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Arthritis and Rheumatism

Difficulty in diagnosing

06/09/2004

Question:

Why is it so diificult to diagnose connective tissue diseases? I have many clinical symptoms of a connective tissue disease-cyanotic fingers and toes, curving fingers, a rash on my cheeks, spider veins which keep spreading, swollen knees, ankles, feet and hands and pain in those joints and my neck and shoulders. I have had several ANA panels but none of them have any significant results, however, my CRP has been elevated for the past 2 years and continues to climb and my white count is always elevated (13-15). Does diagnosis always depend on positive blood tests or are clinical signs significant? My GP is great and thinks I have a connective tissues disease, but the specialists seem generally disinterested.

Answer:

The short answer to your question is that the diagnosis of connective tissue diseases is based on a combination of clinical features (signs and symptoms) and lab tests. It is certainly possible to have a connective tissue disease with negative lab tests. Approximately 15% of patients with rheumatoid arthritis have a negative rheumatoid factor (RA) test and approximately 5% of patients with systemic lupus erythematosus (SLE) have a negative anti-nuclear antibody (ANA) blood test. Also, patients with some connective tissue diseases, such as the vasculitides (inflammatory blood vessel diseases) usually have negative RAs and ANAs. The long answer is that connective tissue diseases are less common than a lot of other diseases that share some of their features. This is especially true for older patients, who often have skin, joint, blood, lung, kidney, nervous system and heart problems that may be caused by multiple diseases. For example, cyanotic fingers and toes may be caused by atherosclerosis or congestive heart failure; swollen and painful joints may be caused by non-inflammatory types of arthritis, such as osteoarthritis; swelling in the ankles and feet may be caused by heart disease, kidney disease, or drugs; and rashes on the face and spider veins may be caused by many years of excessive sun exposure. Elevated CRP and white blood count (and erythrocyte sedimentation rate - ESR- if that has been performed) usually indicate a problem, but are not very specific. For example, they may reflect infection or malignancy in addition to connective tissue disease. Generally, the more elevated the ESR, CRP, or white count, the greater the concern. Usually SLE is associated with a reduced, rather than an elevated white count. Often the specific characteristics of the patient (age, sex) and the patient`s problem(s) (appearance of rashes, x-rays of joints, general physical exam, other lab tests) are required to make a diagnosis. If you have not already seen a rheumatologist and a dermatologist, it might be a good idea to see them. If you have already seen one or more of these specialists, these factors may have already been considered and it may have been decided that disorders other than a connective tissue disease are the more likely explanation for your problems.

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Response by:

Fred Finkelman, MD
Director, Division of Immunology
College of Medicine
University of Cincinnati