Rheumatoid Arthritis Flashcards
how is rheumatoid arthritis defined?
symmetrical inflammatory arthritis affecting mainly the peripheral joints
What is the ratio of females to males with rheumatoid arthritis?
3:1
What percentage of the UK population currently have RA?
1%
What genetic factor is thought to mediate RA?
HLA-DR4
What are the potential triggers that could cause RA?
infections
stress
cigarette smoking
What joints does RA affect?
Hand joints wrists elbows shoulders TMJs C1/C2 hips knees ankles feet
What time frame would be described as early RA?
less than 2 years since symptom onset
What two structures in the joint are affected by RA?
Synovium and tenosynovium
What are the clinical features of RA?
Prolonged morning stiffness.
Involvement of small joints of hands and feet.
Symmetric distribution.
Positive compression tests of metacarpophalangeal(MCP) and metatarsophalangeal(MTP)joints.
What autoantibodies are associated with RA?
Rheumatoid factor(Rheumatoid IgM)
Antibodies to cyclic citrullinated peptide
Anti-CCP antibodies
Describe the pathogenesis of RA
- Spongy mass of inflammatory cells in synovium
- Attracts blood cells and cytokines
- End result is inflamed synovium which activates osteoclasts
- Osteoclasts dissolve bone, causing erosion and joint damage
What imaging is used in the diagnosis of RA?
Plain x-rays of hands and feet.
Ultrasound scanning.
MRI scans.
What can be seen on an X-Ray with RA?
Soft tissue swelling .
Periarticular osteopenia.
Erosions.
What is the disadvantage of X-Rays in RA?
Absence of findings in early disease
Why are ultrasound scans potentially more useful than X-Rays
Can detect upto 7 times more MCP erosions than plain x-ray in early RA.
Useful in making treatment changes
Why are MRIs potentially more useful than an X-Ray in RA?
Integrity of tendons can be assessed
distinguish synovitis from effusions
detect erosions earlier
monitors disease activity
What scoring system is used to asses disease activity in RA?
Disease Activity Score 28(DAS 28)
**due to 28 joints potentially being affected (does not count feet)
What are the boundaries for disease activity on the DAS28 score
> 5.1 Active disease.
- 2- 5.1 Moderate disease.
- 6-3.2-Low disease activity.
Less than 2.6 Remission.
Describe the stages of treatment in RA
Aspirin/NSAIDs \+ steroids \+ DMARD 1 \+ DMARD 2 \+ DMARD 3
once in remission - gradually withdraw Tx
What steroid injections can be used in RA?
3 IM injections of 120 mg methylprednisolone every 4 weeks
If fewer than 5 joints involved = Intra-articular injections
What DMARDs are used in RA?
Methotrexate
Sulfasalazine
Hydroxychloroquine
*can be used in combination
What is the drawback of using Hydroxychloroquine alone?
Does not prevent erosions
How is methotrexate used to treat RA?
Start at 15 mg/week with rapid escalation .
Maximum dose 25 mg/week.
Folic acid 24 hours after MTX dose.
Why is regular monitoring required when patients are on DMARDs?
Bone marrow suppression.
Infection.
Liver function derangement.
Pneumonitis in case of methotrexate.
What biological agents are used to treat RA and what feature of the immune response do they block?
Anti TNF agents - Infliximab,Etanercept,Adalimumab
T cell receptor blocker - Abatacept
B cell depletor - Rituximab
IL-6 blocker - Tocilizumab
JAK 2 inhibitors - Tofacitinib
What criteria must be met for a patient to be started on biologic agents?
- Failure to respond to 2 DMARDs including Methotrexate
- DAS 28 greater than 5.1 on two occasions 4 weeks apart.
What is co-prescribed with biologics?
Methotrexate
What infections must be screened for when using biologic agents?
Screen for latent or active TB ,Hep B/C, HIV, Varicella zoster.
What type of vaccine must be avoided in Biologics patients?
Avoid live attenuated vaccines.
What clinical sign is seen in the hands of patients with severe RA?
Swan-neck deformitiy of fingers
ulnar deviation of MCP joints
Boutonniere deformity of the Thumb
What can C1-C2 involvement cause?
Atlanto-axial subluxation and instability
=> when leaning head forward, only atlas moves instead of whole spine
