Rheumatoid Arthritis Flashcards
- Approx. 1% of adults
- Women:Men -> 5:2
- Onset: 35-50 years
- Ethnicity: higher prevalence in Aboriginal population & lower prevalence in Asian population
Prevalence of RA
RA is an autoimmune disease (also known as an immune mediated inflammatory disease)
In response to immunological factors, synovial membranes become inflammed
Genetic susceptibility + environmental triggers (likely multifactorial)
RA Pathophysiology
Inflammation of synovial membrane
Hyperplasia (synovial cell proliferation)
↑ vascularity (↑ blood flow)
Infiltration of inflammatory cells resulting in production of enzymes that causes inflammation (e.g. cytokines & tumor necrosis factor)
Articular damage caused by PANNUS (granulation tissue formed within synovium)
Synovitis
In response to immunological factors, the synovium becomes swollen and cells begin to proliferate -> hyperplasia
A densely cellular membrane (pannus) spreads over articular cartilage and erodes the underlying cartilage and bone
Pannus may extend over time to the opposite articular surfaces creating fibrous scar tissue, adhesions, & ankylosis
Bone becomes osteopenic, ligaments and tendons are damaged/ruptured, and surrounding musculature deteriorate leaving the joints unstable/prone to deformity
RA effected joint
- Genetics
- Rheumatoid Factor (RF) HLA-DR4
- Pregnancy and hormones
- Environmental factors
Risk Factors of RA
Familial history of RA - overall increased risk by 2x
Prevalence in monozygotic (identical) twins: 15-35%
Prevalence in dizygotic (fraternal) twins: 5%
RA Genetic Factors
A genetic marker; present in 80% of people with RA
Accounts for ~30% of the genetic risk for RA
Titers: 1:20 (normal); 1:.20 to 1:80 (grey zone); 1:160 (typical positive result)
High RF can be present in people with Lupus, Syphilis, Chronic Hepatitis, or Idiopathic Pulmonary Fibrosis
Elevated RF in 5-10% of healthy persons >60 years old
Seronegative Arthritis: RF negative & with clinical symptoms of RA; found in 30% of patients
Rheumatoid Factor
↑ risk of RA onset after child birth
- Breast feeding (associated w/ ↑ prolactin)
Oral contraceptive use appears to associate with reduced risk, likely by postponing disease onset
Postmenopausal hormone use
- inconsistent findings
Pregnancy and Hormonal Factors
Cigarette smoking (STRONG risk factor)
- ↑ risk of RA esp. in men
- Associated w/ seropositive RA (RF +)
Occupation
- Miners: Silica exposure
- Farmers: Pesticide exposure
Diet; Reduced risk with:
- Olive oil consumption
- Fish consumption (>3x/week)
- Drinking tea (>3cups/day) - antioxidants
Environmental Factors
1) Morning Stiffness > 1 hour (≥ 6weeks)
2) Arthritis of ≥ 3 joints (≥ 6weeks)
3) Arthritis of hand joints (≥ 6weeks)
4) Symmetric arthritis (≥ 6weeks)
5) Rheumatoid nodules
6) Serum rheumatoid factor postive
7) Radiographic changes
* A diagnosis made when ≥ 4/7 criteria are met*
Criteria for RA
- Pain
- Fatigue
- Stiffness
- ↓ ROM
- Often involves small joints (MCP, PIPI, MPT, IP joints)
- Often symmetrical
- Swelling
- Joint deformity; instability of the joint
- Muscle Atrophy, general deconditioning
- Extra-articular features
Clinical Features of RA
Nodules developed under the skin (subcutaneously)
Typically found in the elbow, finger, wrist, and hip joints, lower back & Achilles tendon
Occasionally in heart & lung tissue
Found in 7% at the time of initial diagnosis
Affects ~30% of patients at some point during the disease
Rheumatoid Nodules
- Cold fingers/toes
- Color changes in skin in response to cold/stress
- Numb, prickly feeling or stinging pain upon warming/stress relief
Raynaud’s Phenomenon
Prevalence: 17% of RA patients
What happens:
- Vasopasm in capillaries when exposed to cold/stress
- Capillaries narrowing & temporarily limiting blood supply
- Affects fingers, toes, ears, nose, lips
Management: keep warm
Severe cases (very rare): medications (vasodilator), sympathetic nerve surgery
Secondary Raynaud’s Phenomenon
1) Medications
2) Rehabilitation Interventions
3) Lifestyle Modifications/Self-Care
4) Surgery
RA Management
