Sepsis Flashcards
(36 cards)
What is sepsis?
Life-threatening organ dysfunction due to a dysregulated overwhelming immune host response to infection
Triggered by infection in susceptible patients (can not occur in the absence of infection)
What tool is used to identify high risk patients and what is the critera?
qSOFA
Respiratory ≥ 22 breaths/min
Altered mentation (Glasgow Coma Scale <15)
Systolic blood pressure ≤ 100 mm Hg
What is the baseline for qSOFA?
Baseline qSOFA = 0 unless patient has pre-existing organ dysfunction BEFORE onset of infection
What is an important critera to aid diagnosis of infection (not specific to sepsis) and what does it measure?
SIRS
SIRS refers to the body’s inflammatory response to a non-specific insult, which can be either infectious or non-infectious in origin
What does the GCS assess?
What is the threshold?
mentation
<15 for altered mentation
What causes sepsis?
any infection (bacterial, viral, fungal) can trigger sepsis
Where is the most common site of infection?
lungs
What type of bacteria triggers sepsis the most?
gram negative bacteria (E-coli, p.gingivalis)
(LPS toxin)
Who gets sepsis most?
Sepsis disproportionately affects medically and immune- compromised patients
* Cancer
* Cirrhosis
* Autoimmunity
* HIV/AIDS
* Organ transplantation
* Diabetes
What system activations is the immunopathogenesis of sepsis associated with?
- Innate immunity
- Complement system
- Vascular endothelium
- Coagulation System
- Adaptive Immunity
Excessive inflammation and immune suppression
What is the pathophysiology of sepsis?
- Body-wide blood clotting and ‘leaky vessels’
- Organ failure
- Hypotension
What receptors activate inflammatory signaling pathways in sepsis and how?
Pattern Recognition Receptors (PRRs)
recognise
Pathogen-Associated Molecular Patterns (PAMPs)
Damage-Associated Molecular Patterns (DAMPs)
Examples of PAMPS VS DAMPS
what are examples?
PAMPS
Exogenous (non-self) factors expressed by pathogens
(LPS, peptidoglycan, nucleic acids)
DAMPS
Endogenous (host) factors released following cell damage
(Heat-shock proteins, nucleic acid)
What does TNFalpha do when released systemically?
TNF⍺ coordinates local containment of infection but drives sepsis when released systemically
Systemic vasodilation
Increased vascular permeability
Loss of blood pressure
Systemic blood clotting in the microvasculature
What does TNFalpha stimulates expression of in controlling local infections?
- Adhesion molecules on endothelial cells
- Proteins that trigger blood clotting
- Recruits immune cells to site of infection
- Prevents pathogen spreading via blood
What system is a hallmark of sepsis?
complement
How is the complement system activated and what does it generate?
Activated immediately upon recognition of PAMPs and DAMPs
Generation of peptides C3a and C5a
What does C5a do?
- C5a drives immunopathogenesis
- Potent chemoattractant
- Further amplifies inflammation
- Contributes to vasodilation, tissue damage and organ failure
What happens in the endothelial barrier during sepsis?
dysfunction
Changes in the vascular endothelium in response to inflammatory stimuli during sepsis
What state does sepsis result in?
hypercoagulative state
What is the hypercoagulative state characterised by?
- Microvascular thrombi
- Fibrin deposition
- Neutrophil extracellular trap
formation - Endothelial injury
What organ systems does sepsis usually affect and what are the common signs?
- Neurological (altered mental status)
- Pulmonary (hypoxaemia) – Acute Respiratory Distress Syndrome (ARDs)
- Cardiovascular (shock)
- Renal (oligouria)
As well as excessive inflammation, what do patients with sepsis show?
immune supression
How is innate immunity activated?
via PAMPs and DAMPs
