Chapter 2 - SIRS Flashcards
systemic inflammatory response and failure of multiple organ systems are a
syndrome
What is the Systemic Inflammatory Response?
inappropriate and generalized inflammatory response to stimuli, which may or may not result from an infectious process.
The key event in the initiation and propagation of SIRS is the release of
endogenous molecular substances (Bacteria or their endotoxins, or both)
What is the ultimate goal of the immune system in microbial invasion or tissue damage?
To contain infection, alarm the host, and promote tissue repair
What can initiate Systemic Inflammatory Response Syndrome (SIRS)?
Infection, endotoxemia, severe trauma, ischemia, or hypoxemia
What is the Compensatory Antiinflammatory Response Syndrome (CARS)?
Over-recruitment of antiinflammatory processes leading to anergy
What are cytokines in the context of SIRS?
Protein substances that respond to infectious agents or tissue damage
what are the 2 types of cytokine?
**proinfalmamtory **: tumor necrosis factor (TNF); interleukin 1, 6, and 8 (IL -1, IL -6, and IL -8, respectively); and interferon-γ (IFN-γ)
antiinflammatory ILa4, IL-10, Il-11, IL-13, TGF-β
who produces the proinflammatory cytokines TNF, IL and IFN-γ?
Monocytes and macrophages, neutrophils (TNF), fibroblasts, keratinocytes, lymphocytes (IL-1, IL-6) and natural killer cells (TNF, IFN-γ) endothelial ç are universal sources for the proinflammatory cytokines,
what are the main functions of TNF, IL-1 and IL-6?
initiate coagulation, fibrinolysis, complement activation, the acute phase response, and neutrophil chemotaxis. TNF and IL -1 also induce** pyrogenic** activities
A
rachidonic acid is a 20-carbon fatty acid that is a major constituent of the phospholipids of all cell membranes
What is the role of arachidonic acid in SIRS?
To be a precursor for eicosanoid synthesis
In experimental horses infusion of endotoxin results in
increased circulating levels of TNF and IL -6
in septic foals that did not survive, IL -___ gene expression was significantly greater than in surviving ones
in septic foals that did not survive, IL -10 gene expression was significantly greater than in surviving ones
Endotoxin, TNF, and ILil-1 all upregulate the activity of
phospholipase A2, the enzyme responsible for cleavage of arachidonic acid
Once released, arachidonic acid is further metabolized by either ________________ to form the family of leukotrienes, or __________________, to form the prostanoids: thromboxane A2 (TxA2) and the prostaglandins (PGs).
Once released, arachidonic acid is further metabolized by either lipoxygenase, to form the family of** leukotrienes**, or cyclooxygenase, to form the prostanoids: thromboxane A2 (TxA2) and the prostaglandins (PGs).
The prostanoids are vasoactive substances: TxA2 and PGF2α are potent
The prostanoids are vasoactive substances: TxA2 and PGF2α are potent** vasoconstrictors**
The prostanoids PGI 2 and PGE2 are
PGI 2 and PGE2 are** vasodilators.**
PGE2 has 2 functions name them
**vasodilation and pyrogen
What is the key initiation and propagation of SIRS?
invading microorganism release PAMPs or DAMPs
what does it mean PAMPS and DAMPs
pathogen-associated molecular patterns [PAMPs])
damage-associated molecular patterns [DAMPs]
who recognize the PAMPs and DAMPs and releases endogenous mediators that drive inflammatory response?
Host cell–associated pattern recognition receptors (PRR s)
What is the name of multiple organ dysfunction syndrome?
MODS
Platelet - Activating Factor is released from cell membrane of which ç?
mononuclear phagocytes
endothelial ç
platelets
phospholips by phosphilipase A2
The released **alkyl-lyso-glycerophosphocholine **is then acetylated to form PAF. The biologic effects of PAF include
vasodilation,
increased vascular permeability,
platelet aggregation,
and recruitment
and activation of phagocytes
What does it mean to be acute phase protein?
An acute phase protein is any protein whose blood concentration significantly increases (or decreases) during an inflammatory response
What happens when SIRS and CARS are appropriately balanced?
Homeostasis resumes in the host
What is believed to be responsible for the development of clinical signs and symptoms in systemic inflammatory response?
The phagocytic activation of the monocyte/macrophage cell lineage is thought to be directly responsible.
What is the general accepted summary of conditions leading to systemic inflammatory response?
It’s generally accepted that bacteria or their endotoxins, or both, induce and sustain a marked inflammatory response by the host, leading to fatal outcomes in sensitive organs.
What is Mixed Antiinflammatory Response Syndrome (MARS)?
MARS is a condition where both SIRS and CARS coexist.
where are produced the acute phase proteins?
in liver
Which cytokines are main responsible for transcription of acute proteins?
TNF, IL -1, and IL -6; glucocorticoids; and growth factors stimulate and modulate gene expression
what are the two major acute phase proteins?
SAA and C-reactive protein (CRP)
SAA is involvved in which regulations?
cholesterol regulation
chemotaxis
mediation of inflammatory events
Reference value for healthy neonatal foals and adults, value abnormal
expected SAA concentration in healthy neonatal foals and adult horses is less than 27 mg/L
with values greater than 100 mg/L, suggestive of an infectious process in foal
how do you diagnose the values of SAA
Using the latex agglutination immunoturbidimetric assay
What does C-reactive protein (CRP) do?
CRP can activate complement, induce phagocytosis, and stimulate cytokine and tissue factor expression.
How are acute phase proteins related to the complement system?
They induce bacteriolysis, increase vascular permeability, and enhance opsonization of microbes and damaged host cells.
How do you diagnose the [] of CRP? what is the normal value?
Using radial immunodiffusion, CR P concentrations have been established in healthy foals and adult horses 5 to 14 mg/mL
What is the significance of hyperfibrinogenemia in horses with inflammation?
It is a clinicopathologic finding indicating a response to inflammation.
What is the role of ceruloplasmin and haptoglobin in SIRS?
They bind bacterial nutrient components like copper and iron and neutralize or transport toxic bacterial components.
What happens when SIRS and CARS are appropriately balanced?
Homeostasis resumes in the host.
What do reactive oxygen species commonly originate from?
Mononuclear phagocytes or neutrophils
What are the effects of oxygen free radicals?
They cause molecular damage and induce cytokine production
Which of the following are **vasodilators?
**
a) Angiotensin and endothelin
b) Bradykinin and histamine
c) TxA2 and leukotrienes
d) Complement components
b) Bradykinin and histamine
What is a significant feature of the diagnosis of SIRS?
Specific alterations in heart rate, temperature, and respiratory rate
What triggers the Compensatory Antiinflammatory Response Syndrome (CARS)?
Over-recruitment of antiinflammatory processes
what are the 2 forms of ROS
molecules that contain unpaired electron
hydrogen peroxide (H2O2)
Name the vasoactive mediators
PGs a
NO,
bradykinin = a by-product of activation of the contact coagulation system = VDilator
histamine, =VDilators.
Angiotensin,
endothelin,
TxA2,
leukotrienes (LTC4, -D4, and -E4)
Which values/parameters are measured for dx SIRS?
The diagnosis of SIR S can be made when at least two parameters’ criteria are present
what is the cut value of blood lactate?
2.06 mmol/L
What does Multiple Organ Dysfunction Syndrome (MODS) refer to?
Altered organ function requiring intervention