Bilateral optic nerve infarction in rhino-cerebral mucormycosis: A rare magnetic resonance imaging finding

A case series of mucormycosis mimics on MRI—Tales of respite amidst the havoc

Background

Rhinocerebral mucormycosis is new bandit amidst present COVID-19 pandemic, it is an acute and lethal opportunistic fungal infection affecting immunocompromised and diabetic patients. Since the disease has got high morbidity and mortality despite aggressive treatment, radiologists play a very crucial role in early and accurate diagnosis. Erroneous diagnosis should be refrained by logistic approach and thorough clinico-radiological correlation.

Material and methods

Ours was a cross sectional study included six cases after taking written informed consent who recently presented with mucormycosis like symptoms and imaging findings during a period of 1 month, but by detailed clinical and radiological evaluation, we concluded that all these cases were either physiological mimics or extraneous artefacts, this helped greatly in relieving undue anxiety of patients and referral physicians and also avoided unnecessary further workup. This study was conducted after approval by the institutional ethical committee.

Results

Our study included 3 males and 3 females of age ranging from 32 to 62 years, all of which had history of COVID-positive having mild to moderate CT severity score who were treated with steroids and oxygen therapy (except one case). The most common presenting symptom was headache followed by nasal congestion. The mucor mimickers encountered were benign black turbinate sign, artifacts due to cosmetic dermal fillers and dental fillings, hemangioma, prolonged prone ventilation, and fungal ball.

Conclusions

Amidst the sudden spurt in the number of cases of mucormycosis in our country in the present COVID era, there has been an increase in the number of imaging requisitions. This series of cases aims to sensitize radiologists about the importance of detailed clinical history, thorough clinic-radiological correlation and at times also taking extra efforts to reconnect to patients regarding specific clinical history and avoid fallacious diagnosis.

Intracranial manifestations of rhinocerebral mucormycosis: a pictorial essay

Rhinocerebral mucormycosis has emerged as a common coinfection in coronavirus disease 2019 (COVID-19) patients during the convalescence period. Frequent spread of disease from sinonasal mucosa to bone, neck spaces, orbit, and brain occurs along the perivascular/perineural routes or through direct invasion. Brain involvement represents severe manifestation and is often associated with poor functional outcomes and high mortality rates. Magnetic resonance imaging (MRI) is the modality of choice for the intracranial assessment of disease severity in mucormycosis. Early and accurate identification of intracranial extension is imperative to improve survival rates. With this pictorial essay, we aim to familiarize the readers with the cross-sectional imaging features of intracranial complications of mucormycosis. The radiological details in this essay should serve as a broad checklist for radiologists and clinicians while dealing with this fulminant infection.

Multimodal Imaging in Rhinoorbitocerebral Mucormycosis Associated with Type 2 Diabetes After COVID-19

PURPOSE

This case series analyzed the appropriateness of computed tomography (CT) and magnetic resonance imaging (MRI) for visualization of rhinoorbitocerebral mucormycosis (ROCM) patterns associated with type 2 diabetes (T2D) post-recovery from coronavirus disease 2019 (COVID-19).

METHODS

The study included 24 patients with invasive ROCM after having recovered from COVID-19. All patients underwent CT examinations and microbiological and histological verification; 5 patients underwent MRI.

RESULTS

The CT and MRI patterns noted in our patients revealed involvement of skull orbits, paranasal sinuses, large arteries, and optic nerves, with intracranial spread and involvement of the cranial base bones. Using brain scan protocol for CT provided better soft-tissue resolution. We found that extending the MRI protocol by T2-sequence with fat suppression or STIR was better for periantral fat and muscle evaluations.

CONCLUSION

Computed tomography of the paranasal sinuses is the method of choice for suspected fungal infections, particularly mucormycosis. However, MRI is recommended if there is suspicion of orbital, vascular, or intracranial complications, including cavernous sinus extension. The combination of both CT and MRI enables determination of soft tissue invasion and bony destruction, thereby facilitating the choice of an optimal ROCM treatment strategy. Invasive fungal infections are extremely rare in Europe; most of the related data are provided from India and Middle Eastern or African nations. Hence, this study is notable in its use of only diagnosed ROCM cases in Russia.

SARS-CoV-19-associated Rhino-orbital and cerebral Mucormycosis: Clinical and Radiological Presentations

We describe presenting clinical and imaging manifestations of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-associated Rhino-oculo-cerebral mucormycosis (ROCM) in a hospital setting during the second wave of SARS-CoV-2 pandemic in India. Data on the presenting manifestations were collected from 1 March to 31 May 2021. Associations between clinical and imaging findings were explored, specifically: (1) the presence or absence of orbital pain and infiltration of a superior orbital fissure on imaging; (2) the presence of unilateral facial nerve palsy and pterygopalatine fossa infiltration and geniculate ganglion signal on contrast magnetic resonance imaging, and (3) vision loss and optic nerve findings on imaging. Orbital pain was reported by 6/36 subjects. A fixed, frozen eye with proptosis and congestion was documented in 26 (72%), complete vision loss in 23 (64%), and a unilateral lower motor neuron facial nerve palsy in 18 (50%). No association was found between the presence of orbital pain and superior orbital fissure infiltration on imaging. The ipsilateral geniculate ganglion was found to enhance more profoundly in 7/11 subjects with facial palsy and available magnetic resonance (MR) imaging, and the ipsilateral pterygopalatine fossa was found infiltrated in 14. Among 23 subjects with complete loss of vision, 9 (39%) demonstrated long-segment bright signal in the posterior optic nerve on diffusion MR images. We conclude that orbital pain might be absent in SARS-CoV-2-associated ROCM. Facial nerve palsy is more common than previously appreciated and ischemic lesions of the posterior portion of the optic nerve underlie complete vision loss.

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.

Rhino-orbito-cerebral Mucormycosis: Pictorial Review

Mucormycosis (MCR) is a fulminant, potentially lethal, opportunistic fungal infection. Diabetes, immunocompromised states and elevated serum iron levels are the most important risk factors for contracting MCR infection. Recently, MCR co-infections have been observed in patients with COVID-19 disease owing to a complex interplay of metabolic factors and corticosteroid therapy. Rhino-orbito-cerebral mucormycosis (ROCM) is the most common clinical form of MCR infection and refers to infection of the nasal cavities, paranasal sinuses, neck spaces, orbits and intracranial structures. Sinonasal inoculation is typically the primary site of infection; the necrotising and angioinvasive properties of the fungus facilitate its spread into adjacent structures. In this review, we discuss the pertinent mycology and risk factors of MCR infection. The review also aims to acquaint the reader with the cross-sectional imaging appearances of ROCM and its complications. All the cases discussed in this pictorial essay are microbiologically and/or histopathologically proven cases of ROCM with concomitant COVID-19 infection.

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

Rhino-orbito-cerebral mucormycosis (ROCM) has regained significance following its resurgence in the second wave of the COVID-19 pandemic in India. Rapid and progressive intracranial spread occurs either by direct extension across the neural foraminae, cribriform plate/ethmoid, walls of sinuses, or angioinvasion. Having known to have a high mortality rate, especially with intracranial extension of disease, it becomes imperative to familiarise oneself with its imaging features. MRI is the imaging modality of choice. This pictorial essay aims to depict and detail the various intracranial complications of mucormycosis and to serve as a broad checklist of structures and pathologies that must be looked for in a known or suspected case of ROCM.

Cerebral mucormycosis: neuroimaging findings and histopathological correlation

INTRODUCTION

Mucormycosis are infections caused by molds of the order Mucorales. These opportunistic infections are rare, difficult to diagnose, and have a poor prognosis. We aimed to describe common radiographic patterns that may help to diagnose cerebral mucormycosis and search for histopathological correlations with imaging data.

METHODS

We studied the radiological findings (CT and MRI) of 18 patients with cerebral mucormycosis and four patients' histopathological findings.

RESULTS

All patients were immunocompromised and/or diabetic. The type of lesions depended on the infection's dissemination pathway. Hematogenous dissemination lesions were most frequently abscesses (59 lesions), cortical, cortical-subcortical, or in the basal ganglia, with a halo aspect on DWI for lesions larger than 1.6 cm. Only seven lesions were enhanced after contrast injection, with different presentations depending on patients' immune status. Ischemia and hemorrhagic areas were also seen. Vascular lesions were represented by stenosis and thrombosis. Direct posterior extension lesions were bi-fronto basal hypodensities on CT and restricted diffusion without enhancement on MRI. A particular extension, perineural spread, was seen along the trigeminal nerve. Histopathological analysis found endovascular lesions with destruction of vessel walls by Mucorales, microbleeds around vessels, as well as acute and chronic inflammation.

CONCLUSIONS

MRI is the critical exam for cerebral mucormycosis. Weak ring enhancement and reduced halo diffusion suggest the diagnosis of fungal infections. Involvement of the frontal lobes should raise suspicion of mucormycosis (along with aspergillosis). The perineural spread can be considered a more specific extension pathway of mucormycosis.

Magnetic resonance imaging in rhino-orbital-cerebral mucormycosis

Coronavirus disease-associated mucormycosis (CAM) is an established clinical entity in India. In the past 4 months, there has been a sharp upsurge in the number of CAM cases in most parts of the country. Early diagnosis can be lifesaving. Magnetic resonance imaging (MRI) imaging remains the corner stone of management in patients with ROCM. This review discussed the utility of MRI imaging in ROCM with an emphasis on the ideal MRI protocol in a suspected case of ROCM, the pathways of spread of infection, the classic diagnostic features, MRI for staging of the disease, MRI for prognostication, MRI for follow up, and imaging features of common differentials in ROCM. The pit falls of MRI imaging and a comparison of CT and MRI imaging in ROCM are discussed. The clinical interpretation of areas of contrast uptake and those of necrosis and its relevance to treatment are discussed. This review aims to familiarize every member of the multidisciplinary team involved in managing these patients to be able to interpret the findings on MRI in ROCM.

A Unique Radiologic Case of Optic Nerve Infarction in a Patient With Mucormycosis

ABSTRACT

This is a rare presentation of a unilateral optic nerve infarction of the left eye caused by mucormycosis in a 51-year-old man with poorly controlled Type 2 diabetes. Diffusion-weighted MRI of the orbit demonstrated extensive infarction of the left optic nerve with ipsilateral cavernous sinus thrombosis and periorbital adnexal inflammation. Left orbital exenteration and sinus debridement were performed, and mucormycosis involving the optic nerve sheath was confirmed on histopathology.