ICS Flashcards
2 good scenarios of inflammation, 2 bad scenarios of inflammation
good: infection and injury
bad: autoimmunity (where body starts to attack its own cells and tissues), hypersensitivity
differences between acute and chronic inflammation
Acute:
–Sudden onset
– Short duration
– Usually resolves
Chronic:
– Slow onset or sequel to acute
– Long duration
– May never resolve
5 types of cells involved in inflammation
- Neutrophil polymorphs
- Macrophages
- Lymphocytes
- Endothelial cells
- Fibroblasts
Neutrophil polymorphs
1- lifespan
2- sequence in acute inflammation
3- roles in inflammation
1: short lived (hours)
2: usually first on scene of acute inflammation
3: roles:
- cytoplasmic granules full of enzymes that kill bacteria
- usually die at the scene of inflammation
- release chemicals that attract other inflammatory cells such as macrophages
macrophages
1- lifespan
2- roles in inflammation (4)
1- long lived (weeks to months)
2- phagocytic properties, ingest bacteria/debris may carry debris away, may present antigen to lymphocytes
lymphocytes
1- lifespan
2- roles in inflammation
1- long lived (years)
2- produce chemicals which attract in other inflammatory cells, immunological memory for past infections and antigens
Endothelial cells
1- location
2- 3 roles in inflammation
1- line capillary blood vessels in areas of inflammation
2-
(1) become sticky in areas of inflammation so inflammatory cells adhere to them
(2) become porous to allow inflammatory cells to pass into tissues
(3) grow into areas of damage to form new capillary vessels
Fibroblasts
1- lifespan
2- role in inflammation
1- long lived cells
2- form collagen in areas of chronic inflammation and repair
Acute inflammation example
- cell
- blood vessels
- inflammation of… and effect
- outcomes
Acute appendicitis:
- unknown precipitating factor
- neutrophils appear
- blood vessels dilate
- inflammation of serosal surface occurs, pain felt
- appendix either surgically removed or inflammation resolves or appendix bursts with generalised peritonitis and possible death
Chronic inflammation example
- what doesn’t occur?
- cells involved
- what then occurs?
Tuberculosis
- no initial acute inflammation
- myobacteria ingested by macrophages, which often fail to kill the myobacteria
- lymphoccytes and macrophages appear
- fibrosis occurs
what is a granuloma?
mass of granulation tissue which is usually produced in response to infection/inflammation/ presence of a foreign substance. epithelioid histiocytes
3 steps of acute inflammation
Potential outcomes of acute inflammation
(1) vascular component- dilation of vessels
(2) Fluid Exudative component- vascular leakage of protein-rich fluid due to increased vascular permeability
(3) Cellular exudative component- Neutrophil polymorph is the characteristic cell recruited to the tissue
Outcomes possible; resolution, suppuration (e.g. abcess), organisation or progression to chronic inflammation
6 main causes of acute inflammation
(1) Microbial infections- e.g. pyogenic bacteria, viruses, fungal etc. Bacteria release exotoxins (chemicals synthesised by them that specifically initiate inflammation) or endotoxins (associated with their cell walls). Some microorganisms cause immunologically mediated hypersensitivity reactions e.g. parasitic infections and tuberculosis
(2) Hypersensitivity: inappropriate/excessive immune reaction which damages tissues
(3) Physical agents e.g. trauma, ionising radiation, heat, cold
(4) Chemicals
(5) Bacterial toxins
(6) Tissue necrosis- death of tissues from lack of oxygen/nutrients resulting from inadequate blood flow (infarction) or a potent inflammatory stimulus. Often shows acute inflammatory response (resumably in response to peptides released from the dead tissue)
5 macroscopic appearances of acute inflammation
(1) Rubor (redness)- due to dilation of blood vessels in damaged area
(2) Calor (heat)- temp increase due to hyperaemia and resultant vascular dilation (and also systemic favour)
(3) Tumor (swelling)- result from oedema and physical mass of inflammatory cells migrating into area; progression of inflammation response leads to formation of new connective tissue contributes to the swelling
(4) Dolor (pain)- stretching and distortion of tissues due to inflammatory oedema and pus under pressure in abcess cavity. Also some chemical mediators of inflammation (bradykinin/prostaglandin/serotonin- involved in acute) are known to induce pain
(5) Loss of function
chemical mediators of acute inflammation- effects
(1) injured tissue releases chemical substances following injury into uninjured areas- leads to spread of acute inflammatory response
(2) early in immune response, histamine and thrombin released by original inflammatory stimulus cause up-regulation of adhesion molecules on the surface of endothelial cells. Overall effect of molecules is the firm neutrophil adhesion to the endothelial surface
(3) endogenous chemical mediators cause vasodilation, emigration of neutrophils, chemotaxis, increased vascular permeability, itching and pain
Plasma enzymatic cascade systems
(1) complement
(2) kinin
(3) Coagulation
(4) Fibrinolytic
what is the best known chemical mediator in acute inflammation?
Histamine
list 3 medications for inflammation
- Aspirin
- Ibuprofen
- Paracetamol
what do macrophages do?
ingest bacteria n debris
may carry debris away
may present antigen of lymphocytes
what do lymphocytes do?
produce chemicals which attract other inflammatory cells
have an immunological memory for past infections and antigens
where are inflammatory cells?
in bone marrow, released into blood
outcomes of acute inflammation
(1) Resolution
(2) Suppuration- if there is excessive exudate, leads to pus production
(3) organisation (due to exessive necrosis or suppuration)
(4) Progression to chronic inflammation
Systemic effects of inflammation
- pyrexia
- constitutional symptoms
- weight loss
- reactive hyperplasia of the reticuloendothelial system (the enlargement of an organ or tissue caused by an increase in the reproduction rate of its cells,)
- heamatological changes
- amyloidosis (abnormal protein produced in bone marrow builds up in organs and can be deposited in any tissue or organ)
causes of chronic inflammation (4)
(1) primary chronic inflammation
(2) transplant rejection
(3) Progression from acute inflammation
(4) recurrent episodes of acute inflammation