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    Sepsis and Septic Shock – Diagnosis

    Critical Care / Resuscitation, Infections

    Last Updated Aug 21, 2018
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    • In 2016, the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) defined sepsis as a “life-threatening organ dysfunction caused by a dysregulated host response to infection” (1).
    • Sepsis is now identified by an increase of at least 2 points in the Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score in patients with a suspicion of infection.
    • The quick SOFA (qSOFA) score, a surrogate for SOFA in settings in which all components of SOFA are not routinely measured (i.e. Emergency Department) was introduced to screen for patients likely to have sepsis.
    • In the Emergency Department qSOFA has been shown to be more sensitive and specific than SOFA, SIRS or the old definition of severe sepsis to predict in-hospital mortality.
    • Although SIRS and lactate are no longer part of the definitions of sepsis, SIRS remains a sensitive tool to screen for infection and an elevated lactate continues to be strongly correlated with in-hospital mortality.
    • Base deficit or anion gap measurement are poor surrogates for lactate measurement. Centers should have capacity for measuring lactate.


    SIRS – 2/4 of heart rate > 90/min, respiratory rate >20/min, temperature > 38’C or < 36’C, WBC >12 or <4 (altered mental status often substituted for WBC at triage)

    qSOFA – 2/3 of Altered Mental Status, Respiratory Rate >20/minute,  Systolic Blood Pressure < 100 mmHg. In ED, this correlates to a 10% in-hospital mortality.

    SOFA – Sequential Organ Failure Assessment Score (see Figure)

    Sepsis – Infection with evidence of organ dysfunction (increase in SOFA score of greater or equal to 2). Correlates to a 10% in-hospital mortality.  (see Figure)

    Septic Shock – requirement of vasopressors to keep mean arterial pressure greater than 65 mmHg AND a serum lactate > 2 mmol/L.  Correlates to a 40% in-hospital mortality.

    Diagnostic Process

    • Detailed history and physical exam to determine source of sepsis and evidence of organ dysfunction (i.e. low urine output, mottling of extremities)
    • Blood work to screen for organ dysfunction to confirm sepsis diagnosis as well to look for sepsis mimics (i.e. CBC, extended electrolytes, BUN, Cr, glucose, LFTs, Lipase, Lactate)
    • Culture appropriate sites (blood, urine, sputum, stool, wounds)
    • Imaging to help determine site and extent of infection; based on clinical exam, look for drainable focus of infection (ie Chest and other x-rays, CT scans, Ultrasounds, MRI)

    Quality Of Evidence?


    • The new sepsis-3 definitions were derived from a database of over 1.3 million patient encounters and have been externally validated.
    • The qSOFA score has been externally validated in the Emergency Department.

    Figure: SOFA Score

    Sepsis Diagnosis SOFA Figure

    Related Information

    Reference List


    Relevant Resources


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