The Worst May Be Yet to Come - Post-Viral Pulmonary Fibrosis in a COVID-19 Patient with Mild Symptoms

Introduction: COVID-19 has a variable clinical presentation ranging from flu-like symptoms to respiratory failure. Most patients have a mild form of disease and often recover at home over a period of weeks. For some, the highest morbidity of COVID-19 may not be associated with the acute phase of the disease, but rather the longstanding post-viral pulmonary fibrosis. Case Description: A 49-year-old man with a past medical history of coronary artery disease, obstructive sleep apnea, hypertension, and type two diabetes mellitus presented to the emergency department with a four-day history of fever, nausea, and diarrhea. He denied cough or dyspnea. Chest radiograph revealed bibasilar ground glass opacifications. He was positive for severe acute respiratory syndrome coronavirus 2 by polymerase chain reaction testing. His oxygen saturation was 95% on room air and he was discharged home without treatment. Over the following days, he developed a dry cough and mild dyspnea, but he did not desaturate on room air. He was prescribed a short course of steroids by his outpatient pulmonologist. He gradually improved over the course of two weeks and he was never hospitalized. Computed tomography (CT) of the chest 10 weeks after diagnosis revealed bilateral patchy ground glass opacities in all lobes and interstitial components with architectural distortion in the lower lobes (Image 1). A pulmonary function test performed 12 weeks after diagnosis showed an FVC 83%, FEV1 85%, TLC 75%, RV 37%, and DCLO 88%. The patient continued to experience mild dyspnea with exertion 2 months after the resolution of the infection. Conclusion: Pulmonary fibrosis is not a post-viral phenomenon limited to severe cases of COVID-19 and can occur following mild presentations managed at home. Thus far, risk factors for the development of pulmonary fibrosis secondary to COVID-19 have been reported to be advanced age, disease severity, length of intensive care unit stay, smoking, and alcoholism. Our case report calls for a re-evaluation of these risk factors. While pharmaceutical treatments are typically only administered to hospitalized patients, there may be basis for treating mild cases with the intent of preventing post-viral pulmonary fibrosis. Further, outpatient clinicians may consider monitoring for changes in pulmonary architecture with pulmonary function tests or high-resolution CT scans in all recovered COVID-19 patients regardless of symptom severity.