Two Scleroderma Patients with Differing Patterns of Muscle Disease

Abstract

Systemic sclerosis (SSc or scleroderma) occurs alone or, on occasion, in association with features of another connective tissue disease such as polymyositis/dermatomyositis, systemic lupus erythematosus, or rheumatoid arthritis. Many SSc patients have myalgia which may be difficult to distinguish by history from arthralgia. Most have pain on motion of the shoulders and hips but do not have objective weakness of these muscle groups or laboratory abnormalities suggesting an inflammatory myopathy. In this circumstance, it is unlikely that progressive proximal muscle weakness will occur during the course of the disease and typically no anti-inflammatory or immunosuppressive therapy is indicated. In contrast, some SSc patients have classic inflammatory myopathy, in which case the term “overlap syndrome” is used. The most frequent SSc overlap is with either polymyositis (PM) or dermatomyositis (DM). Within the broad category of SSc-PM/DM overlap syndromes there are distinctive patient subsets which can be recognized by their clinical features, internal organ involvements, laboratory abnormalities, and immunologic findings. It is important to recognize and treat myositis, as failure to do so may result in irreversible damage of skeletal muscle and proximal muscle weakness with disability.