New MSK Pathology Lectures Flashcards
What is the most common form of joint disease?
Osteoarthritis
What are some features of osteoarthritis?
Degenerative changes in the articular cartilage, structural changes, functional impairment, related to aging and biomechanical stress, aches and pains worse with use
What are the two kinds of osteoarthritis?
Primary = insidious, no overt cause, age related (>50) Secondary = predisposing condition, excess/inappropriate weight bearing, deformity, injury, systemic disease, age <50
What joints are normally spared from osteoarthritis?
Wrists, elbows and shoulders
What are the early events of osteoarthritis pathogenesis?
Injury to chondrocytes and matrix, chondrocytes proliferate = release inflammatory mediators, proteases, collagen and proteoglycans, remodelling and degradation of cartilage
What are the late events of osteoarthritis pathogenesis?
Inflammatory changes in synovium and subchondral bone, repetitive injury and chronic inflammation causes loss of chondrocytes, disruption to and loss of cartilage matrix
What are the early pathological changes in osteoarthritis?
Damage to cartilage, clusters of chondrocytes, small fissures in cartilage, fibrillation
What are the later pathological changes in osteoarthritis?
Cartilage is completely worn away, subchondral cysts, eburnation, remodelling, osteophyte formation
What is rheumatoid arthritis?
Chronic autoimmune inflammation, systemic and presents with features of arthritis
What are some features of rheumatoid arthritis?
More common in 20-40 year olds, 3:1 female to male ratio, vague systemic features of malaise and fever, generalised MSK pain
How does rheumatoid arthritis affect the joints?
Symmetrical joint involvement, swollen, warm, painful, limited movement in morning and after inactivity, affects small joints before large joints, typically hands, feet, wrists, ankles, elbows, knees and cervical spine, usually spares hips and lumbosacral joints
What is the progression of rheumatoid arthritis?
Joint swelling, decreased ROM, joint fusion
Associated involvement of tendons and ligaments, synovial herniation (cysts)
Joint effusions, peri-articular bone loss, loss of articular cartilage
What is ankylosis?
Joint fusion
What is the acute presentation of rheumatoid arthritis?
Severe symptoms and polyarticular disease, occurs in 10% of patients
What alleles are linked to rheumatoid arthritis?
HLA DRB1 alleles = common structure in beta chain (shared epitope), creates site for binding arthritogens and initiates autoimmune inflammation
What are some environmental factors linked to rheumatoid arthritis?
Infection and smoking
What are some features of the immunology of rheumatoid arthritis?
Cytokine production due to initiation of inflammation
IFNg activates macrophages and synovial cells
IL-17 recruits neutrophils and monocytes
TNF and IL-1 stimulate production of proteases from synovium
RANKL expressed on activated T cells stimulates bone resorption
What are some skin features of rheumatoid arthritis?
Rheumatoid nodules, small vessel vasculitis, pyoderma gangrenosum, associated with episcleritis, pleural and pericardial effusions
What are some features of rheumatoid nodules?
Occur in 25% off patients, often severe disease, pressure points, internal organs involved, necrotising granuloma
What are some features of necrotising granulomas?
Central area of collagen, surrounding palisade of macrophages
What are some manifestations of small vessel vasculitis?
Splinter haemorrhages, peri-ungual infarcts, ulcers, gangrene
What are some ocular and oral manifestations of rheumatoid arthritis?
Ocular = keratoconjunctivitis, episcleritis, scleritis Oral = salivary gland swelling, Sjogren's syndrome
What are some GI and renal manifestations of rheumatoid arthritis?
GI = mesenteric vasculitis (rare), related to medication Renal = forms of glomerulonephritis, amyloid disease