Clinical and laboratory features of idiopathic inflammatory myopathy

Dr Yves Allenbach is an associate professor in the Department of Internal Medicine and Clinical Immunology and Myology Research Center at Pitié-Salpetriere University Hospital (France).

What clinical features and laboratory test results suggest idiopathic inflammatory myopathy?

Yves Allenbach, MD, PhD: The clinical features that suggest the presence of myositis could be varied. There are 3 domains that can be involved in myositis patients.

There is the muscle weakness, for sure. There are the joints; some patients may have joint pain or synovitis. Another domain that can suggest the presence of myositis is the skin rash, especially if it is compatible with dermatomyositis (DM). The lungs are the last domain. Sometimes patients have a lung disease like cough or dyspnea as the first symptom. Since myopathy could be systemic, skin, joints, and lungs—in addition to muscles—could show symptoms or signs leading to the presence of myositis.

If we think about the clinical data that could suggest the presence of myopathy, the only one is the increase of the creatine kinase (CK) level, I guess. Nothing more.