Rheumatoid Arthritis

Question 1

rheumatoid arthritis

Answer 1

• joint disease affecting 1-2% of the population
• 80% of people with RA are women (autoimmune?)
• systemic and affects CT all throughout the body
• affects non-wt bearing joints (distal joints like fingers, toes, ankles)

Question 2

etiology

Answer 2

• complex trait -> genetic and environmental triggers
• bacterial or viral triggers (ex. EBV)
• autoimmune (HLA and MHC gene mutations)

Question 3

patho

Answer 3

• combination of B cells and T cells
• T helper cells are activated (by interacting with Ag-presenting cells when infected with the bacterial or viral trigger) and release mediators/cytokines (eg. TNF, IL-1) that induce inflmtn and communicate damage within the joint
• T helper cells activate T cells -> target synovial membrane -> inflmtry damage within joint cavity
• T helper cells activate B cells (now plasma cells) that prod. a specific Ab that targets the joint, known as RF (rheumatoid factor) -> not all pts w/ RA are (+) for this Ab
• immune complex HS (Type III)
• repeated autoimmunity and hypersensitivity -> ongoing inflmtn -> complement activated (increased inflmtn and WBC attraction) -> continuous damage = obvious joint damage
• T cells and Abs target synovial membrane, but inflmtry damage that follows affects the membrane, cartilage and underlying bone once cartilage is damaged
• calcification -> damaged bone will release Ca+ which deposits within the joint
• joint fusion -> difficult to mobilize joint d/t extensive damage (aka fused)
• as disease progresses, ligaments change their alignment -> alters how bones are attached to bones

Question 4

TNF

Answer 4

• tumor necrosis factor

- cytokine that can cause cell death, cachexia (muscle wasting) and fever by stimulating IL-1 secretion

Question 5

Interleukin-1

Answer 5

a pro-inflammatory cytokine that increases WBC migration to the site, induces fever (endogenous pyrogen) and causes hyperalgesia (increased sensitivity to pain)

Question 6

pannus

Answer 6

granulation tissue that develops within the joints

• angiogenesis in synovium
• contains inflmtry cells which release proteases that further tissue damage
• proteases target articular cartilage
• space-occupying within small joints ->less room = decreased mobility

Question 7

manifestations

Answer 7

• early-age onset (20s-30s)
• non-specific mnftns at beginning of disease: fatigue, generalized pain, malaise (subtle onset)
• later on, fatigue intensifies, stiffness after inactivity,