Arthritis is an inflammation of joint. It is characterized by pain, swelling and limitation of joint movement.
The cause may be purely a local pathology such as pyogenic arthritis, or a more generalised illness such as Rheumatoid Arthritis.
Today we will discuss about Rheumatoid Arthritis.
Rheumatoid Arthritis is a chronic non-suppurative inflammatory of the synovial joint diagnosed as per the criteria laid down by American Rheumatism Association in 1987.
Morning stiffness. Swelling of three or more specified joints. Swelling of joints in the hand and wrist. Symmetrical swelling. Rheumatoid nodule. Rheumatoid factor positive. X-Ray change-erosion or unequivocal peri-articular osteopenia.
Causes Of Rheumatoid Arthritis
The exact causes is not known. Following factors have been thought to play a role in causation of the disease.
If four or more of these are present, it is Rheumatoid Arthritis.
A genetic predisposition is strongly suspected because of certain histocompatibility markers associated with it (HLA-drw4/HLA-DRI).
Agent such as mycoplasma, clostridium and some viruses have been implicated in its etiology.
It is now belived that rheumatoid arthritis results from exposure of a genetically predisposed individual to some infection agent.
This leads to autoimmunity and formation of immune complexes with IgG antibodies in the serum.
These immune complexes are deposited in the synovial membrane and initiate a self perpetuating chronic granulomatous inflammation of the synovial membrane.
State of Rheumatoid Arthritis
1- Potentially reversible soft tissue proliferations- In this stage, the disease in limited to the synovium.
No destructive change can be seen on x- ray.
2- Controllable but irrepressible- Soft tissue destruction and early cartilage erosion x-ray shows a reduction in the joint space, but outline of the articular surface maintained.
3- Irreversible soft tissue and bony change- The pannus ultimately destroys the articular cartilage and erodes the sabchondral bone.
The joint become ankylosed usually in a deformed position (fibrous ankylosis). It may be subluxation or dislocated.
Associated changes- In rheumatoid arthritis there is something evidence of diffuse vasculitis.
The most serious lesions occur in the arterial tree, which may be mild non- necrotising arteritis, or sever and fulminant arteritis anki. To polyarteritis nodosa. The latter is fatal.
Clinical features- It occurs between the age of 20 to 50 years. Women are affected about 3 times more commonly than men.
An acute, symmetrical polyarteritis- Pain and stiffness in multiple joints particularly in the morning, mark the beginning of the disease.
This may be followed by Frank symptoms of articular inflammation.
The joints affected most commonly are the metacarpophalangeal joints, particularly that of the index finger.
Other- The onset may be with fever, the cause of which cannot be established (PUO), especially in children.
Sometimes, visceral manifestation of the disease such as pneumonitis, rheumatoid nodules etc. May antedate the joint complaints.
On examination, one finds swollen boggy joints as a result of intra-articular effusion, synovial hypertrophy and oedema of the peri articular structures.
The joint may be deformed joint of the hand show typical deformities. There may be severe muscle spasm.
Range of motion of the joints may be limited. In later stage, the joint may be subluxated or dislocated.
There may be fever, rash and signs suggestive of systemic vasculitis. The rash in rheumatoid arthritis is typically non-pruritic and maculo- popular on the face, trunk and extremities.
Extra- articular manifestation of rheumatoid arthritis- Although, rheumatoid arthritis is primarily a chronic polyarthritis, extra articular manifestation are very common, and sometimes govern the prognosis of a case.
Radiological examination- This consist of X- Ray of both hand and of the affected joints.
Following features may be present
Reduces joint space
Erosion of articular margins
Juxta- articular rarefaction
Soft tissue shadow at the level of the joint because of joint effusion or synovial hypertrophy.
Deformities if the hand and fingers.
Blood- It shows the following changes
Low haemoglobin value
Rheumatoid factor- This is an auto antibody directed directed against the fc fragments of immunoglobulin G (IgG).
RF can belong to any class of immunoglobulins that is IgG- RF, IgM-RF, IgA- RF, or IgE- RF, but commonly done test detect only the IgM type of RF.
It can be detected in the serum of the patient.