Arthritis Flashcards
Aetiology of acute septic
Staph aureus mainly and less frequently strept
Source of infection
Direct
Following penetrating injury
By blood
Pathology of acute septic
Characteristized by pain tenderness redness swelling and warmth , marked restrictions of movements and purulent fluid exudate fills the joint space are present , destruction of articular cartilage may occur followed by joint ankylosis
Def of rheumatoid arthritis
Chronic multisystem disease with stmetric inflammation of small joints, extra articular manifestations are common
Aetiology of RA
it is a member of collagen diseases , the current theory that it occurs in imunogentically predisposed person due to microbial agent as a trigger antigen
Incidence of RA
Peak incidence occurs in middle age with predominance of females
Pathology of RA
Symmetric inflammation of small joints especially PIP ( swan neck deformity) wrist ( radial deviation) and elbow and knee is also characteristic
Microscopic picture of RA
Articular lesions
1- prolefritive synovitis forming large villi of synovium
2- formation of pannus ( special type of granulation tissue ) what makes this disease aggressive
3- thickening of synovial membrane due to oedema congestion and multilayering of synoviocytes
4- infiltration of synovial membrane by chronic inflammatory cells especially lymphocytes and plasma cells and macrophages that lead to forming lymphoid follicle
5- foci of fibrinoid necrosis
Extra articular lesions : non specific inflammatory manifestations in blood vessels in pleura or lung but there is characteristic subcutaneous rheumatoid nodules in over pressure points as knee and sacrum
Def of osteoarthritis
The most common chronic disease of synovial joint, it is characteristized by degeneration of articular cartilage over years
Names of osteoarthritis
Osteoarthrosis
DJD ( degenerative joint disease)
Common sites of osteoarthritis
Weight bearing joints and spine
Types of osteoarthritis
Primary: in old people as a result of tear and wear of the joint
Secondary: in old or young people due to
1- chronic stress on joint as in obesity
2- abnormal joint mechanics : in cases of defective nerve supply to a joint as in ( charcot joint ) and in cases of spinal cord lesions ( tabes dorsalis of syphilis )
3- traumatic injury in articular cartilage due to fracture or repair of repeated minor trauma
Pathology of osteoarthritis
1- degeneration and softening of the central part
2- the bones look like polished ivory
3- death of osteocytes and increased osteoclastic activity forming rarefactions and microcyst formation and micro fractures
4- proliferation of the peripheral part leading to forming of cartilaginous lipping
5- ossification of cartilaginous lipping forming boney projections ( osteophytes )
6- fracture of these osteophytes forming intra articular loose bodies
7- mild chronic inflammation in synovial membrane and osteocartilgineous metaplasia