Rheumatoid Arthritis is an autoimmune disease that causes chronic inflammation of the joints and tissues around the joints. It also affects the other organs of the body. It is a chronic polyarthritis affecting mainly the peripheral joints, running a prolonged course with worst symptoms and relief with systemic disturbance.
The disease is characterised by-
• swelling of the synovial membrane and periarticular tissues,
• Subchondral osteoporosis,
• erosion of cartilage and bone and
• Wasting of the associated muscles.
Aetiology of Rheumatoid Arthritis :
Aetiology of disease is obscure, but it may arise as a result of number of factors which are as follows:
1. Age: The average age of onset of disease is about 40, but it may occur at all ages. It is less common before puberty.
2. Sex: Females are affected three times more than males.
3. Climate: Previously it was believed that the disease is more common in temperate zones associated with cold & damp but this theory is obsolete now.
4. Heredity: The influence of heredity is not known but a family history of the disease is not infrequently obtained.
5. Infection: Rheumatoid arthritis is not due to invasion of the joints by any organism.
6. Auto-immunity: Presence of abnormal globulins with typical antibodies in blood in high proportion with the histological appearances in the synovium have shown that rheumatoid arthritis may be associated with a derangement of the immune response to exogenous antigens or to antigens derived in the part at least from the patient's own tissues. The presence of these antibodies, in certain conditions react with material derived from a human source; suggest that they may play some role in tissue damage, yet no direct evidence in support of this hypothesis.
7. Endocrine Factors: There is no evidence seen that rheumatoid arthritis arises from any abnormality of the endocrine glands. Suppression of symptoms and signs of inflammation by cortisone and hydro-cortisone is non-specific in nature.
8. Psychological Factors: Rheumatoid arthritis is sometimes precipitated and increased by emotional upset or excessive worry and overwork.
9. Nutrition: There is no evidence that dietetic habits of patient, suffering from rheumatoid arthritis, differs from normal. These patients are often underweight.
Pathology of Rheumatoid arthritis :
• The first change in rheumatoid arthritis is swelling and congestion of the synovial membrane and overlying connective tissue, infiltrated with polymorphs, lymphocytes and macrophages. At this stage the disease is reversible and no permanent damage to the joint occurs.
• Hypertrophy of the synovial membrane occurs and external capsular layer becomes thick.
• Inflammatory granulation tissue is formed, which spreads with patchy destruction of the cartilage under the articular surface.
• Later fibrous adhesions may occur between the layers of granulation tissue across the joint space. These changes are irreversible leads to permanent damage to the joint.
• Irregular contraction of fibrous tissue in the capsule and adoption of a flexion for the relief of the pain, deformity of alignment develop.
• Later fibrosis and even bony ankylosis may occur.
• In disorganised joints, where movement is still possible, secondary osteoarthritic changes occur.
• Effusion of synovial fluid into the joint space occurs during the active phase of the disease.
• With changes osteoporosis occurs in the parts of bones adjacent to the joint margins and atrophy of the associated muscles with round cell infiltration.
• Later the osteoporosis becomes generalised.
• Subcutaneous muscles have a typical histological appearance
• There is a central area of fibrinoid material consisting of swollen and fragmented collagen fibres, fibrous exudates and cellular debris, surrounded by a palisade of radially arranged proliferating mono- nuclear cells. The nodule is surrounded by a loose capsule of fibrous tissue.
Clinical Features of Rheumatoid Arthritis :
• Mostly the onset of disease is insidious. Sometimes (in 10% cases) onset may be acute with fever and quick involvement of many joints.
• For a period of weeks or month before the joint is involved the patient may complaint of:
-Numbness & tingling in the extremities
-Loss of weight
-General debility and rarely
-Rarely transient articular & muscular pain.
• In typical case of rheumatoid arthritis the small joints of fingers and toes are first affected.
• As the disease progresses it affects wrists, elbows, shoulders, ankles and knees.
• In sever cases hip joints are also affected.
• The temporo-mandibular and sterno-clavicular joints are rarely involved.
• Muscular stiffness is a prominent symptom of the disease which is more marked in the morning or after a period of inactivity.
• Swelling of the proximal inter phalangeal joints gives rise to the typical spindle shaped fingers.
• As the disease advances, joint pain and swelling increase with more marked muscular stiffness.
• Muscular atrophy takes place early and becomes a very prominent feature of disease.
• During the active stage of the disease signs of a systemic disturbance are present which are:
-Low grade pyrexia
-Hypo chromic anaemia
-Mild polymorph leucocytosis
-Altered plasma protein pattern (increased globulin & fibrinogen;
• In more advanced cases pain and muscle spasm gives rise to flexion deformities of the joints.
• At first flexion deformities are correctable, but later permanent contractures develop and joints completely disorganised.
• The characteristic deformity in the hands is anterior subluxation of the meta-carpo phalangeal joints & ulner deviation of the fingers.
• In the early phase the disease is characterised by cures and relapses. At this time x-ray examination of the affected joints will show only demineralisation of the bone ends.
• Later as the disease progresses it involve the articular cartilage with narrowing of the joint space and marginal erosions.
• In the late stages, in joints which are still capable of some movement, x-ray examination will show the osteoarthrosis, as a secondary manifestation in the damaged joints.
• The joints which are immobilised by pain & muscular spasm, fibrous or bony ankylosis may take place.
• Subcutaneous nodules appear in 10-20% of patients. The most common site is the extensor surface of the forearm about 2.5cm below the elbow joint. They may also occur over the patella, scapula, sacrum, scalp and along the tendons of the fingers & toes.
• In severe cases amyloidosis may complicate the later stages of the disease.
• Diffuse vasculitis is a common feature of rheumatoid arthritis, in patients with nodules and a positive sensitised sheep cell test.
• Leg ulcers, episcleritis, scleritis, pericarditis, pleurisy and peripheral neuropathy are the extra-articular manifestations of the rheumatoid arthritis.
Differential diagnosis of Rheumatoid arthritis :
In average cases the diagnosis of rheumatoid arthritis is not so difficult but when the disease starts in an atypical manner it will be differentiated from the following diseases:
1. Rheumatic Fever
2. Gonococcal arthritis
3. Reiter's Disease
4. Acute Pyogenic Arthritis
6. Tuberculous Arthritis
8. Psoriatic Arthritis
Examination of synovial fluid :
Examination of synovial fluid may provide valuable information, when infection is suspected fluid should be cultured. In Gout, uric acid crystals may be seen on microscopic examination. Fluid from traumatic or degenerative forms of arthritis is clear, viscid, doesn't clot and contains few cells. In rheumatoid arthritis or pyogenic infection the fluid is of low viscosity, turbid, clots on standing & contains many cells.
Sensitised Sheep Cell Test :
It is a serological test for the diagnosis of atypical forms of rheumatoid arthritis. It is also known as Rose-Waaler Test and is positive in 65-70% cases of rheumatoid arthritis. This test is also positive in Dessinated lupus erythematosis (in 25-30%cases) and Juvenile Rheumatoid arthritis (Still's disease).
Treatment of Rheumatoid arthritis :
As the aetiology of rheumatoid arthritis is not known, treatment must be directed towards the relief of symptoms, the improvement of the patient's general health and restoration of function in the joints damaged by the disease process.
General Measures :
When multiple joints are swollen and painful with the signs of severe constitutional disturbance, such as fever, anaemia, and rapid ESR, the patient should be confined to bed until these sign & symptoms begin to subside. Foot and quadriceps exercises should be performed daily by all patients confined to bed. The general level of physical efficiency should be maintained by the use of suitable exercises. Most patients in acute phase of the disease will have lost weight & the diet should be of high caloric value with ample protein. Additional vitamin is not given if a well-balanced diet containing milk, eggs and fruit is eaten.
Local Measures :
It has been observed that the correct treatment of the inflamed joints may control both local and systemic symptoms of rheumatoid arthritis. The symptoms of inflammation subside more quickly if the joints are left at complete rest for a period of one to two weeks. The application of heat before exercise is useful in relieving stiffness. Physiotherapy is used to supplement active forms of treatment. Wax baths are beneficial in reducing stiffness in the joints of the hands and feet. Residual pain may be eased by radiant heat, infra red rays or shortwave diathermy.
Occupational Therapy is of considerable importance in restoring and conditioning the patient for a return to productive employment.
Drugs given in Rheumatoid Arthritis :
Aspirinis the most valuable anti-inflammatory drug and given in the dose of 4-6g daily. Calcium aspirin should be used when ordinary aspirin is not well tolerated. Paracetamol is less effective in controlling symptoms, but used when aspirin is poorly tolerated in the dose of 6-8g daily.
Phenylbutazone (Butazolidin) is an effective analgesic but like aspirin it has no curative action.
Other anti-inflammatory drugs are Mefenamic acid, flufenamic acid, indomethacin and ibuprofen.
Corticosteroids: The dramatic effects of cortisone in the symptoms & signs of RA are seen but it has been observed that in long term treatment had no advantage over aspirin.
Local use of Corticosteroids : The intra-articular injection of a suspension of hydrocortisone acetate is followed by a reduction of pain and swelling. Duration of relief varies from a few days to two to three weeks.
Extra-articular lesions can be treated by local injection of corticosteroids.
Eye drops of hydrocortisone are valuable in controlling inflammatory conditions of the eyes.
Anaemia in case of RA is treated either orally or parenteraly use of iron.