Mucor in a Viral Land: A Tale of Two Pathogens

Abstract

Purpose: COVID-19 infection, its treatment, resultant immunosuppression, and pre-existing comorbidities have made patients vulnerable to secondary infections including mucormycosis. It is important to understand the presentation, temporal sequence, risk factors, and outcomes to undertake measures for prevention and treatment.

Methods: We conducted a retrospective, interventional study on six consecutive patients with COVID-19 who developed rhino-orbital mucormycosis and were managed at two tertiary ophthalmic referral centers in India between August 1 and December 15, 2020. Diagnosis of mucormycosis was based on clinical features, culture, and histopathology from sinus biopsy. Patients were treated with intravenous liposomal amphotericin B with addition of posaconazole and surgical debridement of necrotic tissue.

Results: All patients were male, mean age 60.5 ± 12 (46.2-73.9) years, type 2 diabetics with mean blood glucose level of 222.5 ± 144.4 (86-404) mg/dL. Except for one patient who was diagnosed with mucormycosis concurrently with COVID-19, all patients received systemic corticosteroids for the treatment of COVID-19. The mean duration between diagnosis of COVID-19 and development of symptoms of mucor was 15.6 ± 9.6 (3-42) days. All patients underwent endoscopic sinus debridement, whereas two patients required orbital exenteration. At the last follow-up, all six patients were alive, on antifungal therapy.

Conclusion: Mucormycosis is a life-threatening, opportunistic infection, and patients with moderate to severe COVID-19 are more susceptible to it. Uncontrolled diabetes mellitus and use of corticosteroids increase the risk of invasive fungal infection with mucormycosis which can develop during the course of the illness or as a sequelae. High index of suspicion, early diagnosis, and appropriate management can improve survival.

Keywords: COVID-19; Corticosteroids; diabetes mellitus; mucormycosis.

Figure 1

Clinical pictures of Case 3 showing orbital apex involvement with complete ptosis and ophthalmoplegia of the left eye. The eye is quiet with no perception of light

Figure 2

Axial scan of MRI orbit and brain of the same patient (Case 3) showing mild proptosis of the left eye, diffuse involvement of the ethmoid and sphenoid sinus, orbital apex (white arrow) and extension into the cavernous sinus

Figure 3

Clinical picture of Case 2 with (a) left periocular edema, complete ptosis and (b) proptosis, conjunctival congestion, and severe chemosis

Figure 4

Clinical picture of Case 4 after treatment with antifungals and surgical debridement with resolution of orbital inflammation and recovery of ocular movements of the right eye

Figure 5

T1 Axial section of MRI orbit with brain showing (a) invasive fungal infection involving the ethmoid sinus, orbital apex and ipsilateral cavernous sinus (white arrow). (b) Post treatment with antifungals and endoscopic sinus debridement showing minimal residual lesion (white arrow)

Figure 6

Guideline for diagnosis and treatment of mucormycosis in patients with COVID-19 (Modified from Song et al.[10]). Abbreviations: allo-HSCT = Allogenic hematopoietic stem cell transplant, GMS = Gomori's methenamine silver, HM = Hematopoietic malignancies, PAS = Periodic acid-Schiff stain, SOT = Solid organ transplant

Figure 7

Proposed guideline for surgical debridement and orbital exenteration for rhino-orbito-cerebral mucormycosis based on disease extent