Sepsis is described as an autodestructive process that permits extension of the normal pathophysiologic response to infection to involve otherwise normal tissues and results in MODS. Organ dysfunction or organ failure may be the first clinical sign of sepsis, and no organ system is immune from the consequences of the inflammatory excesses of sepsis. Mortality increases as organ failure increases.
Although uncontrolled, once MODS develops systemic evidence of both proinflammatory and anti-inflammatory up-regulation are usually present, suggesting that failure of host defense homeostasis is the final pathway from sepsis to MODS, rather than simple hypotension-induced end-organ injury, as may occur with hemorrhagic shock. Survival from severe sepsis with MODS is usually associated with a generalized reduction in both the proinflammatory and anti-inflammatory response.
A novel hypothesis has recently emerged that survival from severe sepsis requires a generalized down-regulation of the body’s immune response, energetic functions, and associated organ performance. Thus, MODS may by the host’s adaptive response to overwhelming inflammation, allowing inflammation to clear without causing permanent end-organ harm. As discussed below, all organs reveal a generalized hyporesponsiveness that is clearly abnormal in health but may mark a survival strategy in severe sepsis.
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Stages of sepsis based on American College of Chest Physicians/Society of Critical Care Medicine Consensus Panel guidelines.
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Pathogenesis of sepsis and multiorgan failure.
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Venn diagram showing overlap of infection, bacteremia, sepsis, systemic inflammatory response syndrome (SIRS), and multiorgan dysfunction.
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Acute respiratory distress syndrome (ARDS) present in this chest x-ray (CXR) film is a common organ system affected in multiorgan failure of sepsis.
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Acute respiratory distress syndrome (ARDS) shown in this chest x-ray (CXR) film is a common complication of septic shock. Note bilateral airspace infiltration, absence of cardiomegaly, vascular redistribution, and Kerley B lines.
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Organizing phase of diffuse alveolar damage (ARDS) secondary to septic shock shows diffuse alveolar injury and infiltration with inflammatory cells.
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Organizing diffuse alveolar damage in a different location showing disorganization of pulmonary architecture.
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A high-power view of organizing diffuse alveolar damage (ARDS) shows hyperplasia of type II pneumocytes and hyaline membrane deposits.