Sepsis and septic shock Flashcards
How is sepsis defined?
Life threatening organ dysfunction caused by dysregulated host response to infection
How is organ dysfunction graded in sepsis?
SOFA score
What SOFA score identifies sepsis?
> 2 consequent to infection
What is septic shock?
Sepsis with persisting hypotension requiring vasopressors to maintain MAP of over >65mmHg with serum lactate >2mmol/l despite adequate volume resus
What are the criteria in qSOFA?
Hypotension - Systolic BP<100
Altered mental status - GCS<15
Tachypnoea - RR>22
What does qSOFA stand for?
Quick Sequential Organ Failure Assessment
What physical barrier does the body have against sepsis?
Skin
Mucosa
Epithelial lining
How does the innate immune system protect the body from sepsis?
IgA in GI tract
Dendritic cells
Macrophages
How does sepsis originate?
Breach of integrity of host barrier - physical or immunological
Organism enters the blood stream
What is the pathophysiology of sepsis?
Uncontrolled inflammatory response
Features consistent with immunosuppression - loss of delayed hypersensitivity, inability to clear infection, predisposition to nosocomial infection
What are the three phases in sepsis pathogenesis?
Release of bacterial toxins
Release of mediators
Effects of specific excessive mediators
What are common toxins released by bacteria in sepsis?
Gram negative - Lipopolysaccharide
Gram positive - Microbial-associated molecular pattern
Superantigens
What are examples of superantigens?
Staphylococcal toxic shock syndrome toxin
Streptococcal exotoxins
What happens as a result of exotoxin release?
Pro-inflammatory response - small amounts of superantigens cause a large amount of mediators to be secreted
What are the 2 types of mediators?
Pro-inflammatory
Anti-inflammatory
What effects does excessive pro-inflammatory mediators have?
Promote endothelial cell - leukocyte adhesion
Release arachidonic acid metabolites
Complement activation
Vasodilation of blood vessels by Nitric Oxide
Increase coagulation by release of tissue factors and membrane coagulants
Cause hyperthermia
What effects does excessive anti-inflammatory mediators have?
Inhibit TNF alpha
Augment acute phase reaction
Inhibit activation of coagulation system
Provide negative feedback mechanisms to pro-inflammatory mediators
What is the outcome of sepsis when pro-inflammatory mediators outbalance anti-inflammatory mediators?
Septic shock with multiorgan failure and death
What is the outcome of sepsis when anti-inflammatory mediators outbalance pro-inflammatory mediators?
Immunoparalysis with uncontrolled infection and multiorgan failure
What are neurological features of sepsis?
Altered consciousness
Confusion
Psychosis
What are respiratory features of sepsis?
Tachypnoea
PaO2<70mmHg
Sats<90%
What are liver features of sepsis?
Jaundice
Raised LFTs
Decrease albumin
Increased prothrombin time
What are haematological features of sepsis?
Decreased platelets
Increased prothrombin time/activated prothromboplastin time
decreased CRP
Increased D-dimer
What are cardio features of sepsis?
Tachycardia
Hypotension
What are renal features of sepsis?
Oliguria
Anuria
Increased creatinine
What are general features of sepsis?
Fever >38 - chills, rigors, flushes, cold sweats
Hypothermia in young and elderly - immunosuppressed
Tachycardia >90
Tachypnoea>20
Altered mental status
Hyperglycaemia in absence of diabetes
What is leucocytosis?
WCC>12/l
What is leucopenia?
WCC<4/l
What are features of perfusion in sepsis?
High lactate
Skin mottling and reduced capillary fusion
What factors of the host affect sepsis presentation?
Age
Co-morbidities ie COPD, diabetes, etc
Immunosuppression - HIV, drug induced, congenital
Previous surgery
What factors of the causative organism effect sepsis presentation?
Gram positive or negative
Virulence factors
Bioburden
What environmental factors effect sepsis presentation?
Occupation
Travel
Hospitilisation
What is SIRS?
Systemic Inflammatory Response Syndrome
What is the sepsis 6?
Take blood cultures Take blood lactate Take urine output Give Oxygen Give IV antibiotics Give IV fluids
What is the time frame for the sepsis 6?
Within an hour of presenting
Why do we take blood cultures?
Make a microbiological diagnosis
How many blood cultures should be taken?
2
Why do we take lactate?
It is a measure of generalised hypoperfusion
Why do we take urine output?
Marker of renal dysfunction
What is type A lactate a sign of?
Hypoperfusion
What is type B lactate a sign of?
Mitochondrial toxins
Alcohol
Malignancy
Metabolism errors
How much fluid is given in sepsis?
30ml/kg
When should HDU referral be considered?
Low BP responsive to fluids Lactate>2 despite fluid resus Elevated creatinine Oliguria Liver dysfunction Bilateral infiltrates
When should ITU be considered?
Septic shock
Multi-organ failure
Requires sedation, intubation, and ventilation
