10:47 AM

Diagnosis Detective: Untangling the web of myositis and its mimics

Healio Rheumatology reports on the mimics of myositis according to experts including HSS rheumatologist David R. Fernandez, MD, PhD.

“The closest mimics of myositis are those illnesses characterized by proximal muscle weakness, myopathy and elevated creatine kinase (CK), including inclusion body myositis (IBM) and limb-girdle muscular dystrophy (LGMD) like facioscapulohumeral dystrophy or dysferlinopathy,” explained Dr. Fernandez.

While there are significant challenges presented by these conditions and the myopathies they mimic, Dr. Fernandez suggested that the mimics fall into two broad categories. “The most common referrals to me that are not myositis take one of two forms: either they are related to abnormal elevation of muscle lab tests, such as CK, or they are related to new onset weakness.”

According to Dr. Fernandez, clinicians should carefully examine the patient history for clues that show deviations from established myositis symptoms. He stressed that weakness from myositis often takes a symmetric, proximal form. Regarding diagnostic criteria specific to mimics, Dr. Fernandez noted excessive pain, atypical features like cramping, early or localized atrophy, localized weakness, stiffness and isolated gait issues, prominent ocular symptoms like diplopia, paresthesia, numbness or fasciculations. “Lastly, clinicians should always be concerned when patients are not responding to therapy,” he said. “Whenever that happens, reconsidering the diagnosis is a valuable place to start.”

Read the full article at Healio.com/news/rheumatology.