Rheumatoid arthritis

From Ganfyd

Current revision

Introduction

A chronic inflammatory condition of connective tissue, which is destructive of joints leading to deformity; but with extra-articular manifestations and, in the majority of patients, circulating IgM rheumatoid factor.

Aetiology

Aetiology is uncertain. Prevalence approximately 3%; Female:Male=3:1.

Associations

In some Europeans:

• HLA-DRB1 - possibly by affecting the presentation of autoantigens
• PTPN22 - possibly by modifying T-cell–receptor signal transduction
• TRAF1-C5 - TRAF1 possibly changes signal transduction through TNF receptors, C5 - possibly amplifies complement activation^[1]

In Asians:

• PADI4 - involved in citrullination of proteins
• FCRL3 - Fc receptor-like 3 gene

Other genetic associations:

• STAT4 - presumably via its role in immune differentation pathways - also with SLE^[2] and consistent across races^[3]

Clinical

Symptoms

Insidious onset of symmetrical joint pain, particularly in the small joints of hands, feet and wrists. In advanced disease other joints may become involved but hips are often spared

Signs

• Proximal interphalangeal (PIP) joint swelling gives a spindled appearance.
• Swan neck deformity:
  • hyperextension of PIP
  • flexion of DIP

or the reverse:

• Boutonnière deformity:
  • flexion of PIP
  • hyperextension of DIP
• Swelling of metatarso-phalangeal (MTP) joints broadens the forefoot
• There may be fever, general malaise and night sweats which can occur before the onset of joint symptoms.
• Weight loss
• Ulnar deviation of the fingers give a characteristic deformity

Criteria for Diagnosis of Rheumatoid Arthritis 4 or more of: morning stiffness >1 hour involvement of 3 or more joints involvement of hand and wrist joints symmetrical arthritis subcutaneous nodules positive rheumatoid factor typical X ray changes - erosions, periarticular osteopaenia American College of Rheumatology, 1987

Investigations

• FBC
• ESR
• CRP
• serum rheumatoid factor
• Autoantbodies (for differential diagnosis)
• X-ray

Specialist investigations

A wide range of differential diagnosis is possible. More specialist investigations may be directed towards these, including testing for common viral or other pathogens that cause arthritis in early onset disease or more exotic cutting edge investigations such as autoantibodies to cyclic citrullinated peptide (CCP) which appears to be more specific to rheumatoid arthritis than rheumatoid factor^[4].

Treatment

Medical

• Non steroidal antiinflammatory drugs(NSAIDs)
• Disease modifying antirheumatic drugs(DMARDs)
• Immunosuppressive drugs
  • Methotrexate is agent of choice
• Immunomodulatory drugs
  • Biologics. Adalimumab and rituximab have best evidence for clinical effectiveness

• Joint injections

Surgical

• Surgical removal of local areas of diseased synovium
• Excision of subluxed metatarsal heads
• Arthroplasty of hip. knee, shoulder or elbow joints, or the small joints of the hands

References