Rheumatoid arthritis

Rheumatoid arthritis (RA) RA is the most common inflammatory arthritis characterized by symmetrical and deforming of the small and large joint polyarthritis associated with systemic disturbance and extra-articular manifestations with intermittent exacerbations and remissions The prevalence increases with age , more in female 3:1 male , the RA is uncommon in men under the age of 45, where there is a 6: 1 female excess

Aetiology No single factor has been identified to date Genetic susceptibility is important HLA –DR 4 occurring in 50- 75% of Caucasian patients compared to 20 – 25 % of normal population Female gender is a risk factor No infectious agent has been isolated Presence of immune complexes at site of articular and extra articular lesion

Pathology Swelling and congestion of the synovial membrane due to infiltration of lymphocyte , plasma cell and macrophage with effusion of synovial fluid in the joint place Hypertrophy of the synovial membrane Inflammatory granulation tissue (pannus ) spread over and under the articular cartilage which is progressively eroded and destroyed

Later , fibrosis and bony ankylosis may occur Muscle atrophy with focal infiltration with lymphocyte Subcutaneous nodules consist of central area of fibrinoid material surrounded by palisade of mononuclear cell , similar granulation lesion may occur in the pleura , lung, pericardium and sclera

Clinical features Gradual onset of symmetrical arthralgia and synovitis of the small joints of the hands , feet and wrists . 10 % acute onset 5 % palindromic with recurrent symmetrical acute episodes of J. pain and swelling which last only for few hours or days Moring stiffness more than 1 hour Symmetrical swelling of the MCP and PIP J

Deformities of R.A Specific hand abnormalities include Swan neck deformity , the boutonniere or button hole deformity and Z deformity of the thumb , triggering of fingers and dorsal sublaxations of the ulnar styloid In the fore foot dorsal sublaxation of the MTP J result in cock up deformity , callosities over the MTP head In the hind foot , calcaneovalgus ( eversion ) deformity reflecting damage to the ankle and subtalar J .

Popliteal cyst ( Baker’s ) can occur in combination with knee synovitis and sometimes complicated by rupture which induced by knee flexion lead calf pain and swelling Extra – articular features : anorexia , weight loss and fatigue Generalized osteoporosis and muscle wasting These features occur mainly in sero positive erosive disease especially in men

Cutaneous features : subcutaneous nodules occur in sero positive patients at site of pressure or friction such as extensor surface of the forearm , sacrum , Achilles' tendon and toes Systemic rheumatoid vasculitis in form of nail fold infarct , cutaneous ulceration with skin necrosis

Extra-articular manifestations Occular features Dry eye ( keratoconjunctivitis sicca ) Painless episcleritis ( intense redness , no visual disturbance ) Scleritis ( more serious and sight threatening ) the eyes are red and painful , pupil was irregular due to adhesion ( synechiae ) Corneal melting associated with systemic vasculitis may progress to perforation

Cardiovascular features Asymptomatic pericarditis in 30 % Pericardial effusion , constrictive pericarditis Heart block , cardiomyopathy , coronary artery occlusion or aortic regurgitation

Pulmonary features Fibrosing alveolitis Pleural effusion especially in the men with sero positive , usually small , unilateral and resolved spontineously Rh pulmonary nodule sub pleural and usually multiple , combination of Rh. Nodule and pneumoconiosis is known as Kaplan’s syndrome Bronchitis and Bronchiectasis

Neurological features Entrapment neuropathy (median nerve compression ) , ulnar nerve compression at the elbow , lateral popliteal nerve at the head of the fibula , tarsal tunnel syndrome Symmetrical peripheral neuropathy Mono neuritis multiplex Cervical cord compression result from sublaxation of the cervical spine at the atlanto – axial J or at sub axial level

Haematological features Microcytic iron deficiency anemia due to NSAID Normochromic normocitic anemia , thrombosis due to active disease Felty’s syndrome (spleanomegally , lymphadenopathy , neutropenia , weight loss , skin pegmintation , K C Sicca Long standing deforming sero positive RA Lymphadenopathy localized or generalized due to lymphoma in long standing disease Amyloidosis is a rare complication

Investigations 1- Clinical criteria : Morning stiffness >1 hr Arthritis of 3 or more Js. Arthritis of hand Js . Symmetrical arthritis Rh. Nodules Rh. Factor Radiological features Duration of 6 weeks or more ** Dx of RA is made of four or more criteria

2) Elevated acute phase protein 3) Rh.F present in 60-80 % ( 10 % of normal population ) 4 ) radiographs shows : periarticular osteopenia Marginal non – proliferative erosions

Management Physical rest Passive exercise in acute RA Hospital admission in severe condition ( patient needs intra articular injection , J. splinting , regular hydrotherapy and physiotherapy NSAIDS Prednisolone 7.5 mg /day DMARDS ( single or in combination , used early before radiological changes appears Methotrexate and Sulfasalazine are current first choice

Surgery Synovectomy to relieve pain and prevent tendon rupture Osteotomy Arthrodesis Arthroplasty

Prognosis 5 years survival for the patient with severe disease is 50 % 40 % disabled within 3 years 80 % will be moderately to severely disabled within 20 years and 25 % require large J. replacement

Poor prognosis factors Higher baseline disability Female gender Involvement of the MTP +ve Rh F Disease duration of over 3 months

MCP & PIP arthritis

PIP arthritis

MCP arthritis & wasting of extensor ms.

Wrist & PIP arthritis

Z-deformity & MCP arthritis

Wrist , MCP & PIP arthritis

Ulnar deviation & Z deformity

Swan neck deformity

MCP arthritis , ulnar deviation

Wasting of extensor ms

Piano – glass deformity

Rheumatoid nodules - elbow

Rheumatoid nodules –dorsum of hand

Vasculitis

vasculitis

Osteopenia & dec J. space

Soft tissue swelling

Sclerosis and dec j. space

Joint erosion

Bilateral ulnar deviation of PIP J.

Ulnar deviation of PIP J.