Sepsis and Septic Shock Flashcards
what is the definition of sepsis?
is defined as life-threatening organ dysfunction caused by dysregulated host response to infection
Organ dysfunction can be identified as an acute change in total SOFA score >2 points consequent to the infection
SOFA score >2 reflects an overall mortality risk of approximately 10% in a general hospital population with suspected infection
what is the traditional model of sepsis?
what is the definition of septic shock?
can be identified with a clinical construct of sepsis with persisting hypotension requiring vasopressors to maintain MAP >65mmHg and having a serum lactate of >2mmol/l despite adequate volume resuscitation
Patients with septic shock have a hospital mortality of 40%
Patients with suspected infection who are likely to have a prolonged ICU stay or die in the hospital can be promptly identified with a ____?
qSOFA
what does qSOFA stand for?
hypotension systolic bp <100
altered mental state
tachypnea RR >22/min
score of >2 criteri suggests greater risk of poor outcome
what is the sepsis 6?
what defences does the body have against sepsis?
Physical barrier – skin, mucosa, epithelial lining
Innate immune system – IgA in gastrointestinal tract, dendritic cells / macrophages
Adaptive immune system – lymphocytes, immunoglobulins
describe the pathophysiology of sepsis?
Uncontrolled inflammatory response
Patients with sepsis have features consistent with immunosuppression:
Loss of delayed hypersensitivity
Inability to clear infection
Predisposition to nosocomial infection
Probable change of the sepsis syndrome over time
Initially there is an increase in inflammatory mediators
Later, there is a shift toward an anti-inflammatory immunosuppressive phase
Depends on the health of the individual patient
what are three phases in the pathogenesis of sepsis?
Release of bacterial toxins
Release of mediators
Effects of specific excessive mediators
what is phase one of sepsis?
Bacterial invasion into body tissues is a source of dangerous toxins
May or may not be neutralised and cleared by existing immune system
what are commonly released toxins in phase one?
Gram negative
Lipopolysaccharide (LPS)
Gram positive
Microbial-associated molecular pattern (MAMP)
Lipoteichoic acid
Muramyl dipeptides
Superantigens
Staphylococcal toxic shock syndrome toxin (TSST)
Streptococcal exotoxins
what is phase two of sepsis?
Release of mediators in response to infection
Effects of infections due to endotoxin release
Effects of infections due to exotoxin release
Mediator role on sepsis
what is endotoxin release?
LPS needs an LPS-binding protein to bind to macrophages
LTA do not need such proteins
what is exotoxin release?
Pro-inflammatory response
Small amounts of superantigens will cause a large amount of mediators to be secreted: cascade effect
what is the role of mediators in sepsis?
Two types of mediators can be released - Th1, Th2
Pro-inflammatory mediators – causes inflammatory response that characterises sepsis
Compensatory anti-inflammatory reaction – can cause immunoparalysis
why does there need to be a balance between various immune responses?
what are clinical features of sepsis?
sepsis 6?
