Rheumatoid Arthritis Flashcards
Rheumatoid arthritis?
Chronic, autoimmune joint disease affecting 1-2% of population; far more than just inflammation of the joints, it is systemic and affects connective tissue all throughout the body
Who is affected by rheumatoid arthritis?
80% of people with RA are women (suggesting that it is autoimmune)
Which joints does rheumatoid arthritis affect?
Non-weight bearing joints (small joints of fingers, toes, ankles)
What occurs to the joints that are affected?
deformed synovial joints -> more visible deformation than osteoarthritis
etiology?
- Autoimmune (HLA & MHC gene mutations)
- Bacterial or viral trigger (eg. Epstein barr virus)
- Complex trait etiology [environmental and genetic components]
patho?
- Combination of B cell and T cell autoimmunity. T helper cells are activated by interacting with antigen presenting cells when infected with the bacterial/viral trigger and release mediators/cytokines (eg. TNF, IL-1) that induce inflammation and communicate damage within the joint. T helper cells activate T cells -> targets synovial membrane -> inflammatory damage within the joint cavity. -> T helper cells activate B cells (now plasma cells) that produce a specific antibody that targets the joint, known as rheumatoid factor. Immune complex hypersensitivity (type 3); RF’s and IgG antibodies form immune complexes that deposit on the synovial membrane -> an attempt is made to remove them which results in inflammation. -> repeated autoimmunity and hypersensitivity -> ongoing inflammation -> complement activated d/t increased inflammation and WBC attraction. -> continuous damage, leading to obvious deformity in the joints -> T cells and Ab’s target the synovial membrane, cartilage and the underlying bone once cartilage is damaged. -> calcification -> joint fusion; difficult to mobilize the joint d/t extensive damage within it -> Pannus
What is significant to know about rheumatoid factor?
Not all pts will present with rheumatoid factor
What occurs during the calcification stage?
damaged bone will release calcium, which deposits within the joint.
What is the lesion that forms in RA?
Pannus
Pannus?
granulation tissue that develops within the joints
What occurs in RA when a Pannus forms?
- angiogenesis in synovium. The Pannus contains inflammatory cells, which release proteases (destructive enzymes) that further this tissue damage -> this is not beneficial in any way. proteases specifically target articular cartilage. -> Pannus is space-occupying within the small joints -> less room = decreased mobility
What occurs as the disease progresses?
the ligaments change their alignments -> alters how bones attach to bones (resulting in deformities)
Manifestations of RA?
- early age onset -> often manifestations begin when the women is in her 20s-30s
- non-specific manifestations occur new the beginning of the disease: fatigue, generalized pain, malaise (subtle onset)
- later on: fatigue intensifies, stiffness after inactivity overnight -> diff. to move fingers and toes
- as the disease progresses it begins to affect larger joints, as well as a variety of different areas within the body
What are some the extreme deformities that occur?
- Swan Neck Deformity (joint is misaligned, resulting in bent fingers/wrist representing a swan’s neck)
- ulnar shift/drift/deviation
- subcutaneous nodules
Dx of RA?
- hx, px
- xray (will not be revealing, could rule out a fracture)
- labs (CBC, CRP, ESR)- > exclude infection
- serology -> looking for antibodies
