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

• Tissue hypoperfusion leads to septic shock

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

• Reactive leukocytosis
• Thrombocytopenia
• Coagulopathy
• Hyperglycemia
• Elevated plasma C-reactive protein
• Arterial hypoxia
• Hyperlactatemia
• Results of organ dysfunction

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

 

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