Post COVID lung fibrosis (PCLF) or post COVID lung sequelae (PCLS): Which one is the right choice?

Abstract

Lung is the primary target organ in COVID-19 disease with diverse clinical and radiological presentations and outcome. It has caused minimal to moderate lung disease in some patients and in some cases caused deadly acute respiratory distress syndrome (ARDS). COVID-19 disease caused lung damage by direct virus induced alveolar damage, cytokine induced alveolar and vascular damage and microvascular thrombosis resulting into acute hypoxic respiratory failure. COVID-19 pneumonia evolved over period of three weeks in cases with ARDS as natural course of illness. Usually, ARDS resolves by fibrosis or resolution as final outcome. Similarly, in COVID-19 recovered cases of advanced disease or those suffering from ARDS are having post COVID lung disease. Lung fibrosis is final radiological outcome of COVID-19 pneumonia documented in proportionately majority of cases. Post COVID lung fibrosis is considered as worrisome radiological complication observed during early phase of pandemic. Time trends of final radiological outcome has evolved over months with or without treatment with antifibrotics and steroids. Importantly, Post COVID lung fibrosis resolved more than fifty percent cases in six months and nearly in all cases after one year. Post COVID lung fibrosis is considered as ‘health issue of great concern’ initially in post pandemic phase of first wave, and due to its resolving nature over time period; now considered as ‘sigh with relief’ due to its reversible pathophysiology. Post COVID sequel is minimal residual effects of COVID-19 lung disease irrespective of disease severity in past. We recommend to use term post COVID sequel over post COVID lung fibrosis.