Over the last
40 years of my practice, I find that rheumatoid arthritis is the most
common connective tissue disorder. For every 20 patients of rheumatoid
arthritis which I see, I see only one patient of either SLE, polyarteritis
nodosa, temporal arteritis, PMR, scleroderma, spondylo arthropathy,
reactive arthropathy, Behcet’s Syndrome or polymyositis.
Infact, this is very often a bedside clinical diagnosis in a patient
of any age. Bilateral pain occurs in more than 4 or 5 joints, which
include the wrist, the metacarpophalangeal or proximal interphalangeal
joint. The early morning symptom of stiffness, which lasts for half
an hour to one hour often confirms the diagnosis. Ofcourse, the diagnosis
should be made in patients, where the symptoms have lasted for more
than 4-6 weeks. This will exclude arthalgia seen in viral illnesses.
The elevated ESR is the only blood test, which will be positive and
though a non-specific test, it confirms the diagnosis in the above
situations.
Coming to a specific test for rheumatoid factor, earlier we used to
ask for Rose Waaler Test to diagnose
this factor. However, this was a very erratic test. It was then replaced
by the latex fixation test, which is being conducted in modern laboratories
even today. The modern laboratories have started doing this test by
nephelometry, which is the most accurate test to demonstrate the presence
of rheumatoid factor. Unfortunately, this factor becomes positive
after many months or years of disease in many patients. And yet, if
negative, rheumatoid arthritis should not be excluded. Viceversa,
there are many patients of rheumatoid arthritis in our country, having
a mild form of the disease, in whom a remission can take place occasionally,
or who respond very well to the modern line of treatment. Such patients
may never show a blood test report of a positive rheumatoid factor.
Recently a more sensitive test i.e. Anti CCP test is available to
diagnose rheumatoid arthritis, which is much more sensitive than demonstration
of a rheumatoid factor.
The situation in systemic lupus erythematosus (SLE) is different.
In SLE, the blood ANA test must be positive and a negative blood test,
for all practical purposes excludes SLE. But a final definite diagnosis
will only depend on a positive anti DNA antibody test. Unfortunately,
though this test is very specific for SLE, it could be negative in
the case of a straightforward patient.
Ex. Hon. Physician, Jaslok Hospital and Bombay Hospital,
Mumbai, Ex. Hon. Prof. of Medicine, Grant Medical College and JJ Hospital,
Mumbai 400 008.
