PHR 937 Block 1 kaitlyn

common joints affected by RA

hands, feet

also: shoulders, elbows, hips, knees

- symmetrical

proximal interphalangeal (PIP)

metacarpophalangeal (MCP)

metatarsalphalangeal (MTP)

common joints affected by OA

hands, weight bearing joints

also: neck, back

what tissue does RA target?

synovial

synovium

tissue that lines joints, tendons, and bursae

- contains macrophages and fibroblasts

- target of RA

lymph nodes

filter lymph - site of immune activation

rheumatology

focused on diseases of the joints and the surrounding soft tissue and connective tissue

rheumatoid arthritis (RA)

a chronic inflammatory disease characterized by joint swelling, joint tenderness, and destruction of synovial joints - leading to severe disability and premature mortality

RA overview

- a chronic autoimmune disorder

- symmetrical erosive synovitis

- chronic fluctuating disease

- may result in joint destruction and disability

RA etiology

overall, unknown cause

- infectious: mycoplasma, epstein-barr, rubella

- genetic predisposition: major histocompatability complex and antigen presenting cells

- autoimmune: trouble differentiating between self and non-self

RA pathophysiology

1. arthriogenic antigen exposed to a genetically susceptible host

2. antigen activates T and B cells

3. chronic inflammation of synovial tissue (lines the joints) - called a pannus

4. pannus invades cartilage

5. bone and cartilage erosion

pro-inflammatory cytokines

TNF-α

IL-1

IL-6

how do cytokines affect the joints in RA?

- they produce metalloproteinases/ other cytotoxic substances leading to the erosion of bone and cartilage

- they also attract other inflammatory mediators to the joint, perpetuating the destructive process

- ultimately are responsible foe the destruction of the joint

RA presentation

small joints affected 1st

joint swelling

rheumatoid nodules

fatigue (usually later in the day)

weakness

low grade fever

musculoskeletal pain

joint stiffness (usually 30+ mins in the morning)

RA lab results

- antinuclear antibody (ANA) + (autoimmune disease marker)

- rheumatoid factor (RF) +

- anti-CCP +

- ↑ ESR and ↑ CRP (inflammatory markers, non-specific)

- joint fluid aspiration + for neurtophils, high protein content (non-specific inflammatory arthritis)

- mild to moderate normocytic anemia

RA imaging

radiologic tests show:

- joint space narrowing

- soft tissue swelling

- bony erosions

extra-articular involvement

- rheumatoid nodules

- vasculitis

- pulmonary fibrosis

- cardiovascular involvement

- Fetty's syndrome

joint deformities

structural changes in joints due to RA

- swan neck

- boutonniere

- hammer toe

- hyperextension