RA Flashcards
What are the causes of RA?
- Genetics (non-modifiable)
- Smoking (modifiable)
- Infection
- infection may activate inflammation pathway that “prime” the development of RA
- Autoimmunity
- RF found in the blood
Why is mortality 30% higher in RA?
because of systemic effects
- heart
- eyes
- lungs
What does anti-CCP tell us about RA?
- It is an important marker for the diagnosis and prognosis of RA
- just as sensitive, but more specific that RF
- important in early detection, even prior to RA (family marker)
What does ANA stand for?
What is it used for?
- antinuclear antibody
- used as a general test to evaluate a patient for autoimmune disorders
- used to rule out other autoimmune disorders
What is ESR and CRP used for?
Which is better?
- detects the degree of inflammation in the body
- CRP has better indication of the actual amount of inflammation
What is the synovial membrane?
- thin layer of connective tissue (1-3 cell layers thick)
- found between the joint capsule and synovial cavity
What is synovial fluid?
What is it composed of?
- ultrafiltrate of blood that crosses the synovial membrane into the joint cavity
Composed of:
Hyaluronan - regulates cartilage viscosity
Lubrican - lubricates surface of cartilage
What is fibronectin?
- it is the glue that holds the collagen cells together in the cartilage
What cells produced synovial fluid (hyaluronan and lubrican)?
synoviocytes
What is pannus formation?
- growth of fibrous tissue in the joint
- causes loss of bone and erodes cartilage
What is present in the synovial fluid in RA patients?
- activated inflammatory immune system activated cells
What are inflammatory immune system activated cells?
fibroblast-like synoviocytes
macrophage-like synoviocyes
macrophages
B and T cells
- all mediators of inflammation
What are osteoclasts?
- cells that promote the breakdown of bone
- stimulated by immune response
Fibroblasts are stimulated by the immune system.
What do they cause?
- pannus formation (leading to loss of cartilage and bone)
- matrix metalloproteinases (degradation of bone matrix)
- pro-inflammatory cytokines
What does the activation of T cells cause in RA?
- productions of PGs, cytokines and cytotoxins
- release of cytokines, matrix metalloproteinases (bone degradation), osteoclasts and B cells (Abs –> cartilage phagocytosis)
What is IL-6?
How does it contribute to RA?
- IL-6 is the most abundant cytokine in the synovium of RA pts
Causes:
- stimulation of liver reactants, osteoclast, B cells, T cells
- correlated with increased disease activity
- anemia of chronic disease
What are the 3 ways B cells affect RA?
- Activated ABs
- RF
- anti-CCP
- ANA - Stimulate cytotoxin and free radical release
- damages synovium and bone
- phagocytosis of cartilage and bone –> more inflammation - Activates T cells
- positive feedback loop between humoral and cellular immune responses
- releases pro-inflammatory cytokines (IL-1, IL-6, TNF alpha)
Describe the clinical symptoms of RA?
- symptoms progress over months
- pain/stiffness usually presents in 1-2 joints (eventually moves to 5+)
- symmetrical, hot swollen joints
- subcutaneous nodules
- pain >1 hour after waking (lasts all day)
- systemic complaints (fatigue, weakness, low fever, low appetite, depression)
Which joints are the most affected in RA?
- hands (PIPs and DIPs)
- wrists (MCP)
- shoulders
- neck
- feet
If you did a blood platelet test in a RA pt, what would you find?
- thrombocytosis (too many platelets)
- risk of blood clots/CV event
What could a joint radiograph show in a RA pt?
- peri-articular osteoporosis
- joint space narrowing
- erosions
What are the 5 extra-articular effects of RA?
- rheumatoid nodules
- cardiopulmonary disease
- pericarditis
- atherosclerosis…from chronic inflammation
- eye diseases
- episcleritis
- sjogren’s syndrome
- dry eyes and mouth
- rheumatoid vasculitis
- digital finger infarction (black finger)
75-80% of pts with RA have a _____________ disease course
cyclic-type
why are steroids dangerous for RA patients?
- they deplete bone of their calcium
- make patient’s bone weak and brittle
