Difference between revisions of "Rheumatoid Arthritis"

Revision as of 19:09, 28 November 2010

Rheumatoid Arthritis-Brian Catchpole RVC 2008

Pathogenesis:

Type IV hypersensitivity: CD4 Th-1 cell mediated.
Macrophages phagocytose self antigens and can present peptides on their MHC Class II molecules. The autoreactive TH-1 cells release IFN-gamma which activates macrophages to release prostaglandins, MMP enzymes and TNF-alpha (pro-inflammatory mediator), see diagram. These cytokines cause inflammation and tissue destruction.

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 * [[Type IV Hypersensitivity|Type IV hypersensitivity]]: CD4 Th-1 cell mediated.
 * Macrophages phagocytose self antigens and can present peptides on their MHC Class II molecules. The autoreactive TH-1 cells release IFN-gamma which activates macrophages to release prostaglandins, MMP enzymes and TNF-alpha (pro-inflammatory mediator), see diagram. These cytokines cause inflammation and tissue destruction.
-*Occurs in the dog, mainly smaller breeds
-*Uncommon
-*Progressive erosive polyarthritis
-*Mostly involves elbows, stifles, carpal and tarsal joints
-*Grossly:
-**Marked villus hypertrophy of synovial membrane
-**Cartilage erosion
-**[[Musculoskeletal Terminology - Pathology|Pannus and periarticular osteophyte]] formation
-**In severe cases ankylosis
-*Histologically:
-**Hyperplasia of lining cells
-**Proliferative synovitis
-**Synovial membrane has fibrin deposits
-**Lymphoid and plasma cell infiltration
-**Surrounding haemorrhagic areas
-**Macrophages containing [[Pigmentation - Pathology#Haemosiderin|haemosiderin]]
-**Connective tissue may contain foci of necrosis
-**Areas of erosion of peripheral articular cartilage and underlying subchondral bone
-*Pathogenesis:
-**May involve deposition of immune complexes within joints
-**Substances degrading cartilage are released by synovial cells and macrophages involved in pannus formation
 [[Category:Cell Mediated Autoimmune Diseases]][[Category:To Do - Clinical]][[Category:To Do - Blood]]