Sepsis and Septic Shock Flashcards
What is sepsis?
Life-threatening organ dysfunction caused by dysregulated host response to infection
What is septic shock?
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
What are the body’s defences against sepsis?
Physical barrier
Innate immune system
Adaptive immune system
Physical barrier
Skin
Mucosa
Epithelial lining
Innate immune system
IgA in gastrointestinal tract
Dendritic cells/macrophages
Adaptive immune system
Lymphocytes
Immunoglobulins
Pathophysiology of sepsis
Uncontrolled inflammatory response
Features consistent with immunosuppression
Probable change of the sepsis syndrome over time
Features of immunosuppression
Loss of delayed hypersensitivity
Inability to clear infection
Predisposition to nosocomial infection
Change in sepsis 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 the three phases in the pathogenesis of sepsis?
Release of bacterial toxins
Release of mediators
Effects of specific excessive mediators
Gram negative commonly released toxins
Lipopolysaccharide
Gram positive commonly released toxins
Microbial-associated molecular pattern
Superantigens
Superantigens
Staphylococcal toxic shock syndrome toxin (TSST)
Streptococcal exotoxins
Microbial-associated molecular pattern (MAMP)
Lipoteichoic acid
Muramyl dipeptides
What are the sepsis 6?
Take 3, give 3 Blood cultures Blood lactate Measure urine output Oxygen sats aim 94-98% IV antibiotics IV fluid challenge
When to consider HDU referral
Low BP responsive to fluids Lactate >2 despite fluid resuscitation Elevated creatinine Oliguria Liver dysfunction, Bil, PT, Plt Bilateral infiltrates, hypoxaemia
When to consider ITU
Septic shock
Multi-organ failure
Requires sedation, intubation and ventilation
General features of sepsis
Fever >38oC – presenting as chills, rigors, flushes, cold sweats, night sweats, etc
Hypothermia <36oC – especially in the elderly and very young children (remember the immunosuppressed)
Tachycardia >90 beats/min
Tachypnoea >20 /min
Altered mental status – especially in the elderly
Hyperglycaemia >8mmol/l in the absence of diabetes
Inflammatory variables in sepsis
Leucocytosis Leucopenia Normal WCC with greater than 10% immature forms High CRP High procalcitonin
Tissue perfusion variables in sepsis
High lactate
Skin mottling and reduced capillary perfusion
Effects of infections due to endotoxin release
LPS needs an LPS-binding protein to bind to macrophages
LTA do not need such proteins
Effects of infections due to exotoxin release
Pro-inflammatory response
Small amounts of superantigens will cause a large amount of mediators to be secreted: cascade effect
Mediator role in sepsis
Pro-inflammatory mediators
Compensatory anti-inflammatory reaction
Pro-inflammatory mediators
Causes inflammatory response that characterises sepsis
