What does "hyperglycemia" mean and what conditions cause it?

Hyperglycemia means high blood sugar, from hyper meaning excessive, glyc meaning sugar, and emia meaning blood condition. Normal fasting blood glucose is 70 to 100 milligrams per deciliter. Hyperglycemia is defined as fasting glucose above 126 or random glucose above 200. The primary cause is diabetes mellitus, where either the pancreas does not produce enough insulin, as in type 1, or the body's cells resist insulin's effects, as in type 2. Other causes include stress, infection, corticosteroid medications, and Cushing syndrome.