From the Guidelines

Sepsis is a life-threatening condition caused by a dysregulated host response to infection, leading to organ dysfunction.

The pathophysiology of sepsis involves a complex interplay between the host's immune response and the infecting microorganism, resulting in an uncontrolled inflammatory response that can lead to multiple organ failure 1.
The dysregulated host response is characterized by an imbalance between pro-inflammatory and anti-inflammatory mechanisms, leading to tissue damage and organ dysfunction 1.
The inflammatory response is mediated by the release of cytokines and other inflammatory mediators, which can lead to vasodilation, increased vascular permeability, and coagulation abnormalities 1.
The organ dysfunction associated with sepsis can affect multiple organ systems, including the cardiovascular, respiratory, renal, and hepatic systems, and can lead to septic shock, a condition characterized by profound circulatory, metabolic, and cellular abnormalities 1.
The definition of sepsis has evolved over time, and the current definition emphasizes the presence of life-threatening organ dysfunction caused by a dysregulated host response to infection 1.
Early recognition and treatment of sepsis are critical to improving outcomes, and prompt intervention can help to prevent the progression of sepsis to septic shock and multiple organ failure 1.

From the Research

Sepsis is a life-threatening condition and a global disease burden, defined as severe organ dysfunction caused by a dysregulated host response to infection 2, 3.
The pathophysiology of sepsis involves a complex interaction between the host's immune response and the invading pathogen, leading to multiple organ dysfunction 3, 4.

The host response to infection triggers an initial exaggerated inflammatory-immune response, which can lead to activation or suppression of multiple downstream pathways, resulting in organ dysfunction 3, 5.
The immune response can be divided into two phases: an initial hyperinflammatory phase, followed by an immunoparalysis phase, also known as compensatory anti-inflammatory response syndrome (CARS) 5.
The immune response is characterized by the release of various inflammatory mediators, which orchestrate the intense inflammation through complicated cellular interactions 5.

Sepsis is associated with multiple organ dysfunction, including alterations in the coagulation system, which can lead to life-threatening complications 4, 6.
Coagulation abnormalities are a key component of sepsis pathophysiology, and therapies targeting the coagulation system have been approved for the treatment of severe sepsis 6.

Sepsis is a heterogeneous disease, with substantial variability in the host's inflammatory response, cellular changes, and metabolic alterations 3, 6.
The pathophysiology of sepsis is complex and multifactorial, involving multiple mediators, systems, and pathways, and no single mediator or system drives the disease process 6.