Inflammatory Arthritis Flashcards
(102 cards)
What is rheumatoid arthritis?
Chronic inflammatory autoimmune disorder characterized by joint pain, swelling, and synovial destruction
What are the causes of rheumatoid arthritis?
Idiopathic autoimmune disorder, however believed to be multifactorial:
- Genetic predisposition - seems to be associated with specific HLA types e.g. HLA DRB1 gene
- Environmental triggers - infection and smoking increase anti-CCP
- Hormonal factors - higher incidence in females (3:1)
Who is rheumatoid arthritis most common in?
Peaks 35-50 year old women
Describe pathophysiology of rheumatoid arthritis
- Non-specific inflammation affects the synovial tissue, which is then amplified by activation of T cells
- Leads to inflammatory joint effusion + synovial hypertrophy + progressive destruction and deterioration of cartilage and bone
- Inflammatory pannus (granulation tissue) forms which produces proteinases that destroy the cartilage extracellular matrix
- Tendon rupture and soft tissue damage can occur leading to joint instability and subluxation
- In the chronic phase this includes fibrosis + deformity
Describe the generation of auto-antibodies and activation of the immune response in rheumatoid arthritis
- Specific genes lead to the conversion of arginine (A) into citrulline (C) → protein will unfold due to loss of positive charge
- The unfolded protein acts as an antigen causing an autoimmune response mediated by auto CD4+ T cells
- Driven by a type IV hypersensitivity mechanism, but secondary type III hypersensitivity responses also occur
- Anti-citrullinated peptide antibodies (can be generated in the lungs from smoking) can form immune complexes with the citrullinated proteins produced in an inflamed synovium leading to neutrophil infiltration and activation
What is the rheumatoid factor? Who has it?
- An auto-antibody (IgM or IgA) that binds to Fc region of IgG
- Found in ~80% of patients with RA
What is a high titre of RF an indication of?
Risk of extra-articular disease
When is anti-CCP present in body? What is it associated with?
Can be present for several years prior to articular symptoms
-Associated with erosive damage and current/previous smoking history
What do anti-CCP levels indicate?
- Correlates with disease activity and levels remain positive despite treatment
- Has low sensitivity so absence does not exclude disease
What are some articular manifestations of rheumatoid arthritis?
- Polyarthralgia
- SYMMETRICAL pain and swelling of affected joints
- Rapid onset
- Most commonly in the small joints of the hands and feet (PIPs/MCPs and MTPs)
- Larger joints e.g. knees, shoulders, elbows and atlantoaxial joint can also be affected as the disease progresses
- Early morning stiffness for MORE THAN 30 mins that usually improves with activity
- Reduction in grip strength
- Joint deformities (‘rheumatoid hand’)
- Swan neck deformity: PIP hyperextension and DIP flexion
- Boutonniere deformity: PIP flexion and DIP hyperextension
- Atlanto-axial subluxation
What are some clinical signs of r. arthritis?
- Symmetrical swelling of affected joints
- Positive compression tests of MCP and MTP joints
- Bouchard’s nodes - bony swellings of proximal IPJ (also see in OA)
- 25% of patients develop rheumatoid nodules, most commonly on extensor surfaces or sites of frequent mechanical irritation
- Necrotising granulomas with a palisade of macrophages surrounding a central area of collagen necrosis
- Synovial herniation - cysts e.g. Baker’s cyst
What are some extra-articular manifestations of rheumatoid arthritis? Lungs, heart, skin, eye, other MSK?
- Constitutional symptoms: low-grade fever, myalgia, malaise, fatigue, weight loss, night sweats
- Lungs: interstitial fibrosis, pneuomconiosis (Caplan syndrome), rheumatoid lung nodules, pleuritis, pleural effusions
- Heart: pericarditis, myocarditis, increased risk of CVD
- Skin: pyoderma gangrenosum, Raynaud’s phenomenon, rheumatoid skin nodules
- Eye: keratoconjunctivitis
- Other MSK: osteopenia/osteoporosis, Sjogren syndrome
What blood tests can you do for rheumatoid arthritis?
- Raised inflammatory markers (CRP, plasma viscosity, ESR)
- Autoantibodies: presence of Rheumatoid factor (60-70% specific) or anti-CCP antibodies (90-99% specific)
What will an X-Ray show in early r. arthritis? Late arthritis?
- Early disease: can be normal, may show soft tissue swelling and periarticular oseopenia
- Late disease: erosions, sublaxation
What can an USS show in r. arthritis?
Useful in detecting synovial inflammation if there is clinical uncertainty; good for treatment changes
When should you use MRI in rheumatoid arthritis?
Extremely sensitive but only use if diagnostic doubt
What can be used for symptomatic relief in r. arthritis?
Analgesics, NSAIDs and steroids
What do rheumatoid nodules not always respond to and what should you do?
DMARDs - excision if problematic but recurrence is high
What is the first line medication for r. arthritis? Examples
cDMARDs (conventional disease modifying anti-rheumatic drugs)
-E.g. oral methotrexate (first choice), subcutaneous methotrexate, leflunomide, or sulfasalazine
When should you aim to start patient on cDMARDs for r. arthritis?
Within 3 months of symptom onset
When should you administer bDMARDs?
Given if have tried 2 DMARDs and patient still has DAS28 score > 5.1
What is second line treatment for r. arthritis? Examples
bDMARDs (biological DMARDs)
- eg. anti-TNF agents and T cell receptor blockers
What other treatments can be used for r. arthritis?
-Physiotherapists, occupational therapists, podiatrists and orthotists
- Surgery for resistant disease, to control pain, or to improve/maintain function (synovectomy, joint replacement, joint excision, tendon transfers, arthrodesis and cervical spine stabilisation)
What can occur in long standing disease involvement of the cervical spine in r. arthritis?
Atlanto-axial subluxation → cervical cord compression