Rheumatoid Arthritis

Question 1

Define rheumatoid arthritis.

Answer 1

Chronic inflammatory systemic disease characterised by symmetrical deformng polyarthitis and extra-articular manifestations.

Question 2

What is the aetiology of rheumatoid arthritis?

Answer 2

• Autoimmune disease of unknown cause.
• Associated with other autoimmune phenomenon (e.g. Raynaud’s phenomenon, Sjogren’s syndrome)
• and HLA DR-1 and DR-4 haplotypes.

Question 3

Whata is the pathophysiology of rheumatoid arthritis?

Answer 3

Inflammed synovium - increased angiogenesis, cellular hyperplasia, influx of inflammatory cells, changes in expression of cell surface adhesion molecules and cytokines.

Syniovium becomes hyperplastic and sublining infiltrated with T cells, B cells, macrophages and plasma cells.

Question 4

How common is rheumatoid arthritis?

Answer 4

• Common
• Prevalence is 1% of general population
• 3x more common in females
• Peaks in 30-50 year olds

Question 5

What is the typical presentation of rheumatoid arthritis?

Answer 5

• Gradual onset (occasionally rapid)
• Joint pain, swelling, morning stiffness, impaired function
• Usually affects peripheral joints symmetrically (occasionally monoarticular involvement e.g. knee)
• Fatigue, fever, weight loss
• Other: pleuritic chest pain (pleuritis/pericarditis), scleritis/uveitis

Question 6

What are the signs of rheumatoid arthritis on examination?

Answer 6

Arthritis affecting most sites in the hands

Early:

• Spindling of fingers
• Swelling of MCP and PIP joints
• Warm, tender joints
• Reduction in range of movement

Late:

• Symmetrical deforming arthropathy
• Ulnar deviation of fingers from subluxation (partial dislocation) at MCP
• Radial deviation of wrist
• Swan neck deformity (MCP and DIP fixed flexion, PIP extension)
• Boutonniere deformity (MCP and DIP extension, PIP flexion)
• Z deformity of the thumb
• Trigger finger (unable to straighten, tendon sheath nodule palpable), tendon rupture
• Wasting of small muscles of the hand, palmar erythema

Rheumatoid nodules - firm subcut nodules (e.g. on elbows, palms, over extensor tendons)

Signs of complications - involvement of several organs, vasculitis, lungs, heart, haematological (anaemia of chronic disease, megaloblastic, aplastic, heamolytic/Felty’s syndrome), neuromuscular, renal, eyes.

Question 7

Name 3 types of deformities that you can get in RA.

Answer 7

• Swan neck deformity (MCP and DIP fixed flexion, PIP extension)
• Boutonniere deformity (MCP and DIP extension, PIP flexion)
• Z deformity of the thumb

Question 8

What investigations should you do for rheumatoid arthritis?

Answer 8

Bloods:

• FBC - low Hb and high plt
• CRP/ESR - raised
• Rheumatoid factor (RF) - +ve in 60-70%, but also seen in Hep C, chronic infection and rheumatological conditions.
• Anti-cyclic citrullinated peptide (anti-CCP) antibody - +ve in 70%

Imaging:

• X ray of joints - erosions affecting subchondral bone first then causing joint space narrowing then.
• US - synovitis of the wrist and fingers

Other:

Disease activity score - ARC score which includes tender joint count, swollen joint count, functional sttays , pain, global assessment and CRP/ESR

Question 9

Why are these deformities in RA no longer common?

Answer 9

Most patients are treated with DMARDs at an early stage e.g. methotrexate