Rheumatoid Arthritis Flashcards
Definition?
SYMMETRICAL, inflammatory arthritis, mainly affecting the PERIPHERAL, synovium joints; if untreated, it can lead to joint damage and irreversible deformities (erosion), resulting in loss of function and increased morbidity and mortality
Occurrence?
- Can affect both sexes but WOMEN are affected 3X
* Can affect any age group
Other problems assoc. ?
Increased CV risk
Damage to nerves
Cause and triggers?
Antigen is unknown but it is HLA-DR4 mediated
Potential triggers inc. infections, stress and CIGARETTE SMOKING
Variability?
Severity and course depend on genetic factors and the presence of auto-antibodies (like anti-CCP, which increases severity and progression)
Examples of affected joints?
Any joints lined with synovium (AKA synovial membrane), e.g: • Hand and wrist • Elbows • Shoulders • TMJs • Knees • Hips • Ankles • Feet • Joints of C1/C2
Pathogenesis of RA?
Unknown antigen is presented to a naive T cell; this leads to eventual macrophage activation
Cytokines have a variety of effects, inc. B cell activation leading to auto-antibody production
How does joint destruction occur?
Cytokines cause osteoclast activation, which resorb bone and cause erosion and inhibition of cartilage cells
Synovial cells cause neovascularisation; this results in PANNUS formation (a fibrovascular tissue over the joint surfaces) which increases the blood supply and allows recruitment of more inflammatory cells
Two main types of inflammation in RA?
Synovitis
Tenosynovitis (as synovium also lines tendon sheaths and this can cause tendon rupture)
Both cause SWELLING and PAIN
Early RA definition? Importance?
Less than 2 years since symptoms onset; the first 3 months is the therapeutic window of opportunity, as the disease process can be modified and established disease can be prevented
Current classification criteria for RA?
PICTURE 2
Why is arthritis of < 6 weeks not awarded a point?
This may have been self-limiting; RA is chronic
What does diagnosis of RA involve?
- History and clinical examination
- Routine blood testing for anaemia of chronic disease, raised platelets
- Inflammatory markers (CRP, ESR/plasma viscosity)
- Auto-antibodies
- Imaging (X-ray, US scan, MRI)
Clinical features of RA?
- Prolonged morning stiffness (>30 mins), due to increased synovial fluid viscosity
- Inv. of small joints of hands and feet (RA often spares the distal interphalangeal joints)
- Symmetric distribution
- Positive compression tests of MCP and MTP joints (if there is pain on compression/ squeezing)
Variable clinical presentation of RA?
- PIP, MCP, wrist and MTP synovitis
- Monoarthritis at the start but this EVENTUALLY progresses to symmetric polyarthritis
- Tenosynovitis and trigger finger (defect in tendon causes a finger to jerk or snap straight when the hand is extended)
- Carpal tunnel syndrome (compression of median nerve due to swelling)
- Polymyalgia rheumatica (inflammation of muscles around the shoulders, neck and hips)
- Palindromic rheumatism (rare episodic form of RA, where symptoms disappear between attacks; 50% progress to full RA)
- Systemic symptoms (due to systemic inflammation), e.g: weight loss, night sweats
- Poor grip strength
What is one of the first manifestations of RA?
Extensor carpi ulnaris tenosynovitis
Auto-antibodies in RA?
Not all patients have these so a -ve result does not rule out RA:
• Rheumatoid factor, i.e: rheumatoid IgM
• To cyclic cirtullinated peptide (anti-CCP antibodies)
Both have a moderate sensitivity but anti-CCP has a much higher specificity
Describe the presence of anti-CCP antibodies
Can be present several years prior to articular symptoms and are assoc. with current/previous smoking; they remain +ve despite treatment
They are more likely to be assoc. with EROSIVE DAMAGE
Advantages and disadvantages of plain X-rays in RA?
Advantages:
Cheap and reproducible
Disadvantage:
Absence of findings in early disease
Signs of RA on X-ray?
- Soft tissue swelling
- Erosions
- Loss of the joint space
- Periarticular osteopaenia (loss of bone density around the joint)
Locations that often shows first RA changes on X-ray?
5th MTP joint
Ulnar styloid
Advantages of US scan?
Increased sensitivity for synovitis in early disease and this is superior to examination
Detects more MCP erosions than plain X-ray, in early RA
Useful in making treatment changes
Advantages of MRI scans?
- Bone marrow oedema on MRI is assoc. with inflammatory joint disease and may be a forerunner of erosion
- Integrity of tendons can be assessed
- Can distinguish synovitis from effusions
- Can detect erosions earlier
- Can be used to monitor disease activity
Disadvantages of MRI scans?
Limited by cost
What scoring system is used to assess disease activity?
DAS 28 - assesses 28 joints; how many are tender and how many are swollen?
Interpreting DAS28 scores?
> 5.1 : active disease
- 2- 5.1 : moderate disease
- 6-3.2 : low disease activity
< 2.6 : remission
What is the aim of RA treatment?
Push the patient into remission
Management of RA?
Early treatment with disease-modifying, anti-rheumatic drugs (DMARDs)
Use of NSAIDs and steroids as adjuncts only (bridging therapy), as DMARDs can take 6 weeks to work)
Patient education
Reason for steroid use?
Improve RA symptoms and reduce radiological evidence of damage
How are steroids used?
Short, sharp courses in combo with a DMARD (not to be used solitarily)
Can be given orally/injections/IM
Examples of DMARDS?
• Methotrexate
• Sulfasalazine
• Hydroxychloroquine (does not prevent erosions)
These can be given as triple therapy
- Leflunomide
- Gold injections, penicillaemina, azathioprine, etc
RA treatment pyramid?
PICTURE 3
Describe methotrexate use
Start at 15 mg/week with rapid escalation, with a max of 25 mg/week
Folic acid must be given 24 hrs after MTX dose
How is palindromic RA treated?
Hydroxychloroquine
Risks with methotrexate?
Allergic reaction
Pneumonitis
Bone marrow suppression
Hepatotoxicity
Cautions with methotrexate?
Advise effective contraception
Regular blood tests
Avoid in patient with pre-existing lung disease, as pneumonitis on top of another disease would have a higher mortality; do a base-line CXR
Avoid Sulfasalazine in septrin allergy and G6PD deficiency
Examples of biologic agents?
Anti-TNF agents: Infliximab, Etanercept, Adalimumab,
Certolizumab, Golimumab
T-cell receptor blocker: Abatacept
B cell depletor: Rituximab
IL-6 blocker: Tocilizumab
JAK 2 inhibitors: Tofacitinib
Guidelines for use of biologic agents?
Used if there is a failure to respond to 2 DMARDs, inc. Methotrexate and DAS28 > 5.1, on two occasions 4 weeks apart
Methotrexate therapy is CO-PRESCRIBED
Must screen for latent or active TB, Hep B/C, HIV, Varicella zoster
Avoid live attenuated vaccines
What is remission?
Absence of signs and symptoms of significant inflammatory arthropathy
Complications of untreated RA?
Joint damage and deformities:
Boutonniere deformity of thumb
Ulnar deviation of MCP joints
Swan-neck deformity of fingers
Atlanto-axial subluxation (C1 and C2 are linked by the odontoid process and bones can move excessively and compress the spinal cord; if the person has neck pain, do an X-ray
PICTURE 4
