What labs and treatment plan should be ordered for a patient with suspected Rheumatoid Arthritis (RA) presenting with hand and shoulder pain, and difficulty sleeping due to pain?

Diagnostic and Treatment Plan for Suspected Rheumatoid Arthritis

Laboratory Tests for Diagnosis

For a patient with suspected rheumatoid arthritis presenting with hand and shoulder pain, the essential laboratory workup should include rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and complete blood count with differential, along with renal and hepatic function tests. 1

Additional laboratory tests to consider:

• Urinalysis for proteinuria (to monitor for amyloidosis)
• Hepatitis B and C testing (if considering biologic therapy)
• Tuberculosis testing (if considering biologic therapy)

Imaging Studies

Imaging studies should include:

• Plain radiographs of hands and feet (posteroanterior view) as the initial imaging modality 2
• Ultrasound of affected joints to detect synovitis and erosions that may not be visible on radiographs 2
• MRI may be considered if radiographs don't show damage but clinical suspicion remains high 2

Ultrasound and MRI are superior to clinical examination in detecting joint inflammation and can predict progression from undifferentiated inflammatory arthritis to clinical RA 2.

Treatment Plan

First-Line Therapy

• Methotrexate is the preferred first-line DMARD, starting at 7.5-15mg weekly and escalating to 20-25mg weekly as needed 1
• Subcutaneous administration is preferred over oral due to better bioavailability 1
• Folic acid supplementation (1mg daily) to reduce side effects

Alternative DMARDs (if methotrexate is contraindicated)

• Leflunomide
• Sulfasalazine

Adjunctive Therapy for Symptom Relief

• NSAIDs for pain and inflammation
• Short-term oral glucocorticoids (<3 months) as bridge therapy while DMARDs take effect 1
• Local glucocorticoid injections for particularly painful joints

Second-Line Therapy (if inadequate response to methotrexate)

• Add biologic agents (TNF inhibitors, abatacept, or tocilizumab) 1
• Consider JAK inhibitors with attention to safety concerns 1

Monitoring Plan

• Monitor inflammatory markers (ESR, CRP) every 4-6 weeks after treatment initiation 1
• Assess disease activity every 1-3 months using validated measures like DAS28, SDAI, or CDAI 1
• Evaluate structural damage with radiographs every 6-12 months during first years 1
• Regular joint examinations to assess for improvement or progression

Important Considerations

• Early diagnosis and treatment are crucial for better outcomes 3, 4
• The treatment target should be remission or low disease activity within 6 months 1
• Consider comorbidities when selecting medications 1
• Assess for extra-articular manifestations that may require additional treatment 1
• Patient education about the chronic nature of RA and importance of medication adherence

Differential Diagnosis

Be aware of conditions that may mimic RA:

• Psoriatic arthritis (may target DIP joints or affect just one ray)
• Osteoarthritis (especially erosive OA affecting IP joints)
• Gout (may superimpose on pre-existing hand OA)
• Hemochromatosis (mainly targeting MCPJs, wrists) 2

Ultrasound can help differentiate between inflammatory and non-inflammatory arthritis, though it may not always distinguish between different types of inflammatory arthritis 2.