Rheumatoid Arthritis Flashcards
Definition
Seropositive (+ve for auto-antibodies) inflammatory arthropathy
Inflammatory or non-inflammatory
Inflammatory
Epidemiology
M/F, age
Commonly affects females
Affects any age group (peak age: 35-50)
Risk factors for development of RA
Cigarette smoking
Infections
Stress
Genetics
Auto-immune condition
HLA-DR4 mediated
Which type of hypersensitivity reaction is it?
Type IV
Commonly affected areas
Peripheral joints Hands: PIP, MCP, wrists (*NOT DIP joints*) Elbows Shoulders TMJ C1 and C2 vertebrae Hips Knees Ankles Feet
Symmetrical or asymmetrical distribution?
Symmetrical
Pathogenesis
Synovium is the main structure involved.
Immune response is initiated against synovium
Inflammatory pannus is formed - inflammed synovium which encourages inflammatory cells to the area.
Inflammatory cells attack the area leading to joint cartilage destruction.
Osteoclasts eat up the bone
Immune response
Antigen -> dendritic cell (APC) -> T cell activation
- T cell activation -> B cells (which then make auto-antibodies e.g. rheumatoid factor)
- T cell activation -> macrophages (which release substances e.g. TNF-alpha, IL-1, IL-6 which contribute to the inflammatory response
Clinical features
Inflammatory features - joint swelling, heat, pain, erythema Morning stiffness over 30 mins Symptoms improve with movement Flare ups common
Examination
Squeeze test
Palpate individual joints
Investigations
Auto-antibodies - rheumatoid factor - anti-CCP Bloods - raised inflammatory markers (CRP, PV, ESR) X-rays - normal in initial stages - eventually show erosions, soft tissue swelling, osteopenia (bone thinning) Ultrasound - detects synovitis MRI - detects abnormalities quickest
Auto-antibodies: Rheumatoid factor
IgM produced by B cells
Not sensitive or specific
- many patients have RA without having the rheumatoid factor auto-antibody
Auto-antibodies: Anti-CCP
Preferred auto-antibody test
Very specific - not +ve in any other conditions
Some patients can have RA without a +ve Anti-CCP
