Rheumatoid Arthritis Flashcards
1
Q
rheumatoid arthritis
A
- 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)
2
Q
etiology
A
- complex trait -> genetic and environmental triggers
- bacterial or viral triggers (ex. EBV)
- autoimmune (HLA and MHC gene mutations)
3
Q
patho
A
- 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
4
Q
TNF
A
- tumor necrosis factor
- cytokine that can cause cell death, cachexia (muscle wasting) and fever by stimulating IL-1 secretion
5
Q
Interleukin-1
A
a pro-inflammatory cytokine that increases WBC migration to the site, induces fever (endogenous pyrogen) and causes hyperalgesia (increased sensitivity to pain)
6
Q
pannus
A
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
7
Q
manifestations
A
- 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,