoms blood sugar (glucose) levels high — 180 200 milligrams deciliter (mg/dl)  10 11 1 millimoles liter (mmol/l)  symptoms hyperglycemia develop slowly days weeks  longer blood sugar levels stay high  symptoms may become  people who've type 2 diabetes long time may show symptoms high blood sugar levels  early signs symptoms recognizing early symptoms hyperglycemia can help identify treat right away  watch for:  frequent urination increased thirst blurred vision feeling weak unusually tired   later signs symptoms hyperglycemia isn't treated  can cause toxic acids  called ketones  build blood urine  condition called ketoacidosis  symptoms include:  fruity-smelling breath dry mouth abdominal pain nausea vomiting shortness breath confusion loss consciousness 
hyperglycemia