Introduction
Rheumatoid arthritis is a chronic auto-immune inflammatory arthritis.
In rheumatoid arthritis, the body’s immune system attacks its own tissue, including joints. In severe cases, it attacks internal organs.
- Autoantibodies that are characteristic of RA, including rheumatoid factor (RF) and anti-citrulluninated protein antibodies (ACPA), are present before clinical disease onset.
- It typically affects females more than males.
- It affects all age groups but especially 40yrs and above.
- If untreated or badly managed, it could result in deformities, cardiovascular morbidities and decreased life expectancy
- It is characterized by affectation of small and medium sized joints in a symmetric fashion
- The synovium is the primary site of the inflammatory process, which if untreated leads to irreversible damage to the adjacent cartilage and bone.
- Once RA synovitis is established, a number of amplification mechanisms serve to sustain the process leading to the persistence of the disease.
- Risk factors of RA are genetic such as Shared Epitope of HLA DRBI; environmental such as infective agent parvovirus, Epstein Barr virus, mycoplasma, smoking
Clinical features
- It diagnosis based on the American College of Rheumatology criteria (ACR)
- Lately the ACR and European League Against Rheumatism (EULAR) criteria
- Symptoms include constitutional features such as fever, loss of weight, loss of appetite, fatigue, nausea, anaemia
- Polyarthritis involving especially joints of the hands, elbows, shoulders, feet, knees, hip and temporo-mandibular
- It hardly ever affects joints of the spine except Atlanto-axial joint
- Dryness of the mouth and eyes
- Subcutaneous nodules especially the elbow
- Internal organ involvement may include pleural effusion, interstitial pneumonitis, pericarditis, pericardial effusion, ischemic heart disease, conjunctivitis, hepatoslenomegaly
Differential Diagnosis
- Polyarticular osteoarthritis
- Polyarticular gout
- Systemic Lupus Erythematosus
- Spondyloarthropathy
- Reactive Arthritis
Investigations
- Haematocrit, white blood cell count, ESR, CRP
- Liver function tests (as most of drugs used could be hepatotoxic)
- Cholesterol, triglycerides
- Rheumatoid factors
- Anti Cyclic Citrullinated Peptide
- Imaging
- Plain radiographs especially of the hands and feet to demonstrate erosions
- Ultrasound of the joints to demonstrate synovitis and erosions
- CT scan
- MRI
- Radioisotope
Treatment of Objectives
- To reduce pain and swelling
- To prevent joint destruction and deformities
- To prevent cardiovascular morbidities
Management
- Non-pharmacologic treatment as in osteoarthritis.
- Disease modifying Antirheumatic drugs (DMARDS) are the mainstay and must be started immediately
- NSAIDs are supportive and should be stopped if there is no pain or if any adverse effects
Synthetic DMARDS:
Methotrexate
This is gold standard
- 7.5mg – 25mg orally or SC once weekly
- Administer folic acid or folinic acid to reduce the risk of methotrexate adverse reactions
- Methotrexate is strongly recommended over hydroxychloroquine or sulfasalazine for DMARD naive patients with moderate-to-high disease activity
Sulfasalazine tablets
- 1gm – 3gm daily in divided doses
Hydroxychloroquine sulphate
- 400-600 mg/day orally daily in divided doses
Leflunomide
- 20mg – 30mg daily after loading dose
Azathioprine
- 2-3mg/kg body weight daily.
Cyclophosphamide
In some cases, combination therapy is used:
- Methotrexate+ Sulfasalazine + Hydroxychloroquine or
- Methotrexate + Leflunomide
Biologic DMARD
- This is used according to guidelines if disease activity is still high after synthetic DMARDs has been used
These include
- Anti TNF-
- Etanercept
- 50 mg SC once weekly
- if necessary, methotrexate, glucocorticoids, salicylates, NSAIDs, or analgesics can be continued during treatment with Etanercept
- B Lymphocyte Depletor
- Rituximab
- 1000 mg IV infusion, repeat after 2 week (one course)
- Repeat course q24weeks or based on clinical evaluation (but no sooner than 16 weeks)
- Use in combination with methotrexate
- Premedicate with glucocorticoids 30 minutes before infusion to reduce infusion reaction
- Do not to exceed 1000 mg/dose
- Corticosteroids
- Prednisolone at low doses,
less than 15mg eventually phased out within 6 months; intra-articular steroid
- Prednisolone at low doses,
- NSAIDs
- used only in exacerbation of pain.
Adverse Effects
NSAIDs
- Dyspepsia,
- Peptic ulceration,
- Gastro intestinal bleeding,
- hepatotoxicity,
- fixed drug eruptions.
DMARDS
- Susceptibility to infections,
- Hepatotoxicity,
- Elevated blood lipids,
- Pancytopenia,
- Bone marrow suppression,
- Malignancy,
- Teratogenicity
2021 American College of Rheumatology Guideline for the Treatment of Rheumatoid Arthritis