Myositis (A Tough One)

Myositis is one of those diagnoses that we are still classifying. Two decades ago, there were only a few classes of myositis, but with the discovery of more and more myositis specific antibodies (MSA), the classification of myositis continues to evolve. Even today, there is disagreement between various authorities as to what belongs where and what differs from what. The relatively rare incidence of myositis only adds to the confusion, since the ability to run meaningful studies to shed light on our understanding of myositis is limited by the paucity of cases of myositis. At the same time, the discovery of myositis specific antibodies has transformed the disease, since we can now make specific diagnoses based on the presence of antibodies unique to a particular form of the myositis. Providers, because of the lack of exposure and hence the lack of experience with the disease, frequently mistake myositis for other more familiar conditions, leading to sometimes dire consequences for the recipients of the diagnoses made. Myositis can have a serious impact on the ability of people to perform their activities of daily living and, at times, can be a crippling disease. Not only does it occur spontaneously, but it can be the harbinger of cancers and other rheumatologic diseases. Myositis is one of the “great pretenders,” and undoubtedly, there are staggering revelations and surprises waiting in the future for providers treating myositis.