What is the definition of Sepsis (Systemic Inflammatory Response Syndrome)?

From the Guidelines

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. This definition is based on the most recent and highest quality study, which emphasizes the importance of identifying organ dysfunction in addition to infection 1. The presence of an aberrant host response to the underlying infection and the presence of organ dysfunction differentiates sepsis from simple infection.

Key Characteristics of Sepsis

• Life-threatening organ dysfunction
• Dysregulated host response to infection
• Presence of organ dysfunction in addition to infection
• Can manifest as altered mental status, difficult breathing, low blood pressure, high heart rate, fever or low body temperature, and decreased urine output

Clinical Criteria for Sepsis

• Sequential Organ Failure Assessment (SOFA) score
• Quicker qSOFA screening tool, which looks for respiratory rate ≥22/min, altered mental status, and systolic blood pressure ≤100 mmHg

Importance of Early Recognition and Treatment

Early recognition of sepsis is crucial, as it requires immediate treatment with broad-spectrum antibiotics, intravenous fluids, and organ support as needed 1. The underlying pathophysiology involves an overwhelming inflammatory response that damages the body's own tissues and disrupts normal blood flow to vital organs. Without prompt treatment, sepsis can rapidly progress to septic shock, characterized by profound circulatory, cellular, and metabolic abnormalities that substantially increase mortality risk.

Risk Factors and Incidence

Risk factors for the development of sepsis include immune compromise, chronic diseases, and certain patient demographics 1. The global incidence of sepsis is estimated to be 48.9 million cases, with 11 million sepsis-related deaths, highlighting the need for prompt recognition and treatment.

From the Research

Definition of Sepsis

• Sepsis is a clinical syndrome that results from the dysregulated inflammatory response to infection that leads to organ dysfunction 2.
• It can be defined as life-threatening organ dysfunction caused by a dysregulated host response to infection 3.
• Sepsis is the systemic inflammatory response to infection frequently associated with hypoperfusion followed by tissue injury and organ failure 4.

Key Characteristics

• The dysregulated inflammatory response to infection leads to organ dysfunction 2.
• Organ dysfunction can be represented by an increase in the Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score of 2 points or more, which is associated with an in-hospital mortality greater than 10% 3.
• Sepsis can be identified by a combination of clinical criteria, including respiratory rate, altered mentation, and systolic blood pressure 3.

Pathophysiology

• The activation of monocytes/macrophages and neutrophils, with the consecutive release of pro-inflammatory mediators and activation of the coagulation cascade, seems to play a key role in the pathogenesis of sepsis 4.
• The inflammatory reaction is mediated by the release of cytokines, including tumor necrosis factor-alpha, interleukins, and prostaglandins, from neutrophils and macrophages 5.
• The cytokines activate the extrinsic coagulation cascade and inhibit fibrinolysis, resulting in microvascular thrombosis and organ dysfunction 5.