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

Abstract

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.

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

“…There have been several reported cases of mucormycosis in COVID-19 patients, and risk factors for mucormycosis in COVID-19 patients include diabetes or steroid-induced hyperglycemia, high iron and ferritin levels, steroid-induced immunosuppression, and prolonged hospitalization [3,18,19]. Infection usually occurs through inhalation of the spores, which invade the nasal mucosa and sinuses, causing rhinosinusitis [11].…”

“…Affected individuals at the early stages can present with fever, acute sinusitis, nasal congestion, purulent nasal discharge, and headache [14]. If not diagnosed and treated early, mucormycosis easily spreads to the brain by either direct extension through the cribriform plate, infratemporal fossa, inferior orbital fissure, and walls of the sinuses or the invasion of the arteries and veins with resultant vascular thrombosis and infarction [11,14,20,21]. The symptoms of intracranial infection include diplopia, ophthalmoplegia, acute vision loss, cranial nerve deficits, focal neurological deficits, and altered sensorium [11].…”

“…If not diagnosed and treated early, mucormycosis easily spreads to the brain by either direct extension through the cribriform plate, infratemporal fossa, inferior orbital fissure, and walls of the sinuses or the invasion of the arteries and veins with resultant vascular thrombosis and infarction [11,14,20,21]. The symptoms of intracranial infection include diplopia, ophthalmoplegia, acute vision loss, cranial nerve deficits, focal neurological deficits, and altered sensorium [11]. Sudden onset vision loss in rhino-orbito-cerebral mucormycosis has been associated with central retinal artery occlusion, ophthalmic artery necrosis, optic nerve infarction, or direct optic nerve infection [7].…”

“…There are even fewer cases of rhino-orbito-cerebral mucormycosis associated with optic nerve ischemia and ischemic neuropathy in the literature [9,10]. With the outbreak of coronavirus disease 2019 (COVID- 19), there have been reported cases of acute invasive rhino-orbito-cerebral mucormycosis in the setting of COVID-19 [11][12][13]. Additionally, multiple instances of mucormycosis in COVID-19 patients with poor glycemic control have been reported, with one multicentric study demonstrating mucormycosis in 1.8% of COVID-19 patients [14].…”

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

“…Ancillary findings of a dilated and thrombosed superior ophthalmic vein and luminal attenuation of the ipsilateral internal carotid artery (ICA) with or without thrombosis and vasculitis may be seen. Paracavernous soft tissue may also be seen [19,20,21] (Fig. 6c, 6d, 7 and 8).…”