American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the second-line therapy for severe inflammatory myopathies that do not respond to glucocorticoids?

1. Rituximab

2. Azathioprine

3. Intravenous immunoglobulin (IVIG)

4. Mycophenolate mofetil

The correct answer is: Intravenous immunoglobulin (IVIG)

Severe inflammatory myopathies, such as dermatomyositis and polymyositis, often begin with glucocorticoid therapy as the first line of treatment. When patients do not respond adequately to glucocorticoids, the management of these conditions requires alternative treatment strategies. Intravenous immunoglobulin (IVIG) is recognized as a second-line therapy in these cases. IVIG consists of pooled immunoglobulin G (IgG) extracted from the plasma of thousands of donors, which exerts immunomodulatory effects. It can be particularly beneficial for patients with refractory inflammatory myopathies, not only providing immunosuppressive benefits but also helping to improve muscle strength and reduce muscle inflammation. IVIG's effectiveness stems from its ability to neutralize pathogenic autoantibodies and modulate various immune functions, leading to a decrease in inflammation and improvement in clinical symptoms. It is often considered when there is a lack of response to glucocorticoids or when patients experience significant side effects from long-term corticosteroid use. While rituximab, azathioprine, and mycophenolate mofetil are also used in the management of inflammatory myopathies, they are generally considered later options after IVIG has been