Sepsis and Homeostasis

According to the Gale Encyclopedia of Nursing and Allied Health, Sepsis is a systemic infection that spreads rapidly through the bloodstream and body tissues. Sepsis develops as a result of a massive immune response to bacterial infection that begins as a localized infection, but then spreads into the bloodstream. (Oberleitner & Culvert, 2018) Normal immune and physiologic responses eradicate pathogens, and the pathophysiology of sepsis is due to the inappropriate regulation of these normal reactions (Stearns-Kurosawa, Osuchowski, Valentine & Remick, 2011). Sepsis occurs when an infection triggers a localized inflammatory reaction that then spills over to cause systemic symptoms, these clinical symptoms are called the systemic inflammatory response syndrome (Jacobi, 2002).

The systemic inflammatory response syndrome (SIRS) is defined by the presence of two or more of the criteria listed; temperature above 38c or below 36c, Heart Rate greater than 90 beats per minute, Respiratory rate 20 or PaCO2 <32 mm Hg, White Blood Cell Count >12 K or <4 K mm?€’3, or >10% bands. (Sterns- Kurosawa et. Al, 2011). Additional symptoms include significantly less urine output, sudden changes in mental state, and acute abdominal pain. (Oberleitner & Culvert, 2018) This combination of symptoms help clinicians to recognize sepsis, and take steps to combat the infection. The origin of sepsis can be traced to any place where bacteria can enter the body. This can occur in a variety of different ways, common causes include wounds from injury, invasive medical procedures, IV lines, urinary catheters, or surgical wounds. People whose immune systems are repressed, such a cancer patients or people on immunorepressive medications also have a heightened risk of developing sepsis (Oberleitner & Culvert, 2018).

In a healthy immune response, when bacteria enter, the inflammatory response is initiated, and the localized responses are enough to eradicate the pathogen. According to Sterns-Kurosawa, this is usually enough to clear out the pathogen. Macrophages will engulf the bacteria, and cytokines will be released and the innate immune response will be initiated. Additionally, neutrophils will phagocytose bacteria and release granules that help to create a hostile environment. (Sterns-Kurosawa et. Al, 2011) Under ideal circumstances, this combination of mediators kills the bacteria, and the host returns to homeostasis. However, Sepsis can occur when bacteria escape, or the body responds in a way that injures itself (Sterns- Kurosawa et. Al 2011).

Bossman and Ward explain that during the inflammatory response, neutrophils and macrophages that are killing bacteria, are also generating byproducts called reactive oxygen species and reactive nitrogen species. If a person develops a hyperimmune response, phagocytes and dendritic cells will become overactive. As time goes on though, they become less effective and this results in degraded immune responses. This leads to a decrease in activation of genes that encode for anti-oxidant enzymes. (Bossman & Ward, 2013) This combination creates an imbalance in the body, which intensifies the SIRS symptoms and intensifies the development of Multi Organ Failure, which can lead to death (Bossman & Ward, 2013). Sepsis is a complex physiological response that develops when the reaction to infection rises to a level that results in other physiological alterations. The bacterial invasion is very powerful, and the body cannot keep up with the strong inflammatory response and its byproducts, thus leading to SIRS, MOF and death.

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