Importance of Eliciting History of Prior SARS-CoV-2 Infection in Evaluation of New Diagnosis of Interstitial Lung Disease

Introduction: About 30% of patients with severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) had persisting lung abnormalities after acute illness. However, little is known whether SARS coronavirus 2 (SARS-CoV-2) infection will cause long-term pulmonary complications. We present our experience with a patient with a new diagnosis of interstitial lung disease (ILD) during the pandemic. Case: A 61-year-old man with history of hypertension and obstructive sleep apnea developed acute onset cough and dyspnea in March 2020. The patient was not initially tested for COVID-19 because of the local department of public health's stay-at-home advisory. Cough resolved but dyspnea persisted. Two months later, polymerase chain reaction for SARS-CoV-2 was checked and was negative. Due to ongoing dyspnea, a CT chest was performed 5 months after symptom onset and showed diffuse, mild sub-pleural reticulonodular opacities in upper and lower lungs, concerning for ILD (Figure 1). Pulmonary function testing (PFT) showed normal spirometry and lung volumes, and mild impairment in gas exchange. Work up for causes of ILD, including assessment for exposures and serologies for rheumatologic disease, was unremarkable. IgG antibody for SARS-CoV-2 was detected (25.9 AU/ml;normal<1.00 AU/ml);IgM was undetectable. Work up for other causes of dyspnea included an echocardiogram, CT pulmonary angiogram, and ventilation-perfusion scan that revealed no evidence of structural heart disease or thromboembolic disease. Discussion: Given no other etiology of ILD was identified, it is most plausible that our patient had acute COVID-19 infection in March and developed secondary ILD over the ensuing months. Previous studies of patients with SARS and MERS have found occurrences of pulmonary fibrosis and PFT abnormalities persisting many months after onset of infection. Thus, it is prudent to be vigilant for symptoms of lung disease in patients with a known history of COVID-19 infection. An additional diagnostic challenge, as with the case above, lies with patients who present with new onset ILD but without a confirmation of COVID-19, particularly given the limited access to testing in the early stages of the pandemic. In these patients, we suggest a thorough history that includes screening for symptoms suggestive of prior viral syndromes, particularly with associated anosmia or dysgeusia, that can point to a history of COVID-19 infection. Another option is consideration of serologic testing, although such tests must be interpreted with caution in view of the paucity of supporting evidence and the possibility of both false-positives and false-negatives.