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| | ==Types== | | ==Types== |
| − | ===Granulomatous Inflammation=== | + | ===[[Granulomatous Inflammation]]=== |
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| − | * Granulomatous inflammation is usually caused by organisms of low virulence but great persistence, or by implanted foreign bodies.
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| − | * Classically appears as a '''granuloma'''.
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| − | ** NOT a tumour, despite the suffix "-oma".
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| − | ** A circumscribed sphere of chronic inflammatory cells enveloped by poorly organised attempts at encapsulation by local connective tissue.
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| − | * The differences between a granuloma and an abscess must be appreciated.
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| − | ** The fibrous envelope is never as well developed as that of an abscess.
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| − | ** The inner contents are never as completely fluid as in an abscess.
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| − | ====Structure of a Granuloma====
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| − | =====Central core=====
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| − | * The central core which contains the agent.
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| − | * The agent may be visible with H&E staining in section, e.g.
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| − | ** ''[[Actinobacillus lignieresii]]''
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| − | *** The cause of "Wooden tongue" in cattle.
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| − | *** Appears as a granule, with a central core of the bacterial colony surrounded by radiating eosinophilic "clubs".
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| − | **** Clubs are considered to be formed from degenerating collagen and antigen-antibody complexes.
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| − | ** ''[[Actinomyces bovis]]''
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| − | *** The cause of "Lumpy Jaw" in cattle.
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| − | *** Forms granules containing bacteria and "clubs".
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| − | ** Fungal hyphae
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| − | ** Parasitic larvae
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| − | ** Foreign bodies
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| − | * The agent might not be visible without being selectively stained.
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| − | ** E.g. [[:Category:Mycobacterium species|''Mycobacterium tuberculosis'']] and ''[[Brucella abortus]]''.
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| − | *** Stain using an acid-fast stain (Ziehl-Neelsen), or a modification.
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| − | *** These organisms are intracellular in the macrophages.
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| − | =====Chronic Inflammatory Cells===== | |
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| − | * Outside the core is a substantial number of chronic inflammatory cells.
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| − | ** Mainly macrophages.
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| − | *** Often appear as epithelioid cells.
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| − | ** Lymphocytes
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| − | ** Plasma cells.
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| − | * Neutrophils and necrotic remnants of cells can be quite prominent in the granulomas of [[:Category:Actinobacillus species|''Actinobacillus'']] and [[:Category:Actinomyces|''Actinomyces'']] species.
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| − | * Eosinophils are prominent in parasitic granulomas.
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| − | * A scattered and variable number of Giant cells are often seen, but not always in every granuloma.
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| − | =====Outer Envelope=====
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| − | * The final layer is an outer envelope of incomplete fibrous tissue.
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| − | * Giant cells can also be seen in this area.
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| − | ====Gross Appearance of Granulomas====
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| − | * The cut surface of granulomas varies considerably;
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| − | ** Tuberculous granulomas tend to have solid whitish cores which are often calcified.
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| − | *** Grate on the knife when cut through.
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| − | ** Parasitic granulomas are often greenish in colour due to the substantial numbers of eosinophils.
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| − | *** Older ones are also often calcified.
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| − | ** [[:Category:Actinobacillus species|''Actinobacillus'']] and [[:Category:Actinomyces|''Actinomyces'']] species often have liquefied cores due to the necrosis and [[Neutrophils|neutrophils]].
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| − | *** I.e. they are purulent.
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| − | *** May discharge to the surface along sinus tracts.
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| − | *** The central core of bacteria and ‘clubs’ may appear as yellowish granules in this pus.
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| − | **** Often called "sulphur granules".
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| | ===Granulation Tissue=== | | ===Granulation Tissue=== |
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| | * Ulcers and open wounds may heal by granulation. | | * Ulcers and open wounds may heal by granulation. |
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| | + | [[Category:Chronic Inflammation]][[Category:To Do - Blood]] |
| | ===Lymphocytic Inflammation=== | | ===Lymphocytic Inflammation=== |
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| | *#** Ee.g. [[:Category:Mycoplasmas|Mycoplasmosis]] in swine and calves. | | *#** Ee.g. [[:Category:Mycoplasmas|Mycoplasmosis]] in swine and calves. |
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| | + | [[Category:Chronic Inflammation]][[Category:To Do - Blood]] |
| | [[Category:Inflammation]] | | [[Category:Inflammation]] |