Spectrum of intracranial complications of rhino-orbito-cerebral mucormycosis - resurgence in the era of COVID-19 pandemic: a pictorial essay

A Retrospective Study of Imaging of Invasive Rhino-Orbital-Cerebral Mucormycosis in the COVID-19 Pandemic in a Tertiary Care Center

Aim The study aims to analyze the imaging findings of invasive rhino-orbital-cerebral mucormycosis (ROCM) in patients who had COVID-19. Materials and methods This retrospective descriptive study was done on confirmed (culture and histopathology) patients who had a COVID-19 infection. The data was collected from the record section from May 2021 to June 2021. Imaging data were analyzed, and findings were tabulated according to statistical methods. Results Radiological evaluation, including CT and MRI, was done in 48 cases. The ethmoid sinus was the most common sinus involved in 60.41% of cases, followed by the maxillary sinus (52.09%). Unilateral pansinusitis was observed in 21 cases (43.75%). Among periantral extensions, retroantral fat involvement was the most common finding, seen in 24 cases (50%). Lamina papyracea and the walls of the maxillary sinus were involved in eight cases (16.67%). A total of 38 cases (79.17%) exhibited involvement of the extraconal compartment, while 32 cases (66.67%) showed involvement of the intraconal compartment. In intracranial involvement, infarct was noted in 13 cases (27%), and cavernous sinus involvement in nine cases (18.75%). Conclusions ROCM is a life-threatening fungal infection in immunocompromised patients, especially diabetics. Imaging of ROCM plays a pivotal role in early diagnosis, the extent of disease, surgical planning, prognosis, and the response to treatment. Radiologists must know the imaging features and patterns of extension of ROCM.

COVID-19-Associated Rhino-Orbito-Cerebral Mucormycosis: A Single Tertiary Care Center Experience of Imaging Findings With a Special Focus on Intracranial Manifestations and Pathways of Intracranial Spread

Background and objective The COVID-19 pandemic and mucormycosis epidemic in India made research on the radiological findings of COVID-19-associated mucormycosis imperative. This study aims to describe the imaging findings in COVID-19-associated mucormycosis, with a special focus on the intracranial manifestations.  Methodology Magnetic resonance imaging (MRI) scans of all patients with laboratory-proven mucormycosis and post-COVID-19 status, for two months, at an Indian Tertiary Care Referral Centre, were retrospectively reviewed, and descriptive statistical analysis was carried out. Results A total of 58 patients (47 men, 81%, and 11 women, 19%) were evaluated. Deranged blood glucose levels were observed in 47 (81%) cases. The intracranial invasion was detected in 31 (53.4%) patients. The most common finding in cases with intracranial invasion was pachymeningeal enhancement (28/31, 90.3%). This was followed by infarcts (17/31, 55%), cavernous sinus thrombosis (11/58, 18.9%), fungal abscesses (11/31, 35.4%), and intracranial hemorrhage (5/31, 16.1% cases). The perineural spread was observed in 21.6% (11/51) cases. Orbital findings included extraconal fat and muscle involvement, intraconal involvement, orbital apicitis, optic neuritis, panophthalmitis, and orbital abscess formation in decreasing order of frequency. Cohen's kappa coefficient of interrater reliability for optic nerve involvement and cavernous sinus thrombosis was 0.7. Cohen's coefficient for all other findings was 0.8-0.9. Conclusions COVID-19-associated rhino-orbito-cerebral mucormycosis has a plethora of orbital and intracranial manifestations. MRI, with its superior soft-tissue resolution and high interrater reliability, as elucidated in this study, is the imaging modality of choice for expediting the initial diagnosis, accurately mapping out disease extent, and promptly identifying and scrupulously managing its complications.

Management of Mucormycosis in Post COVID-19 Patients and Its Outcome in a Tertiary Care Center: Our Experience

To assess the common presentation and extent of disease involvement clinically and radiologically and treatment modalities, sequalae of the disease, complications and treatment response. Mucormycosis is a life-threatening infection that most commonly affects immunocompromised individuals and an exponential increase in the incidence of Rhino-orbital-cerebral mucormycosis was witnessed in the second wave of the COVID-19 pandemic, despite aggressive multimodal treatment carries a significant risk of mortality. A high index of suspicion is required in order to begin the appropriate diagnostic workup and treatment. This study is conducted to access the outcome and management of mucormycosis in post covid 19 patients. The prospective study includes 180 Patients, who are attending to E.N.T. outpatient department, Triage and patients referred from other departments who had suspected/confirmed Rhino-orbital-cerebral mucormycosis/underwent surgery and/or medical treatment or both. In our study mucormycosis predominantly affected age group between 40 and 60 years, more common in males (77.8%) than females (22.2%), 77.8% patients had post covid status. Most common risk factor was diabetes mellitus.76% patients had undergone endoscopic/open surgery and 24% patients underwent only medical treatment. Among 138 patients operated, 40% had recurrence and mortality was 16.1% (significantly reduced). Early diagnosis and prompt intervention is paramount to reduce morbidity and mortality. Liposomal Amphotericin B is most effective antifungal with manageable side effects. Patients who underwent Radical debridement either endoscopically or open approach, had better outcome with minimal recurrence rates. Combined medical and surgical treatment has better outcome, lesser recurrence and mortality.

Pathogenesis and Pathology of COVID-Associated Mucormycosis: What Is New and Why

Purpose of Review

There is global increase in the incidence of mucormycosis. However, a sudden increase in the COVID-associated mucormycosis (CAM) was noted, particularly in India, during the second wave of the COVID-19 pandemic. The interplay of factors involved in the pathogenesis is complex. In this review, the influence of pre-existing disease, exaggerated risk factors, altered milieu due to COVID-19 itself and the consequences of its treatment on the host pathogen interactions leading to the disease and morphology of the fungus will be highlighted.

Recent Findings

Hyperglycemia, acidosis, available free iron, lowered host defenses, and the fungal virulence factors promote the growth of Mucorales. There is a high background prevalence of diabetes mellitus (DM) in India. Uncontrolled or undiagnosed DM, COVID-19 itself, and inappropriate administration of corticosteroids in high doses and for prolonged periods result in hyperglycemia. Diabetic ketoacidosis (DKA) and metabolic acidosis due to hypoxia or renal failure contribute to acidic pH and dissociate bound iron from serum proteins. The host defenses are lowered due to COVID-19-induced immune dysregulation, hyperglycemia itself, and administration of corticosteroids and immune suppressants for the treatment of COVID-19. The altered metabolic milieu in the local microenvironment of nose and paranasal sinuses (PNS) promotes specific interaction of glucose-regulated protein-78 (GRP-78) on host cells with spore coat protein homologue (CotH 3) on Mucorales resulting in rhino-orbito-cerebral mucormycosis (ROCM) as the predominant clinical form in CAM. The pathology is extensive soft tissue involvement with angioinvasion and perineural invasion. Melanized hyphae and sporangia were seen on histopathology, which is unique to CAM. While many factors favor the growth of Mucorales in CAM, hyperglycemia, hyperferritinemia, and administration of hyperbaric oxygen result in reactive oxygen species (ROS) and inadequate humidification results in dehydration. Melanization is possibly the adaptive and protective mechanism of Mucorales to escape the unfavorable conditions due to the treatment of COVID-19.

Summary

High background prevalence of DM, inappropriate administration of corticosteroids and immune dysregulation due to COVID-19 favor the growth of Mucorales in CAM. Melanization of Mucorales hyphae and sporangia on histopathology probably represent adaptive and protective mechanism due to the treatment with hyperbaric oxygen with inadequate humidification as well as the metabolic alterations.

MR imaging spectrum in COVID associated Rhino-Orbito-Cerebral mucormycosis with special emphasis on intracranial disease and impact on patient prognosis

In the wake of the ongoing Coronavirus Disease 2019 (COVID-19) pandemic, a new epidemic of COVID associated mucormycosis (CAM) emerged in India. Early diagnosis and prompt treatment of this deadly disease are of paramount importance in improving patient survival. MRI is the cornerstone of diagnosis of early extrasinus disease, particularly intracranial complications which have traditionally been associated with a high mortality rate. In this review, we depict the sinonasal, perisinus, orbital and intracranial involvement in CAM. Special emphasis is laid on intracranial disease which is categorized into vascular, parenchymal, meningeal, bony involvement and perineural spread. Vascular complications are the most common form of intracranial involvement. Some unusual yet interesting imaging findings such as nerve abscesses involving the optic, trigeminal and mandibular nerves and long segment vasculitis of the internal carotid artery extending till its cervical segment are also illustrated. In our experience, patient outcome in CAM (survival rate of 88.5%) was better compared to the pre-pandemic era. Presence of intracranial disease also did not affect prognosis as poorly as traditionally expected (survival rate of 82.8%). Involvement of brain parenchyma was the only subset of intracranial involvement that was associated with higher mortality (p value 0.016). The aim of this review is to familiarise the reader with the MR imaging spectrum of CAM with special focus on intracranial complications and a brief account of their impact on patient prognosis in our experience.

COVID-19-Related Rhino-Orbito-Cerebral Mucormycosis Complicated by the Optic Nerve and Optic Tract Ischemia With Ischemic Neuropathy

Mucormycosis is a life-threatening invasive fungal infection usually seen in immunocompromised patients and patients with poorly controlled diabetes mellitus with or without diabetic ketoacidosis. We present a rhino-orbito-cerebral mucormycosis (ROCM) case in a coronavirus disease 2019 (COVID-19) patient complicated by the optic nerve and optic tract ischemia with ischemic neuropathy. Both CT and MRI played an essential role in diagnosing ROCM and the accompanying complications in our patient.

CT showed sinonasal sinusitis and MRI showed the sinusitis and its progression to ROCM. MRI also showed necrosis involving the bilateral orbits, basal ganglia, thalamus, internal capsule, hypothalamus, optic chiasm, optic nerves, olfactory bulbs, and skull base. ROCM associated with optic nerve ischemia is a rare but life-threatening complication of COVID-19, especially in patients with underlying diabetes and/or those treated with corticosteroids. Physicians should be aware of this complication as early diagnosis may improve the chances of survival in such patients.