Interstitial lung disease in polymyositis and dermatomyositis

Area of Science:

• Rheumatology
• Pulmonology
• Immunology

Background:

• Interstitial lung disease (ILD) complicates polymyositis and dermatomyositis (PM/DM) in approximately one-third of patients.
• ILD in PM/DM can manifest early, sometimes preceding muscle or skin symptoms, and significantly impacts patient survival.
• Nonspecific interstitial pneumonia is the most frequent histopathological pattern observed in PM/DM-associated ILD.

Purpose of the Study:

• To review the clinical course, histopathology, and treatment of interstitial lung disease in polymyositis and dermatomyositis.
• To differentiate between progressive and nonprogressive PM/DM-related lung disease for appropriate management.
• To evaluate the efficacy of various immunosuppressive therapies for PM/DM-associated ILD.

Main Methods:

• Literature review of studies on PM/DM and interstitial lung disease.
• Analysis of clinical presentation, histopathological findings, and treatment outcomes.
• Comparison of different immunosuppressive agents, including corticosteroids and cyclophosphamide.

Main Results:

• Nonspecific interstitial pneumonia, a more benign pattern than usual interstitial pneumonia, is common in PM/DM-related ILD.
• The clinical course of PM/DM-associated ILD is variable, necessitating careful monitoring.
• Corticosteroid monotherapy has shown limited efficacy, whereas cyclophosphamide, often combined with corticosteroids, demonstrates significant benefit.

Conclusions:

• Early recognition and monitoring of ILD in PM/DM are crucial for patient outcomes.
• Distinguishing progressive from nonprogressive disease guides the need for immunosuppressive therapy.
• Cyclophosphamide is a recommended first-line immunosuppressant for managing PM/DM-associated interstitial lung disease, particularly in progressive cases.