Rheumatoid arthritis (brief) Flashcards
How common is it?
1% prevalence. Incidence is low at 12,000 per year.
Who does it affect?
Incidence increases with age, with peak onset in the 4th and 5th decades. F:M 3:1
What causes it?
Synovitis with thickening of the synovial lining and infiltration by inflammatory cells. Generation of new synovial blood vessels induced by angiogenic cytokines, and activated endothelial cells produce adhesion molecules. The synovium proliferates and grows out over the surface of cartilage, producing a tumour like mass called a ‘pannus’. Pannus destroys the articular cartilage and subchondral bone, causing bony erosions.
What risk factors are there?
FHx. Genetics.
How does it present?
Typically, insidious onset of pain, early morning stiffness (lasting more than 30 minutes) and swelling of the small joints of the hands and feet.
There is spindling of the fingers caused by swelling of the PIPJs but not DIPJs.
The metacarpophalangeal and wrist joints are also swollen.
As the disease progresses, there is weakening of joint capsule, causing joint instability. Characteristic deformities of ulnar deviation, boutonniere deformity and swan neck deformity.
Joint effusions and wasting of muscles around the affected joints are early features.
Investigations
FBC
ESR and CRP raised in proportion to the activity of the disease.
Serum antibodies.
Anti-CCP has a high specificity and sensitivity for RA (90+80% respectively) and is useful to distinguish early RA from acute transient synovitis.
X-ray of the affected joints shows soft tissue swelling in early disease and later joint narrowing, erosions at the joint margins and porosis of periarticular bone and cysts.
Synovial fluid is sterile with high neutrophil count in uncomplicated disease.
Treatment
Goals are remission of symptoms, no cure. NSAIDS good for pain. Corticosteroids suppress disease activity but the dose required is often large. Disease-modifying anti-rheumatic drugs (DMARDS) such as methotrexate. Biological DMARDs, work by TNF alpha or something.
Conditions that would present similarly
Septic arthritis if in single joint. Symmetrical seronegative spondyloarthropathies. Psoriatic arthritis. Young woman with joint pains, also consider SLE. Acute viral polyarthritis must be considered in the early stages of presentation.
