What are the criteria for diagnosing sepsis (Systemic Inflammatory Response Syndrome)?

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Last updated: April 18, 2025View editorial policy

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From the Guidelines

Sepsis is diagnosed when a patient has a suspected or confirmed infection along with evidence of organ dysfunction, as defined by the Sepsis-3 criteria, which is the most recent and widely accepted definition 1. The primary tool for identifying sepsis is the Sequential Organ Failure Assessment (SOFA) score, which evaluates six organ systems: respiratory, cardiovascular, hepatic, coagulation, renal, and neurological.

  • An increase in SOFA score of 2 or more points indicates organ dysfunction consistent with sepsis.
  • For quick bedside assessment, the qSOFA (quick SOFA) criteria can be used, which includes respiratory rate ≥22 breaths/minute, altered mental status, and systolic blood pressure ≤100 mmHg.
  • Two or more qSOFA criteria suggest possible sepsis and the need for further evaluation. Septic shock, a more severe condition, is diagnosed when sepsis is accompanied by persistent hypotension requiring vasopressors to maintain mean arterial pressure ≥65 mmHg and serum lactate >2 mmol/L despite adequate fluid resuscitation, as defined by the Sepsis-3 criteria 1. Earlier definitions included Systemic Inflammatory Response Syndrome (SIRS) criteria, but these are now considered less specific for sepsis diagnosis. Prompt recognition of sepsis is crucial as early intervention with appropriate antibiotics and supportive care significantly improves patient outcomes, as emphasized in the 2017 WSES guidelines for management of intra-abdominal infections 1. The new definition of sepsis suggests that patients with at least 2 of these 3 clinical variables: Glasgow Coma Scale score of 13 or less, systolic blood pressure of 100 mm Hg or less, and respiratory rate 22/min or greater (quick SOFA - qSOFA) may be prone to a poor outcome typical of sepsis 1. The use of qSOFA criteria is recommended for quick bedside assessment, as it is a simple and effective method for identifying patients with sepsis, especially in low-resource settings 1.

From the Research

Criteria for Sepsis

  • Sepsis is a condition characterized by a dysregulated host response to infection, which can progress to septic shock and lead to various complications 2.
  • The criteria for sepsis include a combination of clinical and laboratory findings, such as:
    • Demographic characteristics
    • Laboratory findings at admission (e.g. platelet counts, procalcitonin levels)
    • Treatment outcomes
  • The Sequential Organ Failure Assessment (SOFA) score is an independent predictor of acute kidney injury (AKI) in sepsis patients 2.
  • Other risk factors associated with AKI, septic shock, and acute respiratory distress syndrome (ARDS) in sepsis patients include:
    • Age
    • Procalcitonin levels
    • Pitt bacteremia score
    • Body weight
    • Alanine aminotransferase levels
  • Early identification and close monitoring of these factors are crucial for improving outcomes in sepsis management 2, 3, 4, 5, 6.

Sepsis-Associated Acute Kidney Injury (S-AKI)

  • S-AKI is a frequent complication of sepsis and is associated with increased morbidity and mortality 3, 6.
  • The current diagnostic criteria for AKI have limited early detection, but novel biomarkers of kidney stress and damage have been recently validated for risk prediction and early diagnosis of AKI in the setting of sepsis 6.
  • Microvascular dysfunction, inflammation, and metabolic reprogramming are fundamental mechanisms that may play a role in the development of S-AKI 6.

Acute Respiratory Distress Syndrome (ARDS)

  • ARDS is a devastating complication of severe sepsis, with high mortality rates 4, 5.
  • Timely treatment of underlying sepsis and early identification of patients at risk of ARDS can help to decrease its development 4.
  • Advances in treatment modalities, including lung protective ventilation and extracorporeal membrane oxygenation, have improved outcomes, but further studies are needed to develop novel therapies for sepsis-induced ARDS 4, 5.

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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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