Morphological and functional sequelae after COVID-19 pneumonia

Background Following coronavirus disease 2019 (COVID-19), a proportion of patients report prolonged or worsening symptoms and impairments. These symptoms are increasingly referred to as "long COVID" syndrome. They may be associated with radiological changes on computed tomography (CT) and pulmonary function impairment. Objectives To discuss the role of long-term assessment of COVID-19 patients to determine which patients may benefit from follow-up. Materials and methods This article presents the current results of clinical, radiological, and pulmonary function follow-up tests after COVID-19 pneumonia. Results Chronic fatigue and dyspnea are the most common persistent symptoms after COVID-19. Patients also present impaired exercise capacity. On CT, ground-glass opacities and parenchymal bands are the most common residual changes after COVID-19 pneumonia, histologically corresponding to organizing pneumonia. A proportion of patients who had severe COVID-19 pneumonia may show fibrotic-like changes during follow-up. Patients with severe acute infection may present with a restrictive syndrome with lower diffusing capacity for carbon monoxide (DLCO) and total lung capacity (TLC) values. Overall, significant and continuous improvement in all symptoms as well as radiomorphological and functional changes were observed over time. Conclusions Patients with persistent symptoms after COVID-19 should be evaluated and treated in specialized post-COVID-19 clinics in a multidisciplinary manner.