test 9 part 2 Flashcards
Non-specific inflammation
- Response to cut is the same as a burn/ radiation/ infection, etc.
4 signs of inflammation
- Redness
- Pain
- Heat
- Swelling - Goal to dispose of microbes/ toxins / foreign materials
- prevents spread
- prepare for repair
Stages of inflammation
- Vasodilation
- Increase permeability of blood vessels (fluid moves out = edema) - Emigration
- Movement of phagocytes from blood to interstitial fluid (neutrophiles and macrophages that gobble them up) - Tissue repair
components of inflammation and duration
- vascular reaction
- cellular reaction
- acute
- rapid onset / short duration / emigration of neutrophils - chronic
- long duration / lymphocyte involvement / proliferation of blood vessels / tissue necrosis
Major players in inflammation
- circulating white cells (neutrophils / monocytes / eosinophils)
- connective tissue cells (mast cells)
- extracellular matrix (structural fibrous protein)
Inflammation mediated by variety of
- chemical mediators
- derived from plasma proteins and/or cells
Chemical Mediators
- Originate from plasma or cells
- Usually bind to specific receptors on target cells
- One mediator may stimulate the release of other mediators
- Mediators can act on more than one target
- Once activated and released, most are short lived
- Most have the potential to cause GREAT HARM
Chemical mediators that cause vasodilation
- Nitric Oxide
- Histamine (from mast cells, basophils, and platelets)
Chemical mediators that increase vascular permeability
- C3a and C5a
- Bradykinin
- Leukotrienes
Chemical mediators that cause chemotaxis, leukocyte recruitment and activation
- C5a
- Leukotriene B4
- Chemokines
- Interleuken-1
Chemical mediators that cause fever
- Interleuken-1
purpose of Vascular change
- Maximize movement of plasma proteins and appropriate circulating cells into the site of injury or infection
- vasodilation and increase capillary permeability
Vasodilation
- Early manifestation
- Arterioles involved first, followed by opening of new capillary beds
- Induced by variety of mediators (histamine / nitric oxide)
- Allows more blood into an area
- Helps remove microbial toxins and dead cells
- Result: Increased blood flow which increases REDNESS and WARMTH of tissue
increased capillary permeability
- Allows antibodies and clotting factors to leave the blood
Vasodilation and increased
permeability: Histamine
- Mast cells in the tissues release
- Basophils and platelets stimulate the release of histamine in the blood
- Causes increased dilation and permeability
Vasodilation and increased
permeability: Kinins
- Polypeptides
- Induce vasodilation and increase permeability
- Act as chemotaxic agent for phagocytes
- Ex: bradykinin
Vasodilation and increased
permeability: Prostaglandins
- Lipid
- Released by damaged cells
- Stimulate emigration of phagocytes
Vasodilation and increased
permeability: Leukotrienes
- Basophils and mast cells produce
- Increase permeability
Vasodilation and increased
permeability: Complement
- Stimulate histamine release
- Attract neutrophils
- Promote Phagocytosis
Clotting and inflammation
- Clotting factors move into tissues
- Initiate the clotting cascade
- Fibrinogen converted to fibrin
- Localizes and traps invading organisms
- Blocks spread of organism - Within 1hour of start of inflammatory process
Neutrophils and Inflammation
- Neutrophils (first to respond) stick to blood vessel wall with increased blood flow
- Squeeze through blood vessel wall to tissues (emigration) - Neutrophils attempt to destroy via phagocytosis
- Monocytes follow neutrophils
- Transform into macrophages
- Macrophages die (pus)
Extravasation
- movement of leukocytes from vessel lumen to interstitial space
Cellular Events
- Margination: movement of leukocytes toward the wall of the capillary
- Rolling: leukocytes tumble slowly along endothelium, adhere transiently, then are finally attached – endothelium completely lined with white cells
- Transmigration (diapedesis): insert pseudopods into junctions between endothelial cells – move through the junction
- Chemotaxis: migrate thru interstitial fluid to source of problem
4 characteristics of inflammation
- Heat
- Redness
- Large amount of blood in damaged area
- Local temperatures increase
- Metabolic reactions speed up
- More heat released - Swelling
- Increased permeability
- More fluid in the area - Pain
- Symptom of inflammation – neuron injury or increased pressure (edema)
Fever
- Bacteria toxins increase body temperature
- Trigger release of interleukin-1 (cause fever)
- Helps to inhibit the growth of some microbes
- Helps to speed up body reactions
- Aids in repair
2 or more present for diagnosis of Systemic Inflammatory Response (SIRS):
- SIRS – common systemic response to a wide variety of insults
- Body temp above 38C or below 36C
- HR >90 BPM
- Respiratory Rate >20/min
- Or PaCO2 <32mmHg - Leukocyte count >12,000 cell/mm2
Systemic Inflammatory Response After Bypass (SIRAB) injuries
- CPB produces “whole body” inflammatory response - Wide spectrum of injuries -Pulmonary -Renal -Gut -Central Nervous system -Myocardial dysfunction -Coagulopathy -Hemolysis -Fever -Increase susceptibility to infection -Leukocytosis - All come within the “catch-all” terms of SIRS
SIRAB risk factor
- Risk factor – Length of CPB
- Frequently a risk factor, but not necessarily
Common causes of SIRAB
- Set in motion cytokine mediated events that activate vascular endothelium
- Most common culprit = contact with foreign surface
- Altered arterial blood flow patterns
- Sheer stress (blood pumps)
- Cardiotomy suction
- Tissue ischemia
- Reperfusion
- Hypothermia
- Relative anemia
- anticoagulants
Contact activation end result
- Activation of contact proteins
- Coagulation factors XII and XI
- Prekallikrein
- High molecular weight kininogen - End Result
- Formation of bradykinin
- Conversion of plasminogen into plasmin
- Initiates fibrinolysis
- Triggers classical complement cascade.
Generalized big pictures with CPB and inflammation
- Multiple inflammatory mediators are released upon exposure to ECC
- Disrupt homeostasis
- Generalized whole body inflammatory response
- Activates vascular endothelium
- Further neutrophil-mediated injury (tissue damage) - None occur alone
- Stimulate or catalyze other reactions in cycle of SIRAB
Immune system and bypass
- Post operatively –
- Shown patients more susceptible to infections - Noted serum immunoglobulins and complement are decreased
- Chemotaxic ability of granulocytes are decreased
- NK cells are decreased
- Number and Function - CD3+ and CD4+ cells are decreased
- CD8+ cells are slightly increased
- Leukocyte number remains low for about 1 week post bypass