Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune disease that can cause chronic inflammation of the joints and other areas of the body.

Incidence:

·         Female to male ratio 3: 1

·         Peak age incidence between 20 – 40 years

·         25 % of RA patients need large joint replacement.

Etiology:

The cause of rheumatoid arthritis is unknown. The following are the risk factors.

·         Genetic factors because it is usually associated with HLA – DR4 in whites and DR1 in Indo – Pak.

·         Female gender is a risk factor and this susceptibility is increased post – partum and by breast feeding.

·         Cigarette smoking is also a risk factor.

Pathophysiology:

There are three main pathological characteristics.

      i.        Chronic inflammation

     ii.        Granuloma formation

    iii.        Joint destruction

RA is disease of synovial membrane. There is swelling and congestion of synovial membrane and the underlying connective tissues, followed by infiltration by lymphocytes (especially CD4 T cells), plasma cells and macrophages. The synovial membrane then proliferates and grows out over the surface of cartilage, which causes the erosion and destruction of the cartilage.

Clinical features:

·         Joint pain

·         Morning stiffness

·         General symptoms: Fatigue and malaise

·         Deformities: In advance stage of RA.

Deformities of hand and forearm:

Swan neck deformity: Characterized by hyperextension at the proximal interphalangeal joints and fixed flexion at the distal interphalangeal joints.

Boutonniere or Button hole deformity: Characterized by fixed flexion of the proximal interphalangeal joint and extension of the distal interphalangeal joint.

Z deformity of thumb: Characterized by hyperextension of the first interphalangeal joint and flexion of the firs metacarpophalangeal joint with a consequent loss of thumb mobility.

Ulnar deviation

Deformities of foot and knee:

Cock up deformity: Dorsal sublaxation of metatarsophalangeal joint.

Baker’s cyst: Cyst (extension of inflamed synovium) in popliteal space. High pressure generated by flexion of knee can cause rupture of cyst into calf leading to calf pain, swelling and tenderness.

Criteria for the diagnosis of RA:

Diagnosis of RA is made with four or more of the following.

      i.        Morning stiffness (> 1 hour)

     ii.        Arthritis of 3 or more joints

    iii.        Arthritis of hand joints

    iv.        Symmetrical arthritis

     v.        Rheumatoid nodules

    vi.        Rheumatoid factor

   vii.        Radiological changes

  viii.        Duration of symptoms ≥ 6 weeks

Extra –articular features:

Lungs:

o    Pleural effusion

CNS:

o    Cervical cord compression

o    Peripheral neuopathy

Ocular:

o    Scleritis

o    Keratoconjunctivitis

Musculoskeletal:

o    Muscle wasting

o    Tenosynovitis

o    Bursitis

Cardiac:

o    Pericarditis

o    Myocarditis

o    Endocarditis

Lymphatic:

o    Spleenomegaly

o    Feltey’s syndrome

Investigations:

o    ↑ ESR

o    ↑ C – reactive protein

o    RA factor is present in about 70% of cases.

o    X – Ray to establish diagnosis and monitor disease damage.

Management:

General measures:

·         Educate the patient

·         Control pain: Paracetamol 1 g TDS

·         Exercise

·         Joint protection: If obese then weight loss

Specific treatment:

DMARDs (Disease Modifying Anti-Rheumatic Drugs): 

o    Methotrexate

o    Sulfasalazine

o    Azathioprine

o    Hydroxychloroquine

o    Leflunamide

o    Gold

o    Penicillamine

Biological DMARDS:

Anti – TNF therapy:

o    Inflixemab

o    Adalimumab

o    Etanercept

Steroids:

Low dose

Surgery:

o    Synovectomy

o    Arthrodesis

• Arthroplasties