Inflammatory myopathies are a large group of disorders associated with an inflammatory response targeting skeletal muscle. Treatment hinges on the use of evolving immunotherapies and diagnostic tools to quickly identify inflammatory myopathy, initiate appropriate therapy, and exclude underlying malignancy or infection of other organs.

In this episode, Katie Grouse, MD, FAAN speaks with Anthony A. Amato, MD, an author of the article "Idiopathic Inflammatory Myopathies" in the Continuum® October 2025 Muscle and Neuromuscular Junction Disorders issue.

Dr. Grouse is a Continuum® Audio interviewer and a clinical assistant professor at the University of California San Francisco in San Francisco, California.

Dr. Amato is the Brigham and Women's Hospital Distinguished Chair in Neurology and the director of neuromuscular research at Mass General Brigham, and is a professor of neurology at Harvard Medical School in Boston, Massachusetts.

Additional Resources

Read the article: Idiopathic Inflammatory Myopathies

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Full episode transcript available here

Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum. Thank you for listening to Continuum Audio. Be sure to visit the links in the episode notes for information about earning CME, subscribing to the journal, and exclusive access to interviews not featured on the podcast.

Dr Grouse: This is Dr Katie Grouse. Today I'm interviewing Dr Anthony Amato about his article on idiopathic inflammatory myopathies, which he wrote with Dr Kian Salajegheh. This article appears in the October 2025 Continuum issue on muscle and neuromuscular junction disorders. Welcome to the podcast, and please introduce yourself to our audience.

Dr Amato: Thank you. And I am Tony Amato. I'm in Boston at Mass General Brigham.

Dr Grouse: It is a distinct pleasure to have you here with us today, and I'm really excited to talk with you about your article. I thought it was a fantastic overview of the subject. And I'd like to start by asking what you hope will be the key takeaway for those who are reading this article.

Dr Amato: I think it's kind of basic: how to make a diagnosis, describe about the inflammatory myopathy as approach to, again, diagnosis, and then a little bit on pathogenesis, which… and kind of leading to the treatments, and hopefully we'll have more treatments based on the distinct pathogenesis in the future.

Dr Grouse: Can you give a brief overview of the categories of inflammatory myopathies you reviewed in your article?

Dr Amato: So, I mean, the major inflammatory myopathies, radiopathic inflammatory myopathies, are dermatomyositis, antisynthetase syndrome, immune-mediated necrotizing myopathy, inclusion body myositis, and polymyositis. Now, that's been a big change, as you know. I mean it used to be, you know, we all started off it was dermato or poly. But I've kind of made a name for myself- a bad name for myself in the early 2000s saying, I'm not sure there's much of a thing called polymyositis. I think it's a hodgepodge and it's not distinct. And that's come to be, now most of those cases are- now we find out having antisynthetase syndrome or necrotizing myositis or IBM.

Dr Grouse: Could you walk us through your diagnostic approach with a patient in your clinic presenting with symptoms that are suspicious for inflammatory myopathy?

Dr Amato: So, you want to really make sure that they have inflammatory myopathy as opposed to some other kind of myopathy, a muscular dystrophy, for example. Taking family history first is going to be important, clueing in are they really weak or what they're complaining of is fatigue or muscle pain? Are they feel weak but what they really are complaining of is stiffness and rigidity from parkinsonism, or they have a sensory ataxia so they can't modulate? I want to know about other organ system involvement. Do they have a rash? Do they have joint swelling and pain that you might see with arthritis? Do they have shortness of breath that you might see with interstitial lung disease or ventilatory muscle weakness? Or do they have a cardiomyopathy? What kind of weakness do they have? Is it proximal weakness in the arms or legs? Getting out of a chair, climbing stairs. Do they have problems lifting their arms over their head---so, proximal weakness---or do they have more problems with grip, finger flexion, holding a pen, tripping? Do they have swallowing problems? Do they have ocular problems? So that's the big history on the exam. Again, I'm looking for pattern of involvement. So, on my exam, is there atrophy or weakness in muscles---you know, fasciculations---which would take it out of the motor? Is it mainly proximal? Is it distal? Again, is there ocular bulbar involvement? Is it symmetric, particularly in, like, the IBM? Most of the other inflammatory myopathies are going to be mainly and proximal and mainly symmetric. IBM is different, and that the- at least in the hands it's more distal, and it's finger flexors. So, you're looking at flexing the tips of the fingers, you're looking at the forearms, best looked at in a semipronated position to see if it's atrophied. And that leads you to an IBM if you see that. So that's the main things on exam.

Dr Grouse: That's a really helpful overview. I was wondering, in earlier training days, the convent