Management of Infection‑Associated Hyperglycemia

Epidemiology and Clinical Impact

Approximately two‑thirds of patients hospitalized with acute illness develop stress‑induced hyperglycemia, which is independently linked to higher mortality and morbidity rates. 1
In surgical populations, stress hyperglycemia is associated with increased postoperative infection rates and delayed wound healing. Evidence derives from multiple cohort analyses. 1, 2, 3, 4

Influenza infection raises the incidence of abnormal glucose excursions by roughly 75 % in individuals with type 2 diabetes. (Observational data) 5, 6
Sepsis frequently disrupts glucose homeostasis, leading to hyperglycemia or hypoglycemia. (Critical‑care cohort) 7
Acute severe illness can trigger diabetic ketoacidosis in patients with underlying susceptibility. (Case‑series) 8

Blood glucose should be measured in every patient presenting with sepsis or any acute infection. (Intensive‑care guideline) 7
An altered mental state predicts hypoglycemia in septic patients with 86 % specificity; therefore, glucose assessment is crucial in this subgroup. 7
Additional risk factors prompting routine glucose monitoring include:
- Known diabetes or metabolic‑syndrome. 2, 3, 4
- Age > 60 years. 2, 3, 4
- Prior episode of transient hyperglycemia. 2, 3, 4

Maintain serum glucose between 70–180 mg/dL (4–10 mmol/L) for all infected patients. (Critical‑care recommendation) 7
Keep glucose ≥70 mg/dL (≥4 mmol/L) to avoid hypoglycemia. 7
Do not aim for tight control <150 mg/dL (<8.3 mmol/L) because of an elevated risk of dangerous hypoglycemic events. 7
In patients with pre‑existing diabetes, mortality rises when glucose exceeds 180 mg/dL (10 mmol/L). 2, 3, 4
In patients without diabetes, mortality rises when glucose exceeds 140 mg/dL (7.8 mmol/L). 2, 3, 4

Certain infections (e.g., malaria) and late‑stage sepsis can cause hypoglycemia, especially in malnourished individuals, children, or those with chronic liver disease. (Intensive‑care observation) 7
When glucose measurement is impossible in a patient with impaired consciousness, presume hypoglycemia and administer 30–50 g of intravenous glucose. 7
Stress‑induced hyperglycemia in previously non‑diabetic patients carries a worse prognosis than comparable glucose levels in known diabetics. (Retrospective analyses) 2, 3, 4

Acute illness triggers metabolic and endocrine abnormalities that lead to hyperglycemia, often called "stress diabetes" or "diabetes of injury" 9
During acute stress, hepatic glucose production increases through upregulation of both gluconeogenesis and glycogenolysis, despite high serum insulin levels, indicating insulin resistance during acute illness 9
Several hormonal factors contribute to this hyperglycemic state, including increased levels of glucagon, cortisol, growth hormone, catecholamines, and cytokines, which stimulate glucose production and impair peripheral insulin-mediated glucose uptake 9

Elevated serum glucose is common in the acute phase of illness, present in approximately two-thirds of patients with acute ischemic stroke 10, 11
Hyperglycemia during acute illness is associated with increased mortality and morbidity, longer hospital stays, and higher healthcare costs 9, 10, 11
The risk of hemorrhagic transformation in acute ischemic stroke increases by 75% per 100 mg/dL increase in blood glucose 10, 11

In acute ischemic stroke, hyperglycemia is associated with infarct expansion and hemorrhagic conversion, and elevated glucose levels may prevent early reperfusion and reduce the benefit of thrombolytic therapy 10, 11
In critical illness, hyperglycemia is linked to increased risk of in-hospital mortality and congestive heart failure, and even mild elevations of fasting glucose in patients with coronary artery disease undergoing procedures have been associated with substantial mortality risk 9

During infection, the body shifts to catabolic processes to meet increased energy demands, triggered by inflammatory cytokines and stress hormones 12
Hyperglycemia redirects glucose to immune cells promoting aerobic glycolysis in early stages of infection, but hypoglycemia may develop in later stages of sepsis due to peripheral glucose usage and anorexia 12

The American Heart Association recommends monitoring blood glucose levels during acute illness, using rapid-acting insulin for blood glucose levels >140 mg/dL in acute ischemic stroke, and minimizing glycemic variability and avoiding hypoglycemia 10, 11, 13
Intensive insulin therapy to maintain normoglycemia has shown mixed results, with some studies demonstrating reduced mortality and morbidity, while others show no significant benefit in clinical outcomes 9, 10, 11, 14

Infection triggers a surge of counter‑regulatory hormones (cortisol, epinephrine, glucagon, growth hormone) that increase insulin resistance and stimulate hepatic gluconeogenesis, leading to hyperglycemia in both diabetic and non‑diabetic patients. 15

Peri‑operative hyperglycemia > 180 mg/dL (10 mmol/L) independently raises morbidity, infection risk, and mortality. 16
Adults > 60 years with acute infection should have routine glucose monitoring because they are at higher risk for stress‑induced hyperglycemia. 16
Patients with known diabetes or metabolic syndrome require systematic glucose monitoring during any acute infection. 16
A prior episode of transient hyperglycemia identifies individuals who are prone to develop infection‑related hyperglycemia and therefore merit close monitoring. 16
In patients with pre‑existing diabetes, mortality increases when glucose exceeds 180 mg/dL (10 mmol/L). 16
In patients without diabetes, mortality rises when glucose exceeds 140 mg/dL (7.8 mmol/L). 16

Measure capillary or plasma glucose every 2–4 hours during acute infection when hyperglycemia is present. 17
Employ continuous glucose monitoring or frequent self‑monitoring for patients receiving insulin therapy during infection. 17

Initiate a continuous intravenous insulin infusion (e.g., electronic syringe) when glucose persistently exceeds 180 mg/dL (10 mmol/L). 18
Aim for a target glucose range of 90–180 mg/dL (5–10 mmol/L) while on insulin infusion. 18

Continue existing insulin regimens without interruption, adjusting doses based on frequent glucose checks. 17
For type 1 diabetes or insulin‑requiring type 2 diabetes, use continuous intravenous insulin infusion during severe infection. 18

Discontinue metformin during acute infection because of dehydration risk and potential lactic acidosis. 17
Stop SGLT2 inhibitors (e.g., canagliflozin, dapagliflozin, empagliflozin) during infection due to heightened risk of ketoacidosis and dehydration. 17
Continue DPP‑4 inhibitors (e.g., alogliptin, linagliptin, saxagliptin, sitagliptin) as they are generally well tolerated in the infectious setting. 17
Monitor GLP‑1 receptor agonists closely for signs of dehydration; ensure adequate fluid intake and regular meals. 17

Intensify metabolic control in diabetic individuals before infection to lower the risk of severe infectious complications. 17
Target an HbA1c < 6.5% when feasible, as higher HbA1c levels are associated with increased infection frequency and severity. 15