Abstract
BACKGROUND: The effect of coronavirus disease 2019 on the immune system is increasingly recognized. When severe, it causes immune dysregulation that may favor other infections, including Herpesviridae. Cytomegalovirus shares many innate immune pathways with severe acute respiratory syndrome coronavirus 2, which may potentiate each other. We describe a case of cytomegalovirus pneumonitis complicating the course of coronavirus disease 2019 in a patient with systemic lupus erythematosus/systemic sclerosis overlap and usual interstitial pneumonia, mimicking interstitial lung disease exacerbation. To the best of the authors' knowledge, this is the first case to be reported worldwide in the setting of connective tissue disease-associated interstitial lung disease. CASE DESCRIPTION: We describe the case of a 47-year-old white/Yemeni female who is known to have systemic lupus erythematosus/scleroderma overlap and usual interstitial pneumonia who was initially admitted with severe coronavirus disease 2019 pneumonia mandating intensive care. After initial improvement, it was later complicated with cytomegalovirus pneumonitis, mimicking interstitial lung disease exacerbation. The case was successfully treated with ganciclovir. CONCLUSION: Intriguingly, severe acute respiratory syndrome coronavirus 2 and cytomegalovirus may potentiate each other, since they share some innate immune pathways. Subjects with severe coronavirus disease 2019 and underlying connective tissue diseases and those who are immunosuppressed carry higher risk compared with other cohorts, which may mandate active surveillance for cytomegalovirus coinfection or reactivation. Among various immunosuppressive therapies that has been tried for cytokine storm, use of anti-interleukin-6 inhibitors in the aforementioned population may carry more harm than previously thought, which may suggest that is reasonable to omit its use in treating this group with coronavirus disease 2019. This case underlines an underrecognized and underreported cause of morbidity and mortality during the course of severe coronavirus disease 2019 and will help to alert clinicians of its occurrence.