Rheumatoid arthritis Flashcards
What part of a joint is affected in a degenerative joint disorder e.g. osteoarthritis?
Hyaline cartilage (degeneration, wearing with age)
What part of a joint is affected in an inflammatory joint disorder e.g. RA?
Synovium of the joint
What condition is characterised by a build up of crystal in the joints i.e. crystal arthropathy?
Gout
Which bacteria commonly causes septic arthritis?
Streptococcal
Name 3 viral infections that can cause inflammatory arthritis
Hep B
Hep C
Rubella (German measles)
Which cells in a joint capsule secrete synovial fluid?
Where can they be found?
Synovocytes
Synovium (serous membrane)
Give 2 purposes of synovial fluid
Metabolite exchange medium
Lubricant for synovial joints
Where are T cells made?
Cortex of the thymus gland
What virus causes glandular fever?
Epstein-Barr virus (EBV)
Which HLA gene is connected with RA?
HLA-DR4
Which autoimmune diseases are associated with HLA-DQ2?
T1DM
Coeliac disease
What are rheumatoid factors?
IgM autoantibodies directed against the Fc fragment of immunoglobulin G (IgG).
Which autoantibody are rheumatoid factors made from?
IgM
Which autoantibody to rheumatoid factors fight against?
IgG
Why is rheumatoid factor not good at diagnosing joint pain?
10-25% false positives in over 70s
If patient comes in with joint pain, RF will not diagnose RA.
What are some common clinical features in RA?
Young-middle aged females (20-50)
Pain and stiffness in joints
Gradual or sudden onset
Usually symmetrical, hands, feet, other joints
Often FH
Smoking increases the risk
When is stiffness most profound in RA?
In the mornings when they’re ‘trying to get going’
What are the 3 S’s for inflammatory arthritis?
Stiffness - early morning for more than 30 mins
Swelling - usually hand joints
Squeezing - painful to squeeze joint
Which joints are most commonly affected in RA?
Metacarpal/metatarsal-phalangeal joints of hands and feet
What features can be seen in the hand in RA?
List them in order of disease progression
Ulnar deviation of fingers + metacarpal-phalangeal subluxation
Swan neck deformities
Boutonniere deformities
Why can RA cause nerve compression?
C1/C2 atlantoaxial subluxation - involvement of these vertebrae can put pressure on the spinal cord
What is the classic positional presentation of pericarditis?
Sitting forward eases pain
Lying back decreases pain
Pericarditis can be a complication of RA and present as ACS with potentially no ECG changes
Which cytokine produced by the T-cell mediated immune response destroys articular cartilage and bone?
IL-1
In late disease, the synovium can get inflamed and proliferate. When this starts to invade surrounding tissues, what is the structure called?
Pannus
Very vascular structure, invades bones and cartilage
What blood results would you expect in RA?
Anaemia (normocytic normochromic), anaemia of chronic diseases
ESR/cRP: moderately raised
Immunology: Anti-CCP - +ve in 60% RA patients
ALP - raised
Albumin - decreased
If ALP is raised alongside bilirubin, GGT or ALT, what does this suggest?
That the raised ALP is coming from the liver, showing liver damage
If ALP is raised alongside calcium and phosphate, what does this suggest?
That the raised ALP is coming from the bone
What would an iron deficiency anaemia look like on a blood test?
Microcytic (low MCV)
What would a B12 deficiency aneamia look like on a blood test?
Macrocytic
Which 2 substances can effect the ESR?
Fibrinogen (levels increase in inflammation)
Immunoglobulins
What changes could be seen in an Xray of someone with RA?
Soft tissue swelling
Joint space narrowing
Erosions
Subluxation
Deformity
Juxta-articular osteopenia (reduced bone density next to the swelling)
What 2 drugs are given in combination treatment of RA?
Sulphasalazine
Methotrexate
What is the MoA of sulphasalazine?
What other drug is in this family?
Aminosalicylates
Anti-inflammatory, ?COX inhibition
Mesalazine
What is the MoA of methotrexate?
What other drug is in this family?
Inhibits the enzyme dihydrofolate reductas which inhibits DNA synthesis. This reduces lymphocyte proliferation
Azothiprine
What corticosteroid can be used short term to treat arthritis?
Prednisolone
Why are corticosteroids (prednisolone) useful in RA?
Think MoA
General immunosurpressors
Reduced transcription of cytokines e.g. IL-1 and IL-2
This reduces the proliferation of T helper cells (involved in autoimmunity)
How often is methotrexate given?
Once weekly
Name some side effects of methotrexate
Teratogenic (attacks any rapidly dividing cells)
Tiredness (signs of anaemia)
GI side effects - mouth ulcers, diarrhoea
Hair loss
Increased risk of infections
Name 2 monoclonal antibodies used in the treatment of RA
Infliximab
Rituximab
What is the MoA of infliximab?
Binds and blocks proinflammatory function of TNF-alpha
Anti-TNFa
What is the MoA of rituximab?
Anti-CD20 on B cells
How are infliximab and rituximab administered?
IV infusion
