when sugar level is high what is the symptoms
Moderate to severe high blood sugar. If your blood sugar levels are consistently high (usually above 350 mg/dL in adults and above 240 mg/dL in children), you may have moderate to severe symptoms of high blood sugar. These symptoms include: 1  Blurred vision.2  Extreme thirst. 3  Lightheadedness.oderate to severe high blood sugar. If your blood sugar levels are consistently high (usually above 350 mg/dL in adults and above 240 mg/dL in children), you may have moderate to severe symptoms of high blood sugar. These symptoms include: 1  Blurred vision.