Rheumatoid Arthritis

Lab Workup

• Rheumatoid factor (RF): moderate sensitivity (negative in about 20% of patients) and limited specificity (can be positive in hepatitis, bacterial endocarditis, etc.)
• Citrullinated cyclic peptide (CCP): very specific, predictive
• C-reactive protein and ESR both very sensitive for inflammation but non-specific for RA
• Anemia of chronic disease

Synovial Fluid

• 2k-50k/mL neutrophilic

Imaging

• Hand and feet x-rays (view image)
• 3-views: marginal erosions (view image), late RA-subluxation

Other Rheumatic Disease

• Lupus
• Seronegative spondyloarthritis
  • Especially psoriatic arthritis
• Crystal arthritis:
  • Gout
  • Pseudogout

Viral Arthritis

• Parvovirus B19
• Hepatitis B, C

Sarcoidosis

Endocrinopathy

• Thyroid disease
• Hemochromatosis (MCP 2/3)

Short-Term Therapy

Quick onset, unsafe in high doses long term

• NSAIDs: symptom relief only; NSAIDS do not slow/modify disease
  • Celebrex, diclofenac, naproxen
  • Usually oral; dosing depends on agent
• Glucocorticoids: have some potential to slow/modify disease (weak DMARDs)
  • Hydrocortisone, PO or IV
  • Methylprednisolone, PO, SQ or IV
  • Prednisone, PO only

Long-Term Therapy

DMARD = disease-modifying anti-rheumatic drugs (DMARDs)

Conventional Disease Modifying Anti-Rheumatic Drugs (cDMARDs)

• Hydroxychloroquine: QD or BID PO
  • Generally well tolerated
  • To reduce risk of retinal toxicity, limit to ≤5 mg/kg daily
  • QTc prolongation may occur
• Leflunomide: QD PO
  • Teratogenic
• Methotrexate: Weekly PO or SQ with folic acid
  • Teratogenic
  • CMP monitoring
• Sulfasalazine: BID PO
  • Check G6PD prior
• Azathioprine: BID PO
  • Check TPMT prior

Biologic Disease Modifying Anti-Rheumatic Drugs (bDMARDs)

Large molecules so have to be injections: subcutaneous (SQ) or intravenous (IV) administration

• TNF-alpha inhibitors
  • Adalimumab, SQ
  • Certolizumab pegol, SQ
  • Etanercept, SQ
  • Golimumab, SQ or IV
  • Infliximab, IV
• B-cell targeting medications
  • Rituximab, IV
• IL6 axis inhibitors
  • Sarilumab, SQ
  • Tocilizumab, SQ or IV
• CTLA4 agonist
  • Abatacept, SQ or IV

Targeted Synthetic Disease Modifying Anti-Rheumatic Drugs (tsDMARDs)

• JAK inhibitors
  • Baricitinib
  • Tofacitinib
  • Upacitinib

Occupational therapy/physical therapy are vital.

• Goal of early inflammation suppression
  • Prevent joint damage (damage is irreversible)
  • Lower CV risk
• Complications
  • Inflammatory lung disease (view image)
  • Vasculitis
  • AA amyloid

Disease Overview & Clinical Presentation

• Low grade fever can occur
• 5th MTP most common joint affected with RA (view image)
• C1/C2 subluxation is a complication
• Spares DIPs, thoracic and lumbar spine

Diagnostic Workup & Differential Diagnosis

• Rheumatoid factor (RF) sensitive: If low-positive and low suspicion of RA, check hepatitis serologies
• Citrullinated cyclic peptide (CCP): Specific and predictive
• Early x-rays: Marginal erosions, osteopenia
  Late x-rays: Subluxuation, osteoporosis

Treatment

• Glucocorticoids: Weak DMARDs if NSAIDs didn’t modify disease -> NSAIDs are not DMARDs
  • Glucocorticoids are effective symptom relievers and weak DMARDs, and may serve as a good bridging agent if NSAIDs are not adequate until more potent DMARDs can take effect. However, glucocorticoids have many long-term adverse effects, and the goal should be to use them at as low a dose and for as short a time as possible.
• Methotrexate is gold standard, first line