Diffuse Interstitial Lung Disease Fundamentals

📋 Course Outline

1. Definition and pulmonary interstitium
2. Pathogenesis of interstitial infiltrates
3. Classification of diffuse interstitial lung disease
4. Diagnostic workup for PID
5. Major etiologies of chronic PID
6. Clinical course and complications
7. Treatment principles
8. Idiopathic pulmonary fibrosis and sarcoidosis

📖 1. Definition and pulmonary interstitium

🔑 Key Concepts & Definitions

• Diffuse infiltrative interstitial pneumopathies : Diffuse infiltrative interstitial pneumopathies are a heterogeneous group defined by diffuse interstitial infiltration visible on imaging.
• Pulmonary interstitium : Pulmonary interstitium is the supporting connective tissue of bronchovascular axes, inter- and intralobular septa, and the tissue under pleura with interalveolar septa.
• Interstitial infiltration pattern : Interstitial infiltration can be cellular or fibrous, and fibrosis is described as irreversible in these diseases.
• Diffuse interstitial opacities : Diffuse interstitial opacities are the shared radiologic presentation across these pneumopathies.

📝 Essential Points

• Interstitial involvement can include the interstitium only, or alveolar space involvement that may dominate the presentation in some entities.
• Histopathology includes interstitial cellular or fibrous infiltrate, with fibrosis stated as irreversible.
• Pulmonary interstitium infiltration leads to impaired gas diffusion and impaired elastic system function.