Rheumatoid arthritis Flashcards
Genes which predispose an individual to RA are found in which region of the DNA?
HLA DR4
What is the definition of RA?
Rheumatoid arthritis is a multi-systemic, chronic, autoimmune inflammatory condition characterised by a symmetrical polyarthropathy which can result in significant loss of function.
What is the prevalence of RA?
~ 1%
What is the aetiology of RA?
The aetiology of RA is multifactorial with both genetic and environmental influences. HLA-DR4 is a genetic marker of prevalence and severity and it is known that there is an increased risk of RA development in smokers, who also tend to have more aggressive disease
Which WBC has a key role in the initiation of inflammation in RA?
T-lymphocytes appear to be the key effector cell. T-cells orchestrate the immune response through a host of cytokines.
How do macrophages contribute to the pathophysiological changes in RA?
Activated macrophages produce cytokines (intercellular messenger proteins) such as TNF-α and IL-1 which:
- stimulate inflammation
- attract other immune cells
- cause excess synovial fluid production
- cause cartilage destruction
- cause bone resorption
How do B-cells contribute to the pathophysiology of RA?
Activated B-cells in the synovium produce:
- rheumatoid factor &
- anticitrullinated protein antibodies
*NB, anti-CCP levels in the serum are used to detect these antibodies
What % of patients with RA test +ve for RF and anti CCP?
80%
High levels of RF and anti CCP are assoc. w/ ?
More severe disease and the presence of extra articular features
What % of patients with RA test +ve for RF and anti CCP?
80%
High levels of RF and anti CCP are assoc. w/ ?
More severe disease and the presence of extra articular features
Define synovitis
Inflammation and swelling of the synovial membrane
Macrophages and osteoclasts create chronically inflamed fibrous tissue known as?
Pannus
When is the peak age of onset for RA?
Fourth and fifth decades of life
How long do symptoms generally take to develop?
Weeks to months
What are the four main articular features of RA?
Joint pain, stiffness, swelling and loss of function
Which joints does RA usually target?
Small and medium joints (but can affect any) **in a symmetrical fashion
An atypical presentation of RA where there is an acute onset of symptoms affecting usually one (monarthritis) or multiple joints can occur. What is this known as?
Palindromic RA
What is the cause of “boggy swelling” in RA?
Synovitis
Today, RA should be identified prior to deformity and urgent referral for treatment should be within how many weeks of symptoms onset?
6 weeks
The wrists and which joints of the hand are usually affected in RA?
The MCP and PIP joints are usually affected. (There is sparing of the DIP joints).
Subluxation of the MCP joints occurs in RA. This causes the proximal phalanges to drift in which direction?
Ulnar and volar (palmar surface) direction
Name the two common deformities that occur in the digits of the hand
Boutonnières and swan-neck deformities
Describe boutonnière deformity
PIP flexion; DIP hyperextension.
