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. The relationship runs in both directions: high glucose impairs immune function and wound healing, while infection itself worsens glucose control through physiologic stress. Each is a reason to measure glucose more often during acute illness and to assess hydration and kidney function at the same time. It may also be the first clue...