Post Covid Interstitial Lung Disease: Evolving Concepts

Post-COVID interstitial lung disease (PC-ILD) has been recognized as a notable manifestation of post-acute sequelae of SARS-CoV-2 infection. While most patients have fully recovered from COVID-19, some patients have remained with persistent respiratory symptoms, along with interstitial changes on imaging studies and compromised pulmonary function.1-3 These observations suggest that COVID-19 infection may cause persistent lung injury beyond the acute illness. PC-ILD is a heterogeneous group of conditions4,5, with a spectrum that includes predominantly inflammatory and potentially reversible lesions, as well as established fibrotic changes in the lung parenchyma.3 Unlike idiopathic pulmonary fibrosis, the course of PC-ILD is variable, and most patients have shown partial or complete radiographic and functional recovery over time. The pathogenesis is postulated to include persistent epithelial injury, immune dysregulation, endothelial injury, and aberrant repair responses triggered by the acute infection.6-8 At present, diagnosis is based on clinical evaluation, high-resolution computed tomography, and pulmonary function tests, but there are no standardized criteria for diagnosis and treatment.9,10 Corticosteroids could be beneficial for selected patients with an inflammatory pattern, but the use of antifibrotic therapy is still investigational.11-13 Long-term follow-up and prospective studies are necessary to understand the course of the disease and improve management practices for affected patients.7