Stress hyperglycemia

Overview
Stress hyperglycemia is a medical term referring to transient elevation of the blood glucose due to the stress of illness. It usually requires no specific treatment and resolves spontaneously, but must be distinguished from various forms of diabetes mellitus.

It is often discovered when routine blood chemistry measurements in an ill patient reveal an elevated blood glucose. Blood glucose can be assessed either by a bedside ‘fingerstick’ glucose meter or plasma glucose as performed in a labarotory (the latter being more efficacious). A retrospective cohort study by the Mayo Clinic held that bedside glucometry was a reliable estimate of plasma glucose with a mean difference of 7.9 mg/dL, but still may not coincide with every individual PMID 15888855. The glucose is typically in the range of 140-300 mg/dl (7.8-16.7 mM) but occasionally can exceed 500 mg/dl (28 mM), especially if amplified by drugs or intravenous glucose. The blood glucose usually returns to normal within hours unless predisposing drugs and intravenous glucose are continued.

Stress hyperglycemia is especially common in patients with hypertonic dehydration and those with elevated catecholamine levels (e.g., after emergency department treatment of acute asthma with epinephrine). Steroid diabetes is a specific and prolonged form of stress hyperglycemia.

In some people, stress hyperglyemia may indicate a reduced insulin secretory capacity or a reduced sensitivity, and is sometimes the first clue to incipient diabetes. Because of this, it is occasionally appropriate to perform diabetes screening tests after recovery from an illness in which significant stress hyperglycemia occurred.

One of the most sweeping changes in intensive care unit and post-surgical care in recent years is the trend toward more aggressive treatment of hyperglycemia of all causes in hospitalized patients. A number of research studies of the last decade have demonstrated that even mildly elevated blood glucose levels (110 mg/dL or 6.1 mmol/L) in a hospital intensive care unit (ICU) can measurably increase the morbidity and mortality of such patients. According to a randomized control trial (RCT) of over 1500 surgical intensive care unit (ICU) patients, controlling patients’ blood glucose below 110 mg/dL or 6.1 mmol/L significantly decreased mortality from 8% with conventional treatment to 4.6% PMID 11794168. Intensive insulin therapy also decreased bloodstream infections by 46%, acute renal failure requiring dialysis or hemofiltration by 41%, the median number of red-cell transfusions by 50%, and critical-illness polyneuropathy by 44%. A subsequent RCT of 1200 medical ICU patients found that intensive insulin therapy significantly reduced morbidity but not mortality among all patients in the medical ICU PMID 16452557. It is becoming increasingly common to treat hospital patients with "stress hyperglycemia" aggressively, usually with insulin.