Fibromyalgia: Evaluation and Therapy of a Neuroimmune Disorder

Abstract

Fibromyalgia (FM) is one of the commonest but most enigmatic rheumatologic conditions encountered by the practicing clinician. Difficulties in its diagnosis and successful treatment stem, in part, from the absence of a coherent pathophysiologically based approach to the disorder. Two cases of FM, found in association with connective tissue diseases, are presented, and a novel approach to their clinical evaluation is outlined. In both cases the clinician is encouraged to seek out historical and physical findings suggesting the presence of peripheral nerve lesions akin to those seen in chronic inflammatory demyelinating polyneuropathy (CIDP) and small fiber neuropathy (SFN). The chapter outlines a logical approach to the laboratory evaluation of this situation utilizing electrodiagnostic testing (electromyography and nerve conduction velocities) and skin biopsy-generated epidermal nerve fiber density (ENFD) testing. The results of these evaluative strategies lend weight to the assertion that the patient outlined in Case 1 represents a member of a large subset of FM whose pain is likely to be due, in large part, to the neuroimmune lesion(s) seen in CIDP and SFN. In Case 2 the results of testing suggest that the patient is an example of “pseudofibromyalgia” and has pain originating, in large part, from a diffuse enthesopathy, as might be seen in forme fruste ankylosing spondylitis. The implications of these findings vis a vis these patients’ therapy, and our better understanding of FM in general, are discussed in detail.

He who studies medicine without books sails an uncharted sea, but he who studies medicine without patients does not go to sea at all.

—William Osler, M.D.