20. Rheumatoid arthritis

Question 1

What is RA?

Answer 1

• It’s a chronic inflammatory autoimmune disease involving the synovium of joints
• Inflammation of synovium can cause damage to cartilage and bone
• It is a systemic disease with may extra-articular manifestations
• Uncertain etiology, but genetic predispositions are necessary

Question 2

What is the epidemiology of RA?

Answer 2

Usual onset at 20-40 years-old

More common in women

Question 3

What are the clinical features of RA?

Answer 3

Joints:

• Inflammatory polyarthritis (joint swelling is the most common)
  
  • May involve every joint in the body except DIP (distal interphalangial) joints
  • Exclude RA if joint distribution is asymmetrical, OR DIP is involved, OR constitutional symptoms are absent (especially morning stiffness)
• Pain of joints motion
• Commonly affects joints of the hands (PIP, MCP), wrists, knees, elbows, anckles, hips and shoulders
  
  • Hand deformities:
    
    • Ulnar deviation of MCP joints
    • Boutonniere deformities of the PIP joints (PIP flexed, DIP hyperextended)
    • Swan-neck contractures of the fingers (MCP flexed, PIP hyperextended, DIP flexed)

Constitutional symptoms:

• Morning stiffness (present in all patients), improves as the day progresses
• Weight loss

Cutaneous:

• Thin skin, bruises easily
• Subcutaneous rheumatoid nodules

Pulmonary:

• Pleural effusion (very common) with low glucose fluid
• Pulmonary fibrosis
  
  • Honeycomb pattern on CXR and HRCT
  • Restrictive pattern on pulmonary function test
• Rheutmatoid nodules in the lungs
  
  • They can cavitate or become infected

Cardiac:

• Rheumatoid nodules in the heart (can cause conduction problems)
• Pericarditis

Eyes:

• Scleritis
• Scleromalacia (softening of sclera), if kept untreated ==> blindness
• Dry eyes

Hematological:

• Anemia of chronic disease

Felty’s syndrome:

• Triad of RA
• Neutropenia
• Splenomegaly

Other:

• Peripheral neuropathy
• Carpal tunnel syndrome
• Splenomegaly

Question 4

What are the steps of diagnosis of RA?

Answer 4

• Lab findings:
  
  • High titers of RF
    
    • Associated with more severe diseases and is non-specific
    • They rarely change with the diseases and thus are not useful for following the patient
  • Anti-CCP (anticitrullinated peptide antibodies)
    
    • Good specificity, but low sensitivity
  • Increased ESR and CRP
  • Normocytic normochromic anemia (anemia of chronic disease)
• Radiography:
  
  • ​Loss of juxta-articular bone mass (periarticular osteoporosis)
  • Narrowing of joint space
  • Bony erosions at the margins of the joint
• Synovial fluid analysis:
  
  • Non-specific

Question 5

What are the diagnostic criteria of RA?

Answer 5

Thoses with ≥ 1 joint with definite swelling, which is not better explained by another disease. Add total A-D score (scores ≥ 6/10 are diagnotic)

A. Joint involvement (swelling or tenderness +/- imaging evidence):

• 1 large joint = 0
• 2-10 large joints = 1
• 1-3 small joints = 2
• 4-10 small joints = 3
• > 10 joints (at least one small one) = 5

B. Serology:

• Negative RF and anti-CCP = 0
• Low positive RF or low positive anti-CCP = 2
• High positive RF or high positive anti-CCP = 3

C. Acute phase reactants:

• Normal CPR and ESR = 0
• Abnormal CRP or ESR = 1

D. Duration of symptoms:

• < 6 weeks = 0
• ≥ 6 weeks = 1

Question 6

What is the treatment of RA?

Answer 6

• Early, use DMARDs (disease-modifying antirheumatic drugs) as the 1st line of treatment
  
  • Best result when combining with methotrexate, sulfasalazine and hydroxychloroquine
• Immunosuppresion:
  
  • Steroids rapidly reduce symptoms and inflammation
    
    • IM methylprednisolone or oral prednisolone
    • Useful for treating exacerbation
    • Avoid long-term treatment to avoid side effects
  • Anti-TNF inhibiting agents (infliximab)
• Symptom relief:
  
  • _​_NSAIDs