From the Guidelines
Sepsis is diagnosed using the Sequential Organ Failure Assessment (SOFA) score or the quicker qSOFA criteria when a patient has a suspected infection, with the most recent and highest quality study suggesting that sepsis is characterized by life-threatening organ dysfunction caused by a dysregulated host response to infection 1. The diagnosis of sepsis involves identifying patients with a suspected infection and organ dysfunction, which can be assessed using the SOFA score or qSOFA criteria.
- The SOFA score evaluates six organ systems (respiratory, cardiovascular, hepatic, coagulation, renal, and neurological) with points assigned for dysfunction in each system.
- A SOFA score increase of 2 or more points indicates sepsis.
- For rapid bedside assessment, qSOFA requires at least two of three criteria: respiratory rate ≥22 breaths/minute, altered mental status, or systolic blood pressure ≤100 mmHg. The qSOFA criteria are supported by the most recent study from 2020, which suggests that these criteria can be used to quickly identify patients with sepsis 1. Additional diagnostic criteria include:
- Elevated lactate levels (>2 mmol/L), which may indicate tissue hypoperfusion
- Positive blood cultures, though treatment should not be delayed while waiting for culture results Vital signs typically show:
- Tachycardia (heart rate >90 beats/minute)
- Fever (>38°C) or hypothermia (<36°C) Laboratory findings often reveal:
- Leukocytosis (>12,000/μL) or leukopenia (<4,000/μL)
- Thrombocytopenia
- Elevated C-reactive protein
- Procalcitonin Early recognition and treatment of sepsis are crucial, as mortality increases significantly with each hour treatment is delayed, as highlighted in a 2017 study 1. Initial management includes:
- Obtaining cultures
- Administering broad-spectrum antibiotics within one hour
- Providing intravenous fluids for patients with hypotension or elevated lactate It is essential to note that the definition of sepsis has evolved over time, with the most recent definition emphasizing the importance of organ dysfunction caused by a dysregulated host response to infection, as stated in a 2020 study 1.
From the Research
Criteria for Diagnosing Sepsis
The diagnosis of sepsis involves several criteria, including:
- Suspected or proven infection
- Organ failure
- Signs that meet two or more criteria for the systemic inflammatory response syndrome (SIRS) 2 Some of the key signs of SIRS include:
- Body temperature greater than 38°C or less than 36°C
- Heart rate greater than 90 beats per minute
- Tachypnea, with more than 20 breaths per minute
- White blood cell count greater than 12,000 cells/mm³ or less than 4,000 cells/mm³
Systemic Inflammatory Response Syndrome (SIRS) Criteria
The SIRS criteria are used to define severe sepsis, and include:
- Two or more of the following conditions:
- Body temperature greater than 38°C or less than 36°C
- Heart rate greater than 90 beats per minute
- Tachypnea, with more than 20 breaths per minute
- White blood cell count greater than 12,000 cells/mm³ or less than 4,000 cells/mm³ 2 However, a study found that the need for two or more SIRS criteria to define severe sepsis excluded one in eight otherwise similar patients with infection, organ failure, and substantial mortality 2
Risk Factors for Sepsis Complications
Several risk factors have been identified for sepsis complications, including:
- Acute kidney injury (AKI): lower platelet counts, elevated procalcitonin levels, and higher SOFA scores 3
- Septic shock: lower platelet counts, higher white blood cell counts, age, procalcitonin, SOFA score, and Pitt bacteremia score 3
- Acute respiratory distress syndrome (ARDS): lower platelet counts, higher body weight, and elevated alanine aminotransferase levels 3
Pathophysiology of Sepsis
Sepsis is characterized by a dysregulated host response to infection, which can progress to septic shock and lead to various complications 4, 3 The pathophysiology of sepsis involves an exaggerated systemic inflammatory response, which can cause organ failure and death 4