chronic inflammation

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Chronic Inflammation M Dr Mohammad Manzoor Mashwani

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  • 1. Chronic InflammationMDr Mohammad Manzoor Mashwani

2. Chronic InflammationChronic inflammation is inflammation of prolonged duration(weeks or months)in whichinflammation, tissue injury, and attempts at repaircoexist, in varying combinations. 3. CAUSES OF CHRONIC INFLAMMATION1.Persistent Infection2. Immune-mediated inflammatory diseases3. Toxic Agents 4. Causes of chronic inflammation Acute inflammation: Progressive: osteomyelitis Recurrent: cholycystitis, gastritis. Primary: (abinitio) abinitio means "from the beginning Contents TB, fungal inf. HSR. Persistent factor : foreign bodies 5. Primary Chronic InflammationIt is the cause of tissue damage in some of the most common and disabling human diseases, such asrheumatoid arthritis, atherosclerosis, tuberculosis,and pulmonary fibrosis.It has also been implicated in the progression ofcancer and in diseases once thought to be purelydegenerative, such as Alzheimer disease. 6. Mechanism of chronic infMacrophages TH ActivationFreeTGF-B EGFradicalsEnzymesCytokines FGE +NOGCSF eFibrosisAngiogenesiss u ge Tis ma daHealingGranulation tissue Dr.yasir 2oo7 7. MORPHOLOGIC FEATURESChronic inflammation is characterized by:1. Infiltration with mononuclear cells, which includemacrophages, lymphocytes, and plasma cells2. Tissue destruction, induced by the persistentoffending agent or by the inflammatory cells3. Attempts at healing by connective tissuereplacement of damaged tissue, accomplished byproliferation of small blood vessels (angiogenesis)and, in particular, fibrosis. 8. A, Chronic inflammation in the lung, showing all three characteristichistologic features: (1) collection of chronic inflammatory cells (*), (2)destruction of parenchyma (normal alveoli are replaced by spaceslined by cuboidal epithelium, arrowheads), and (3) replacement by 9. The roles of activated macrophages in chronic inflammation. Macrophages are activated bynonimmunologic stimuli such as endotoxin or by cytokines from immune-activated T cells(particularly IFN-). The products made by activated macrophages that cause tissue injury andfibrosis are indicated. AA, arachidonic acid; PDGF, platelet-derived growth factor; FGF,fibroblast growth factor; TGF, transforming growth factor . 10. GRANULOMATOUS INFLAMMATIONGranulomatous inflammation is a distinctive patternof chronic inflammation that is encountered in alimited number of infectious and somenoninfectious conditions. Immune reactions areusually involved in the development ofgranulomas.A granuloma is a cellular attempt to contain anoffending agent that is difficult to eradicate.In this attempt there is often strong activation of Tlymphocytes leading to macrophage activation,which can cause injury to normal tissues. 11. A granuloma is a focus of chronic inflammation consisting ofa microscopic aggregation of macrophagesthat are transformed into epithelium-like cells, surrounded by a collar ofmononuclear leukocytes, principallylymphocytes and occasionallyplasma cells. 12. Giant CellsOlder granulomas develop an enclosing rim offibroblasts and connective tissue.Frequently, epithelioid cells fuse to form giant cellsin the periphery or sometimes in the center ofgranulomas.These giant cells may attain diameters of 40 to 50m. They have a large mass of cytoplasmcontaining 20 or more small nuclei arranged eitherperipherally (Langhans-type giant cell) orhaphazardly (foreign bodytype giant cell). 13. Types of GranulomasI. Foreign body granulomasII. Immune granulomas 14. Foreign body granulomasIncited by relatively inert foreign bodies.Typically, foreign body granulomas form aroundmaterial that are large enough to precludephagocytosis by a single macrophage and do notincite any specific inflammatory or immuneresponse.The foreign material can usually be identified in thecenter of the granuloma, particularly if viewedwith polarized light, in which it appears refractile. 15. Immune granulomasCaused by agents that are capable of inducing an immune response which produces granulomas usually when the inciting agent is poorly degradable or particulate. 16. Methods of identification of Specific etiologic agent in Granulomatous diseases1. Special stains for organisms (e.g., acid-fast stains for tubercle bacilli), 2. Culturemethods(e.g., in tuberculosis and fungal diseases),3. Molecular techniques(e.g., the polymerase chain reaction in tuberculosis),4. Serologic studies(e.g., in syphilis).