COVID-19 Associated Rhino-orbito-cerebral Mucormycosis: Clinical Profile and Imaging Spectrum

Abstract

Introduction: Rhino-orbito-cerebral mucormycosis is a fatal disease caused by saprophytic fungi seen almost exclusively in diabetic and immunocompromised patients. Aim: To describe various imaging findings of mucormycosis, and to emphasise the importance of imaging in its diagnosis and management. Materials and Methods: A retrospective, observational, single centre study was done including patients with clinical and microbiological evidence of rhino-orbito-cerebral mucormycosis, who had a history of Coronavirus Disease 2019 (COVID-19) infection and had undergone Computed Tomography (CT) and/ or Magnetic Resonance Imaging (MRI) scan of the head, orbit, and paranasal sinuses during the period of one month from 1st-31st May 2021. The clinical and imaging data of 67 such cases were interpreted and analysed by two radiologists. Results: The study included 67 patients out of which 44 were male and 23 were female, and the average age of patients was 49±13 years. During their treatment for COVID-19, 55 (82.08%) patients had a history of hospitalisation and administration of supplemental oxygen, all 67 (100%) patients had taken broad spectrum antibiotics, 56 (83.58%) patients had taken steroids, 20 (29.85%) patients previously had a history of diabetes with worsening of glycaemic control during COVID-19 infection, and 47 (70.15%) patients were diagnosed with new onset hyperglycaemia. On imaging i.e., on CT and/or MRI with or without contrast, the infection was found to primarily affect the sino-nasal region. There was unilateral or bilateral involvement of single or multiple paranasal sinuses in all 67 patients with involvement of nasal cavity in 42 patients. Maxillary sinus was the most common and consistently involved sinus seen in all 67 patients, followed by ethmoid sinus seen in 54 patients. Additionally, 56 patients had extra-sinus disease with spread along vessels, nerves, or via bone erosion. CT showed soft tissue thickening, oedema, and fat stranding with or without bone erosion as the predominant finding in involved areas, while MRI showed Short Tau Inversion Recovery (STIR) hyperintense soft tissue thickening and postcontrast enhancement as the main finding. Conclusion: There is a complex interplay of various COVID-19 infection and treatment related factors that are responsible for increased susceptibility to mucormycosis infection. Imaging plays an important role in aiding the diagnosis, determining the extent and spread of infection, guiding the extent of the surgical intervention, and determining the prognosis of these patients. The contrast enhanced MRI along with plain CT should be the preferred choice of imaging.

Keywords

• coronavirus disease-2019
• invasive fungal infection
• rhizopus
• sinonasal disease