Sepsis

Sepsis

Updated: 06/28/2022

© Jun Wang, MD, PhD

 

Definition

  • Life threatening organ dysfunction caused by a dysregulated host response to infection

General features

  • Organ dysfunction identified by acute change of 2 or more points in total SOFA score or qSOFA
  • Likely prolonged ICU stay
  • Relatively high mortality rate
  • Commonly associated with infections of injury or internal organs and perforation/rupture of abdominal/pelvic structures
  • Most commonly caused by bacterial infections, but can be caused by virus or fungi

Systemic Inflammatory Response Syndrome (SIRS)

  • A term being abandoned since 2016
  • Still being used clinically
  • Poor mortality prediction comparing with Sequential Organ Failure Assessment (SOFA)
  • Clinical responses to either infectious or non-infectious causes

Sequential Organ failure Assessment (SOFA)

  • A systemic evaluation of organ function
  • Performed in critically ill patients with suspected sepsis
  • Systems involved

o   Cardiovascular: Blood pressure

o   Neurological: Coma scale

o   Respiratory: PaO2/FIO2

o   Coagulation: Platelets count

o   Liver function: Bilirubin

o   Renal function: Urine output, Creatinine

  • An increase of score of 2 or more from baseline associated with significantly increased risk of mortality
  • Baseline SOFA score is presumed to be zero unless pt has known organ dysfunction prior to infection

Quick SOFA (qSOFA)

  • Simplified criteria to identify high risk patients with suspected infection
  • Similar predictive validity
  • An increase of score of 2 or more from baseline associated with significantly increased risk of mortality
  • Baseline SOFA score is presumed to be zero unless pt has known organ dysfunction prior to infection
  • Three criteria

o   Respiratory rate 22/min or greater

o   Altered mentation

o   Systolic blood pressure 100 mm Hg or lower

Risk factors

  • Intensive care unit admission
  • Bacteremia
  • ≥65 years 
  • Immunocompromised: Deficiency or suppression
  • Diabetes and obesity
  • Underlying malignancy
  • Community acquired pneumonia 
  • Previous hospitalization

Key pathogenesis

  • Excessive inflammatory reaction to infection
  • Over activation of proinflammatory cytokines, growth factors, etc, such as TNF and IL-1
  • Continuous activation of inflammatory cells and release of more cytokines
  • Systemic dysfunction

o   Endothelial dysfunction: elevated adhesin promotes leukocytes infiltrate surrounding tissue

o   Coagulopathy: Activation of coagulation cascades may lead to disseminated intravascular coagulation

o   Cellular dysfunction: Increased catabolism, insulin resistance, hyperglycemia, etc

o   Cardiovascular dysfunction: Decreased vascular resistance, normal or increased cardiac output, reduced ejection fraction

Pathophysiology



Clinical presentations

  • Symptoms and signs associated with site of infection
  • Arterial hypotension
  • Fever
  • Tachypnea
  • Tachycardia
  • Warm and flushed skin in early phase
  • Cool skin if septic shock occurs
  • Altered mental status
  • Oliguria or anuria
  • Ileus or absent bowel sound

Key Laboratory findings

o   Kidney: Elevated creatinine

o   Liver: Hyperbilirubinemia

o   Adrenal: Hyponatremia, hyperkalemia

  • Microbiology studies: Positive culture NOT necessary, many pts have negative culture and empiric antibiotics can be issue without culture results

Diagnosis

  • Based on clinical and laboratory findings
  • Organ dysfunction identified by acute change of 2 or more points in total SOFA score or qSOFA
  • Symptoms and signs of infection
  • Positive culture results, or clinical response to antibiotic treatments

Management

  • Supportive management of organ dysfunction

o   Vasopressor

o   Activated protein C

o   Corticosteroid

o   Glycemic control

o   Resuscitation from septic shock

  • Identification and treatment of underlying infection

o   Empiric antibiotics

 

Back to septic shock

Back to shock

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