The outcome of pulmonary function tests and high-resolution computed tomography of chest in post-coronavirus disease 2019-confirmed cases after 3 months of recovery

Background Coronavirus disease (COVID-19) is a recently prevalent infectious disease that is caused by a virus from the coronavirus family and causes acute respiratory syndrome. It is a pandemic catastrophe that has affected more than 60 million people around the world and has caused about 1.5 million deaths, as reported by the WHO. This disease affects the respiratory system and leads to different forms of symptoms and signs. Pneumonia is a common cause for hospitalization, with most patients treated in hospital wards and others requiring ICU. Although the number of complete recoveries from COVID-19 has increased, there is still concern about complications associated with the disease that appear after recovery. The studies that have looked at past types and other forms of coronavirus epidemics, such as SARS have shown that some cases had respiratory complications from the infection after being full recovered, as 36 and 30% of the entire study population had clinical and high-resolution computed tomography (HRCT) changes at 3 and 6 months after recovery, respectively. Mostly, the abnormalities seen in pulmonary function test (PFT) results are sequelae of diffusion capacity defect. In recovered cases of Middle East respiratory syndrome, 36% of patients showed HRCT sequelae at follow-up of 6 weeks, because of fibrosis. Data on COVID-19 indicate that prolonged disease and persistent symptoms show post-PFT affection and follow-up radiographic changes after recovery from COVID-19 as interstitial pulmonary changes and a degree of pulmonary vasculopathy. In recovered cases of COVID-19, capacity of diffusion is the commonest defect in lung function, followed by the restrictive pattern defects on spirometry; both are related to the degree of severity of pneumonic COVID-19. PFTs (involving spirometry as well as diffusion capacity) are considered as routine follow-up examinations for some of the recovered cases, especially severe cases. Rehabilitation programs of the respiratory system are an option strategy that might be considered. This study aims to show changes in pulmonary function and HRCT of chest in post-COVID-19-infected patients to detect long-term effects on the lungs after 3 months as obstructive or restrictive, or both, lung diseases. Patients and methods The study was conducted on 100 confirmed PCR-positive COVID-19 cases that were admitted to Ain Shams University Isolation Hospitals, and the follow-up was performed in the outpatient clinic. PCR samples