What is sepsis (blood infection)?

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From the Guidelines

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

Definition and Causes

  • Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection 1.
  • The condition is caused by an overwhelming immune response to an infection, which can lead to organ failure and death if left untreated.
  • Intra-abdominal infections (IAIs) are a common cause of sepsis, and can be particularly challenging to manage due to the complex anatomy of the abdomen and the presence of a large microbial population 1.

Epidemiology and Risk Factors

  • Sepsis is a major global health problem, with an estimated 48.9 million cases and 11 million deaths annually 1.
  • Risk factors for sepsis include immune compromise, chronic diseases such as malignancy, and certain patient demographics (e.g. infants, elderly persons, males, Black race) 1.
  • The incidence of sepsis is rising due to an aging population and the increasing prevalence of chronic diseases 1.

Clinical Management

  • Early recognition and treatment of sepsis are crucial to improving outcomes, and typically involve the use of broad-spectrum antibiotics, supportive care (e.g. vasoactive drugs, mechanical ventilation), and careful monitoring of clinical signs and laboratory data 1.
  • The Surviving Sepsis Campaign (SSC) guidelines provide a framework for the management of sepsis, but may not be entirely applicable in low-income settings where resources are limited 1.

From the Research

Definition of Sepsis

  • Sepsis is a life-threatening condition that arises from a systemic blood infection, causing one or more organ damage due to the dysregulation of the immune response 2, 3, 4, 5.
  • It is a clinical syndrome that results from the dysregulated inflammatory response to infection, leading to organ dysfunction 3.
  • Sepsis is defined not only by the presence of an infection but also by organ dysfunction from a dysregulated host response to that infection 4.

Pathophysiology of Sepsis

  • The dysregulated inflammatory response to infection leads to organ dysfunction, which can result in morbidity and mortality 3.
  • The molecular and cellular pathways involved in sepsis pathogenesis include cytokines, the coagulation cascade, apoptosis, and mitochondrial dysfunction 4.
  • Numerous pathways, including proinflammatory and antiinflammatory cytokines, the coagulation cascade, apoptosis, and mitochondrial dysfunction, help determine if a bloodstream infection progresses to sepsis 4.

Diagnosis and Management of Sepsis

  • Current established treatments for sepsis include appropriate antimicrobial agents, optimization of intravascular volume, vasopressors, and high-quality supportive care 3.
  • Laboratory tests, such as C-reactive protein, procalcitonin, and lactic acid, have been evaluated for their utility in sepsis diagnosis, although none are routinely recommended for that purpose in current clinical practice 4.
  • Timely diagnosis is crucial for the outcomes of patients with sepsis and septic shock, and emergency physicians play a critical role in recognizing and beginning emergency treatment of septic patients 5.

Impact of Sepsis

  • Sepsis is a major cause of morbidity and mortality in hospitalized patients, with significant financial burden and impact on society 2, 3, 6.
  • The incidence of sepsis has increased since the first consensus definitions were established in 1991, and it remains one of the leading causes of mortality worldwide 5.
  • Patients who survive severe sepsis are more likely to have permanent organ damage, cognitive impairment, and physical disability 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Sepsis roadmap: What we know, what we learned, and where we are going.

Clinical immunology (Orlando, Fla.), 2020

Research

Sepsis: Current Definition, Pathophysiology, Diagnosis, and Management.

Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition, 2017

Research

Pathologic Difference between Sepsis and Bloodstream Infections.

The journal of applied laboratory medicine, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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