Pathogens VI- Sepsis Flashcards
1- What happens when there is a localised infection?
2- Compare the basic effect for an intracellular/extracellular infection?
3- How do Pathogenic organisms resist innate immunity?
1- Localised response (NOT SEPSIS)
2-
EX: - More inflammation - Lots of neutrophils
IN: - Limited inflammation - NK cells present - Few neutrophils
3- Virulence factors
If controls don’t work for local infections as pathogens resists innate immunity, what is needed?
- More robust response required
-> To clear pathogen
NOT SEPSIS
What symptoms arise due to local infections?
What can a suppressed immune system lead to? (5)
1- Neutropaenia: Neutropaenic sepsis
2- Better environment for organisms: Mucus layer in COPD/CF + Glucose secretion in diabetes
3- Hypo-responsive immunity - Measles virus suppression of TH1 responses
4- Reactivation of dormant organisms
- Latent TB infection
- Shingles
5- Access to deeper tissues
- Ventilator-associated pneumonia
- Catheter-associated UTI
Which organisms take advantage of a weakened immune system?(4)
Staphylococcus epidermidis,
Pseudomonas aeruginosa,
Viridans group streptococci,
Klebsiella pneumoniae
1- Symptoms and signs of infection are a product of what? What does this mean?
2- Relate this to what would happen with a weakened immune system.
- Inflammatory response > So limited immune response will produce less of these symptoms
->Neutropaenic sepsis
2- Weakened immune system = less of an inflammatory response = produce less symptoms, no matter how bad the infection is.
> Someone = seriously ill but not show the signs
What happens when the infectious agent reaches the bloodstream?
(What do PBMCs do?)
- Infection cannot be contained at the primary site and begins to spread, often to the bloodstream. > SYSTEMIC INFLAMMATORY RESPONSE SYNDROME =
Activation of peripheral blood mononuclear cells (monocytes) + Large amount of pro-inflammatory immune products at the primary site leads to systemic signs of infection.
- Fever
- HR
- CRP level raised
- WCC raised
When does Systemic inflammatory response syndrome SIRS become Sepsis?
- SIRS response to infection begins to lead to non-perfusion of organs (by vasodilatation associated with severe non-localised oedema, reduced blood pressure and hyper- coagulation) and then these begin to fail.
> So, sepsis is linked to organ failure (and vice-versa)
What do You need to remember when it comes to sepsis ans SIRS?
- Aren’t “diseases” > manifestations of a primary condition that is not being controlled > look for the underlying cause!
e.g. Sepsis secondary to cellulitis manage 2g IV flucoxacillin
PBMC-derived TNFα results a feedback-loop of…
- Tissue-factor expression, neutrophil activation and NO production
How can sepsis lead to septic shock?
- Spread of pro-inflammatory material is incredibly high and oxygen demand by tissues is excessive, it can lead to decompensation(failure of multiple organ systems)
> Sepsis gets so severe that your body’s response to infection starts harming you more than the infection itself.
In septic shock Low BP/MAP is compensated by what?
- Constriction of blood vessels and increased heart rate/force-of-contraction
Poor perfusion of organs and loss of central blood-pressure regulation are severe what happens if ongoing severe immune responses continue?
- Depletion of a patients WBCs/ proteins/ molecules and activation of anti-inflammatory mechanisms
- As immune response is causing patients symptoms depletion of immune cells alleviates the symptoms from the immune response, even though the patient is still very ill.
COMPENSATORY ANTI-INFLAMMATORY RESPONSE SYNDROME
How can sepsis lead to compensatory anti inflammatory response syndrome?
What does sepsis often result from? What primary condition?
- Pulmonary infection (but can be anywhere)
SEPSIS Acronym
What is the criteria to be diagnosed with SIRS?
- SIRS = A body-wide response involving inflammatory mediators – not always caused by infection
> SIRS defined as two or more these in the same patient
There are concerns that focus on organ dysfunction may delay spotting some cases
UHNM implements the “flag” system to assess unwell patients: Produced by the UK Sepsis Trust
When do we think sepsis if an individual has suspected infection for patient with SIRS?
Basics of diagnosis:
How can we confirm inflammatory and organ function variables to get a SOFA score?
- White cell count
- CRP
What is the sepsis 6?
- Completing these simple steps inside one hour will double the patient’s chances of survival
Conclusion
