Post-COVID pulmonary fungal infections: An unanticipated predicament or a ticking time bomb? Clinico-microbiological profile of cases encountered during the second wave of COVID-19 pandemic at a teaching hospital in the Himalayas with a brief literature review

Abstract

Introduction: This study attempts to generate preliminary data regarding post-COVID pulmonary fungal infections, namely, COVID-19-associated pulmonary aspergillosis (CAPA), COVID-19-associated pulmonary mucormycosis (CAPM), and mixed infections from the Himalayas and compares the micro-radio-clinical profile and outcomes of the affected patients.

Materials and methods: A retrospective data analysis was conducted, where clinical profiles, microbiological and radiological reports, and outcomes of n = 16 patients of post-COVID pulmonary infections were compared.

Results: Of n = 16 patients, n = 7 had CAPA (n = 5 Aspergillus fumigatus, n = 1 Aspergillus flavus, and n = 1 Aspergillus niger), n = 5 CAPM (Rhizopus arrhizus), and n = 4 with mixed infections (n = 3 infected with Aspergillus fumigatus and Rhizopus spp. and n = 1 with Aspergillus flavus and Rhizopus arrhizus). Thick-walled cavitary lesions, air-fluid levels, and multiple centrilobular nodules were some of the common radiological findings reported among these patients.

Conclusion: The immuno-compromised state following COVID-19 infection and treatment might be responsible for the progression of regular exposure to the dense Himalayan vegetation into an invasive pulmonary fungal infection. Suspecting post-COVID pulmonary fungal infection is necessary for primary care physicians to ensure timely referral to higher centers. Mixed pulmonary fungal infections (coinfection with Aspergillus spp. and Rhizopus spp.) are also emerging as important sequelae of COVID-19.

Keywords: COVID-19; COVID-19-associated pulmonary aspergillosis (CAPA); COVID-19-associated pulmonary mucormycosis (CAPM); mixed pulmonary fungal infection.

Figure 1

KOH Mount of lower respiratory tract sample of a patient showing hyaline broad aseptate and pauciseptate hyphae suggestive of Rhizopus spp

Figure 2

Gram-stained smear of a lower respiratory tract sample of a patient showing acute angle branching suggestive of Aspergillus spp

Figure 3

KOH Mount of a lower respiratory tract sample of a patient showing hyaline aseptate hyphae (blue arrow) and thin hyaline septate hyphae (red arrow) suggestive of mixed infection caused by Rhizopus spp. and Aspergillus spp., respectively

Figure 4

Axial lung and mediastinal window and coronal lung window scans of the chest (a-c) showing a thin-walled cavity with internal contents along with surrounding ground-glass attenuation along the wall of the cavity. Axial lung window scans (d) displaying extensive COVID-related changes in the form of consolidation admixed with fibrotic changes. The presence of a cavity with internal contents and surrounding ground-glass attenuation is highly suggestive of invasive fungal infection

Figure 5

Axial lung window of chest displaying well-defined thin-walled cavity in the superior segment of left lower lobe (arrow in a) with internal debris-like contents (star in a). COVID-related changes are seen as retracting bands of fibrosis admixed with areas of consolidation (arrow in b). The presence of a cavity with internal contents is highly suggestive of superadded fungal infection