Glycemic

Hospital hyperglycemia is not limited to people with known diabetes. Severe infection, surgery, trauma, myocardial infarction, pain, and other physiologic stressors trigger cortisol, catecholamines, glucagon, growth hormone, and inflammatory cytokines. These signals tell the liver to release glucose while making muscle and adipose tissue less responsive to insulin. The result is insulin resistance with relative insulin deficiency. Glucose rises even when the patient has never carried a diabetes diagnosis. Treatment can add to the problem. Glucocorticoids increase hepatic glucose production and insulin resistance. Enteral feeds, parenteral nutrition, dextrose-containing IV fluids, and vasopressors can also drive hyperglycemia. An abrupt interruption of nutrition after insulin has been given reverses that balance quickly and can cause hypoglycemia. Hyperglycemia is associated with infection, impaired wound healing, prolonged admission, and increased mortality. It may also be the first clue to previously unrecognized diabetes. The bedside question is not simply, “Is the glucose high?” Ask, “What is driving it, and is the current insulin plan matched to illness severity and nutritional intake?”