Rheumatoid Arthritis(RA)

Dr. Gehan Mohamed

Learning objectives:

At the end of this lecture the student should be able to :

understand definition,genetic predisposition of RA. Discuss pathophysiology, clinical features of RA. Identify Diagnostic Criteria ,Laboratory Features and

bad prognostic Features of Rheumatoid Arthritis.

RA

Systemic inflammatory autoimmune disorder

Age incidence : 40-70 years of age

Genetics

Patients which have HLA-DRB have Increased risk for : RA development. Increased joint damage Increased joint need for surgery

Pathophysiology

Role of Immunolog in RA Macrophages:

Produce cytokines Cytokines (TNF-α) cause

systemic features Release chemokines recruit

PMNs into synovial fluid/membrane

TNF-α & IL-1: Proliferation of T cells Activation of B cells Initiates

proinflammatory/joint-damaging processes

TH-1 cells: Mediate disease processes Activate B cells

B cells: Release cytokines Plasma cells that produce

Ab

Osteoclasts induce: Bone erosion Juxta-articular & Systemic

osteoporosis

Pathophysiology

Swelling of Synovial lining Angiogenesis

Pannus formation in form of : Synovial thickening/hyperplasia Inflammatory vascularized tissue Generation of Metalloproteinases

Cytokine release Infiltration of leukocytes Change in cell-surface adhesion molecules & cytokines Destruction of bone & cartilage

Sequence of events :

Proliferation of synovial membrane cells with inflammatory cell infiltrate

Destruction of joints Disability

Diagnosis:1- clinical criteria2- investigations

1- Diagnostic Criteria

Symmetric peripheral polyarthritis Morning Stiffness >1 hour Extraarticular manifestations Rheumatoid nodules

Symmetric Peripheral Polyarthritis 3 or more Joints for >6 weeks Intermittent or Migratory involvement

Small Joints Hands & Feet Peripheral to Proximal

Leads to Deformity & Destruction of Joints Erosion of cartilage and bone

Stiffness Morning or after Prolonged Inactivity Bilateral > 1 hours

Reflects severe joint inflammation Better with movement Pain with pressure to joint Pain with movement of joint Swelling due to hypertrophy of synovium Effusion Hottness Redness

Physical Exam Decreased grip strength Carpal tunnel syndrome(condition

characterized by pain and numbing or tingling sensations in the hand and caused by compression of a nerve in the carpal tunnel at the wrist.

Ulnar deviation Boutonniere/Swan neck deformities Extensor tendon rupture

Extraarticular Involvement

Myalgia, fatigue, low-grade fever, weight loss, depression.

Anemia Rheumatoid nodules Pleuropericarditis Neuropathy

Scleritis Splenomegaly Vasculitis

Rheumatoid Nodules

Extensor surfaces elbows

Very Specific Only occur in ~30% Late in Disease

Investigations

Arthrocentesis

Confirm diagnoses Differentiate between inflammatory & noninflammatory Labs:

White blood cell count if WBC >2000/µL indicates inflammatory arthritis

Gram stain & Culture

Arthroscopy Evaluate ligamentous & cartilaginous integrity Biopsy Infection: aspirate thick

Rheumatoid arthritis : showing inflammatory cell infiltrate in the synovium

Laboratory Features

Rhumatoid Factor 70-80% of pts.

- Lab manifestations up to 10 years before clinical

- IgM or IgG - If IgM+ve : more severe disease & poorer

outcome.

Overlap with Hepatitis C Virus. Acute Phase reactants

ESR, CRP monitoring disease activity

Radiology

Evaluate disease activity & joint damage

Bony decalcification

Radiological Studies

Plain Films Bilateral hands & feet

Color Doppler U/S & MRI Early signs of damage i.e. Erosions Bone Edema - even with normal findings on

radiography

DiseaseSeverity

Arthralgias >3 inflamed joints Mild functional limitation Minimally elevated ESR & CRP No erosions/cartilage loss No extraarticular disease

Mild Disease

Moderate Disease

6-20 Inflamed joints Moderate functional limitation Elevated ESR/CRP Radiographic evidence of

inflammation No extraarticular disease

Severe Disease

>20 persistently inflamed joints Rapid decline in functional capacity Radiographic evidence of rapid

progession of bony erosions & loss of cartilage

Extraarticular disease

bad prognostic Features

RF +ve Early development of multiple inflamed joints

and joint erosions Severe functional limitation Female HLA epitope presence Lower socioeconomic status & Less education Persistent joint inflammation for >12 weeks

Differential diagnosis of arthritis

Seronegative polyarthritis Psoriatic arthritis Osteoarthritis SLE Paraneoplastic syndrome Crystal-induced arthritis

Tophaceous gout Pseudogout