91: Sepsis and Septic Shock COPY Flashcards
What is the incidence and mortality rate of sepsis in veterinary medicine?
- the incidence rate is not established
- mortality ranges from 20-68%
What is the definition of Bacteremia?
presence of live bacterial organisms in the bloodstream
What is the definition of sepsis?
clinical syndrome caused by infection and the host’s systemic inflammatory response to it
can be bacterial, viral, protozoal, or fungal in origin
What is the definition of septic shock?
Acute circulatory failure and persistent arterial hypotension despite volume resuscitation, associated with sepsis
what is the arterial blood pressure cutoff for the definition of septic shock in veterinary and human patients?
the critical BP cutoff is not established in veterinary patients, but extrapolated from the human consensus:
- In people, hypotension is defined by a systolic arterial pressure less than 90 mm Hg, a mean arterial pressure less than 60,
- or a reduction in systolic pressure of greater than 40 mm Hg from baseline despite adequate volume resuscitation, in the absence of other causes of hypotension.
what is the definition of Systemic inflammatory response syndrome (SIRS)?
The clinical signs of systemic inflammation in response to infectious or noninfectious insults (e.g., trauma, pancreatitis, burns, snakebites, neoplasia, and heat stroke).
what is the definition of multiple organ dysfunction syndrome (MODS)?
Physiologic derangements of the endothelial, cardiopulmonary, renal, nervous, endocrine, and gastrointestinal (GI) systems associated with the progression of uncontrolled systemic inflammation and disseminated intravascular coagulation (DIC).
- two or more organs affected
What are the 4 hallmarks of sepsis
- Dysregulation of vasomotor tone
- Increased vascular permeability
- Dysfunctional microcirculation
- Coagulation abnormalities
What is PIRO?
a concept to stage sepsis, adopted after the 2001 international sepsis definition conference
to describe clinical manifestation of the infection and the host response to it
Predisposition, Insult or Infection, Response, Organ dysfunction
not yet adapted in vet med due to lack of advanced diagnostic techniques
What is the most common orignin of gram negative sepsis in cats and dogs?
gastrointestinal and genitourinary systems
What is the most common origin of gram positive sepsis in dogs and cats?
skins, injured soft tissue, IV catheters
What is the most important pathogen-associated molecular pattern of gram negative bacteria?
Explain how it leads to inflammation and what receptors/cytokines/cells are involved in this pathway
Lipopolysaccharide (LPS) > part of the gram-negative bacterial cell wall
- binds to lipololysacchardie binding protein (LBP) > forms LPS-LBP complex
- LPS-LBP complex binds to macrophage membrane-bound CD14
- macrophage activation > Toll-like receptors > signaling transfuction to the nucleus > starts transcription of inflammatory cytokines
inflammatory cytokines:
- tumor necrosis factor-alpha (TNF-alpha)
- IL-1, IL-6, IL-8
- interferon gamma
What does CARS stand for? List 3 of its cytokines.
compensatory anti-inflammatory response syndrome > counter-inflammatory mediators to reduce inflammatory response
IL-4, IL-10, IL-13
What are the most important pathogen-associated molecular patterns (PAMPs) of gram positive bacteria?
cell wall components:
- lipoteichoic acid
- peptidoglycan
- peptidoglycan stem peptides
bacterial DNA
exotoxins
why are exotoxins of gram positive bacteria “superantigens”?
soluble bacterial exotoxins induce widespread T cell activation > inflammatory cytokines released:
- interferon gamma
- TNF-alpha
How can neutrophils lead to extensive host tissue damage?
release of:
- ROS
- proteases
- lysozymes
- lactoferrin
- cathepsins
- defensins