Rheumatoid arthritis Flashcards
What is rheumatoid arthritis (RA)?
- RA = autoimmune, inflammatory condition characterised by symmetrical swelling in multiple joints (typically affects the hands)
What are some risk factors which predispose to rheumatoid arthritis?
- female
- HLA (human leucocyte antigen): HLA-DRB1 gene
What are the immunological abnormalities of rheumatoid arthritis (RA)?
- the normal immunological mechanisms that help fight infections and destroy malignant cells target normal tissue, resulting in joint damage
- T-lymphocytes play a key role in initiating inflammation in RA, with B-cells and activated macrophages also playing important roles
- the activated cells produce cytokines (intracellular messenger molecules)
What are some actions of cytokines (eg. TNF-α, IL-1)?
- stimulation of inflammation
- attraction of other immune cells (chemotaxis)
- excess synovial fluid production
- cartilage destruction
- bone resorption
- stimulation of B-lymphocyte differentiation and maturation
- increased antibody production, including production of rheumatoid factor
What are the antibodies produced by activated B-cells in the synovium which occurs in RA?
- rheumatoid factor (Rf) and anti-citrullinated protein antibodies (anti-CCP)
- they are found in about 80% of patients with RA
- note: high lvls of antibodies are associated with more aggressive disease and the presence of extra-articular features
What is the pathology of rheumatoid arthritis (RA)?
- the main pathological abnormality in RA is synovitis
- as inflammatory cells infiltrate the synovium, it proliferates
- macrophages and osteoclasts create a layer of chronically inflamed tissue (pannus), which extends from the joint margins and erodes the articular cartilage
- extensive erosions of cartilage and bone lead to joint deformity
- ligament insertions (entheses) are a common site of inflammation and the thickened joint capsule swells
Rheumatoid arthritis joint vs normal joint…
What are the clinical features of rheumatoid arthritis (RA)?
- inflammatory joint pain/stiffness/swelling/erythema (eases with movement/throughout day)
- note: early morning stiffness (lasting more than 30 mins)
- typically affects joints symmetrically (hands)
- synovitis in wrists (MCPs and PIPs)
- joint deformities: mallet, Boutonniere, swan-neck, ulnar deviation
Ulnar deviation of hands…
- ulnar deviation results from MCP joint inflammation/subluxation
Mallet finger, Boutonniere, and swan-neck deformities…
- Mallet: flexion of DIP joint
- Boutonniere: PIP flexion and DIP hyperextension
- Swan-neck: MCP flexion, PIP hyperextension, DIP flexion
- (all due to laxity or contraction of flexor/extensor tendons due to synovitis)
Ulnar styloid…
- subluxation of the wrist joint produces a prominent ulnar styloid
What are the extra-articular features of rheumatoid arthritis (RA)?
- Rheumatoid nodules: common on fingers, elbows, achilles
- Tenosynovitis and bursitis: commonly affects flexor tendons and olecranon/subacromial bursae
- Carpal tunnel syndrome: synovitis can cause peripheral nerve pathology
What are the extra-articular features of rheumatoid arthritis (RA)?
- Rheumatoid nodules: commonly affects fingers, elbows, and Achilles tendon
- Tenosynovitis and bursitis: commonly affects flexor tendons of fingers, and olecranon and subacromial bursae
- Carpal tunnel syndrome: synovitis can cause peripheral nerve pathology
What are the systemic features of rheumatoid arthritis (RA)?
- RA can make patients feel systemically unwell (fever, weight loss, fatigue)
How can RA affect distant organs?
- Anaemia: can be anemia of chronic disease, NSAIDs can cause iron deficiency anaemia, DMARDs can cause anaemia through bone marrow suppression
- Felty syndrome: RA, splenomegaly, neutropenia
- Rheumatoid lung disease: pneumonitis can cause fibrosis and scarring of the lungs leading to pulmonary fibrosis
