Sepsis Flashcards
Incidence and mortality of sepsis
-Global incidence and mortality decreasing
-37,000 in UK- third major killers behind CHD and stroke
Sequence of sepsis
-Infection
-Bacteraemia
-Sepsis
-Septic shock
-Multiple organ dysfunction
-Death
Definition of infection
-Invasion of body tissues by disease causing organisms
Definition of bacteraemia
-Presence of viable bacteria in the blood stream
Definition of SIRS
-Systemic inflammatory response syndrome (2 or more):
=T: >38* or <36*
=HR: >90 bpm
=RR: >20 breaths per minute
=WBC >12,000 cells/ml or <4000 cells/ml
Definition of sepsis
-Life threatening organ dysfunction caused by a dysregulated host response to infection
-Sequential organ-failure assessment score (SOFA):
=Respiration, coagulation, liver, cardiovascular, brain, kidney
=qSOFA: score >2 associated with poor outcomes (RR >22, confusion, systolic BP <100 mmHg)
Definition of septic shock
-Subset of sepsis in which circulatory, cellular and metabolic abnormalities are associated with a greater risk of mortality
-Clinically identified by a vasopressor requirement to maintain a mean arterial pressure >65 mmHg and a serum lactate >2mmol/L despite of adequate fluid resuscitation
Risk factors for sepsis
-Age
-Bacteraemia
-ICU admission (invasive devices, ventilation)
-Immunosuppression
-Diabetes and obesity
-Cancer
-CAP
-Previous admissions
-Genetic factors (antibody production, lack of T cells, NK cells, complement)
Epidemiology of sepsis
-Extremes of age
-Less than 1 year and elderly
-Risk increases around middle ages and beyond
-Incidence in hospitalised 0.3% septic shock, 57% lung
-Gram positive 36%
-Up to a third organism not found
What are PAMPs
-Pathogen associated molecular pattern (PAMPs)
=Specific to a micro-organism
=Essential for surviving and pathogenicity
=Molecular signature for pathogens
-Gram negative= LPS
-Gram positive= peptidoglycan- lipoteichoic acid
-Yeast= mannan
-Virus= double stranded RNA
-Mycobacteria= mycolic acid
-Recognised by pattern-recognition receptors (toll-like receptors, NOD and C-type lectin receptors)
What is the innate immune response?
-First defence system against pathogens
=Complement (activates cytokine expression, opsonize organism)
=Coagulation (trap with nets)
=Phagocytosis (lyse organism)
=Cytokine expression (signals type and magnitude infection)
=Myelopoiesis (stimuli of bone marrow to produce immune cells)
Pathogenesis of sepsis
-Antigen-presenting cells find organism
-Por-inflammatory repsonse
-Cytokines released
-Increased vascular permeability
-Hyperactive immune response
=increased sequestration of fluid
=organ failure
=immune paralysis
Consequences of sepsis
-Multiple organ failure
=CV, liver, renal, neuro, resp, haem
-Gut-microbiome
=toxic mediators released from injured gut mucosa are transported and could contribute to dysfunction in other organs
-Endocrinopathy
=Release ACTH- high concentration of cortisol
=High levels of catecholamines
=Insulin resistance
-Neuropathy
=Sepsis associated encephalopathy
Symptoms and signs of septic shock
-Hypotension
-Tachycardia
-Peripheral hypoperfusion: cold skin/ cyanosis/ skin blotch
-Purpura
-High RR (hypoxaemia)
-Oliguria
-Altered consciousness
-Fever
-Hypothermia
-Elevated WBC count/ low WBC count
-Low platelet count
Fundamentals of sepsis treatment (Sepsis 6)
-To be delivered with 1hr
- Deliver high-flow oxygen
- Take blood cultures and other cultures, consider source control
- Administer empirical IV antibiotics
- Measure serum lactate or alternative
- Start IV fluid resuscitation using Hartmann’s or equivalent
- Commence accurate urine output measurement
