Interstitial Lung Disease Diagnosis and Management

Introduction to ILD

The American Thoracic Society and European Respiratory Society recommend a multidisciplinary approach for ILD diagnosis, which improves diagnostic accuracy and patient outcomes 4
CTD-associated ILD represents 20% of all ILD cases, with SSc-ILD and RA-ILD accounting for 31% and 39% of CTD-ILDs respectively 1
ILD pathogenesis involves inflammation and/or progressive fibrosis of lung parenchyma, with a proportion developing progressive pulmonary fibrosis (PPF) causing irreversible damage and increased mortality 2

The American College of Rheumatology suggests that dyspnea on exertion is the primary symptom of ILD, though symptom assessment alone lacks sensitivity—90% of HRCT-confirmed ILD patients may not report dyspnea or cough 3
Fatigue is a common but nonspecific symptom that may be masked by other organ involvement or comorbidities (myopathy, cardiac disease) 2
Fine inspiratory crackles ("velcro" crackles) on lung auscultation have moderate sensitivity for early ILD identification 3
High-resolution CT (HRCT) is the gold standard for diagnosing ILD subtypes, with 91% sensitivity and 71% specificity 6

The European Respiratory Society recommends a step-wise approach for ILD diagnosis, including comprehensive history, physical examination, laboratory testing, imaging, and functional assessment 4
Disease-specific biomarkers, such as anti-topoisomerase (Scl-70) and rheumatoid factor (RF), predict disease activity and indicate the need for additional testing 4
Pulmonary function testing provides crucial prognostic information, with a 5% FVC decline over 12 months associated with approximately 2-fold increased mortality 3
The 6-minute walk test with oxygen saturation monitoring detects exercise-induced desaturation indicating gas exchange impairment 3

Treatment decisions must integrate the underlying etiology, disease severity, and balance between inflammatory versus fibrotic processes through multidisciplinary consensus 5, 3
For CTD-associated ILD, first-line treatment includes immunosuppressive agents (mycophenolate mofetil, rituximab, tocilizumab) regardless of fibrosis pattern 5
Antifibrotic therapy (nintedanib or pirfenidone) slows annual FVC decline by 44-57% in patients with progressive pulmonary fibrosis 3
Supportive care, including structured exercise therapy, oxygen therapy, and inhaled treprostinil, improves symptoms and quality of life in patients with ILD 3