23 - Rheumatoid Arthritis Flashcards
Describe the burden of RA
- Associated w/ reduced QOL, disability, decreased life expectancy, and increased risk of CV disease and mortality
- Can be associated w/ systemic manifestations (many other organs in the body)
Definition of RA
- Chronic, systemic autoimmune inflammatory disease characterized by symmetric and erosive polyarthritis causing pain, stiffness, and fatigue
- If not treated appropriately, can result in joint destruction and severe disability that can disrupt multiple aspects of a px life
- Lifelong condition but can be in remission w/ appropriate pharm therapy
Pathophysiology of RA
- Most px w/ RA form antibodies called rheumatoid factors and anticitrullinated protein antibody (ACPA)
- Involves a complex interaction of many extracellular and intracellular molecules (inflammatory factors)
- Inflammatory mediators including tumour necrosis factor-alpha, IL inhibitors (IL-1, IL-6), T-cell, memory beta cells
Risk factors for RA
- Genetic predisposition
- Exposure to unknown environmental factors
- Age, gender, obesity, smoking
Difference in clinical presentation of OA vs. RA
- Onset -> RA = earlier (25-50 y/o); OA = later (usually > 40 y/o)
- Development -> RA = more rapidly; OA = slow
- Symmetrical -> RA = symmetrical; OA = usually non-symmetrical onset
- Pain -> RA = pain decreases w/ activity and increases w/ inactivity; OA = pain worsened by activity
- Tenderness -> RA = common; OA = uncommon
Difference in joints affected for OA vs. RA
- OA = knees, hip, hands
- RA = classically arthritis of the hand (especially PIP, MCP, and wrist joints)
Difference in morning stiffness for OA vs. RA
- OA = generally < 1 h
- RA = > 1 h
Difference in presence of systemic sx of OA vs. RA
- OA = none
- RA = common
Difference in lab values of OA vs. RA
- OA = normal
- RA = ESR/CRP; RF/ anti-CCP
Difference in radiographs of OA vs. RA
- OA = joint space narrowing, osteophytes
- RA = joint space narrowing, erosions
Sx of RA
- Joint pain and stiffness > 6 weeks, stiffness lasts > 1 h
- May experience fatigue, weakness, low-grade fever, loss of appetite
- Muscle pain and afternoon fatigue may be present
- Joint deformity is generally seen late in the disease
Signs of RA
- Joint involvement is frequently symmetrical
- Tenderness and warmth and swelling over affected joints (usually hands and feet)
- Systemic sx may be present
- Rheumatoid nodules may be present
What are the 2 groups of RA px?
- Early RA (ERA) = px w/ sx of less than 3 months duration
2. Established disease = px have sx due to inflammation and/or joint damage
Clinical course and prognosis of RA
- 80% have cyclic-type of progressive disease course
- Time to diagnosis and initiation of DMARD therapy is crucial
- Early diagnosis = w/in 6 months of the onset of joint sx
- Joint damage begins w/in 2 years of sx
How is RA diagnosed?
ACR/EULAR 2010 criteria requires 6 or more points
Role of lab values in the diagnosis of RA
- Labs normal > 30% of the time
- RF or anti-CCP positive px = worse prognosis
- RF detectable in 60-70% of px
- Anti-CCP detectable in 50-85% (can be detected years before diagnosis)
- Acute phase reactants may also be elevated -> not specific to rheumatic disease (C-reactive protein, erythrocyte sedimentation rate)
Other diagnostic tests for RA
- Joint fluid aspiration may show increased WBC counts w/o infection, crystals
- Joint radiographs may show periarticular osteoporosis, joint space narrowing, or erosions
DAS28 assessment tool for RA
- Number of swollen joints at 28 sites
- Number of tender joints at 28 sites
- Pt estimate of global status
- ESR or CRP value
- Score > 5.1 = high disease activity
- Score 3.2 – 5.1 = moderate disease activity
- Score 2.6 to < 3.2 = low disease activity
- Score < 2.6 = remission