Glucose is the main sugar produced in the body from digested foods. Glucose is transported by the bloodstream to produce energy for cells. When blood glucose levels are too high, a condition called hyperglycemia, it can cause complications, including infection. Hyperglycemia affects the immune system -- the system that defends your body against infections. Infection with hyperglycemia is a complex process that involves a cascade of symptoms and systems.
Inflammation
When infection is present, inflammation occurs as a response to help fight the infection. The inflammatory response depends on the adequacy of blood cells, sufficient energy and nutrients. Conditions in which any of these are compromised may result in an insufficient response. Patients who are malnourished or immunosuppressed may be unable to defend the body against infection. Those who have compromised blood flow and oxygen to the tissues, such as diabetic patients or patients with respiratory failure, are also at risk.
High Blood Sugar
The most common complications associated with high glucose levels are dehydration and electrolyte imbalances. High levels of glucose will cause a shift in sodium and potassium, which can lead to low blood pressure, renal failure and abnormal heart beats in addition to nerve and muscle dysfunction. Insulin is a hormone produced by the pancreas that helps move glucose from the bloodstream into the cells. If insulin is not present or responding effectively, it will result in high blood glucose levels. According to "Clinical Practice of Emergency Medicine," serious medical illness and surgery produce a state of insulin resistance and insulin deficiency, resulting in hyperglycemia. It has been shown to be important to maintain near normal blood glucose levels, around 100 mg/dL, to help decrease infection rates.
Immune System
The body's immune system is the primary defense against infection. The immune system is made up of white blood cells, tissues and organs that work to fight off infectious agents. White blood cells, called leukocytes play a major role in attacking and destroying organisms that cause disease. Hyperglycemia depresses the immune system and the inflammatory response. Inflammation is a protective response to injury or infection. Once the immune system is impaired, the body does not have the reserve to protect itself from infection.
Decreased Blood Flow
Hyperglycemia can cause abnormal lipid metabolism that results in high cholesterol, high triglycerides, and atherosclerosis. The combination of these three increases plaque build-up in the arteries, leading to high blood pressure and poor circulation. Blood carries necessary oxygen and nutrients to the tissues. If blood flow is impaired, the risk of infection increases.
Outcomes
The combination of hyperglycemia and infection can cause adverse outcomes in acutely ill patients with or without diabetes. According to "Nursing 2007," surgical site infections account for 14 percent to 16 percent of all hospital-acquired infections. Glucose control in surgical patients has demonstrated a decrease in infection rates and improved the mortality and morbidity among surgical patients.
References
- "Critical Care Nursing Quarterly"; The Importance of Normoglycemia in Critically Ill Patients; Monica DiNardo et al.; 2004
- "Nursing 2007"; Improving Hospital Care for Surgical Patients; S.Daniels; August 2007
- "Clinical Practice of Emergency Medicine"; A. Harwood-Nuss et al.; 2010
