The Perspective of Neurology in Regard to Polymyositis

THROUGH several years in the neurologic sections of the Mayo Clinic we have encountered cases which have resembled one another in certain features. Yet they have defied accurate diagnostic classification. These cases have been characterized by relatively rapid development of symmetric weakness, chiefly of the proximal muscles of the extremities. Our frustration led us to adopt diagnostic aids not generally used. Of these, more later; the data obtained have been correlated and the clinical entity, polymyositis, is now being recognized with increasing frequency. The importance of this lies in the clinical impression, not yet proved, that treatment with cortisone is of value. “Polymyositis” is a term distinguished by the ambiguity which surrounds its use. In the past it has had at least two meanings. At present it seems to be developing another. In the narrowest sense, “polymyositis” has been descriptive of specific alterations in the histologic picture of muscle. More broadly, the term has been taken in preference to “dermatomyositis,” provided the cutaneous lesions which characterize the latter illness were absent. Finally, it seems to me that “polymyositis” may prove to be the most appropriate term to designate the similar muscular component which is found in a group of related but dissimilar disorders, the so-called collagen diseases.