What is Rheumatoid Arthritis (RA)?
Rheumatoid arthritis (RA) is a chronic inflammatory disease of joints including the soft tissue of joints as well as bone and cartilage. It is considered the most dangerous of the common forms of arthritis because it leads to permament damage to the joints early in the disease. Disability rates are high among sufferers and disability often occurs early in its course.
 

Causes of RA
RA runs in families so there is a genetic component. It is now thought that genetically susceptible people need a variety of internal and external factors to work together to trigger RA.
Risk factors include female sex, age, smoking, race (Native Americans) and certain blood types  - HLA DR4, HLA B0101, HLA B0401.
The fact that changes occur in the blood, and the appearance of other symptoms such as tiredness, loss of appetite and fever show that it is not just a disease of joints: it is a sytemic disease. The immune system is disordered. It may be that RA sufferers have an overactive immune defense system turning on the body's own tissues.
 

How is RA diagnosed?
RA may not show up on Xrays or lab tests in the early stages, so the GP must be alert for the possible diagnosis and make a clinical diagnosis.
Early symptoms and signs:
Often RA starts is in one joint but multiple joints will eventually be affected. The joint will swell, feel hot and be stiff with reduced range of movement. The patient will often feel unwell. The first joints affected are often the wrist, the joint at the base of the finger (metacarpo-phalangeal joint) and the first joint of the finger (proximal interphalangeal joint) .
The onset occasionally is rapid and progressive but mostly it comes and goes at first. The doctor should still be suspicious even if he initial symptoms go away.
If the symptoms start first in the lower back, the doctor should suspect another kind of arthritis, not RA: RA rarely affects the lower spine. Ankylosisng spondylitis affecting the spine is almost always missed at first, often for decades.  AS patients may have negative tests for years and be labled psychoneurotic: by the time changes appear 10 or 20 years later, they are neurotic.
Lab tests: CBC (complete blood count), ESR (Erythrocyte Sedimentation rate), CRP (C Rective protein), Rheumatoid Factor (RF). RF is usually negative, but it should be done as a baseline. The Sed Rate and CRP are measurements of inflammation in the body: the higher the level, the more inflamed something is, but they do not tell you what is inflamed. Acutely Swollen joints and high ESR/CRP are signals for the doctor to be aggressivre in treatment and to make an early referral to a specialist.
Xrays: are often negative at first but form a baseline for progress if the diagnosis is confirmed.
 

Progression of RA
RA can progress rapidly to cause permament damage to joints: the bone surface erodes, cartilage becomes boggy and wears away, the synovial lining of the joint becomes thick, inflamed and stiff.
By two years of diagnosis Xrays show damage in most patients.
If untreated the disease progresses both in the initially affected jointa and eventually in many joints of the body: severe disability may result. Many RA sufferers are unable to maintain employment.
 

Differential Diagnosis:
Other diseases to consider and rule out include SLE (lupus), Psoriatic arthropathy, sero-negaive arthropathies (arthritis that does not show on initial lab work) such as ankylosisng spondylitis, Reiter's syndrome, arthritis associated with Crohn's disease, celiac disease and other bowel inflammations. Just about any arthritis should be considered in the early stages.