Orbital Apex Syndrome Due to Mucormycosis – Missed on Initial MRI

Abstract

A 64-year-old man with a history of diabetes mellitus and end stage renal disease presented with a several day history of cognitive decline, reduced right eye visual acuity accompanied with a complete right ophthalmoplegia in keeping with orbital apex syndrome. Initial MRI was unremarkable other than mucosal thickening in the frontal sinuses. He continued to clinically decline and repeat MRI revealed an edematous right optic nerve and a lack of enhancement within the sinuses was suspicion for invasive fungal infection. Given his history of diabetes, he was started on anti-fungal treatment and taken for debridement but passed away several days later. This case illustrates the importance of the orbital apex syndrome as a localization. Mucormycosis should be considered in acute onset ophthalmoplegia particularly in patients with diabetes and diabetic ketoacidosis. Empiric anti-fungal therapy should be started early for suspected rhino-orbital cerebral mucormycosis, although mortality remains high despite treatment.

Successful treatment of rhino-cerebral mucormycosis with dual antifungal therapy and minimal surgical debridement

“…In regards to imaging, CT scans are useful for showing extent of disease, abscess, bony destruction, pulmonary disease, and mucosal thickening [1] , [6] , [12] , [17] , [20] , [22] , [24] , [26] , [37] ; while MRI is used for evaluation of intracranial, intradural, and soft tissue inflammation [1] , [6] , [16] , [20] , [23] , [24] , [28] . Radiographic findings typically occur after clinical progression, so imaging may be nondiagnostic as seen in our case; thus, histology is the gold standard for diagnosis [6] , [8] , [18] , [34] .…”

“…Important aspects of mucormycosis pathophysiology involve elevated levels of serum iron and impaired host immunity [25] . Globally, the most common risk factor for mucormycosis infection is diabetes mellitus, especially states of uncontrolled diabetes and diabetic ketoacidosis, which is present in about 75% of cases [9] , [11] , [12] , [13] , [14] , [15] , [17] , [19] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] . Acidotic states promote the unbinding of iron from proteins leading to increased levels of serum iron which promotes fungal growth [25] .…”

“…Confusion and altered mental status are often associated with cerebral involvement and indicate a later stage of disease, often indicating intracranial spread [3] , [6] , [19] , [28] , [31] . Necrotic tissue is also present in more advanced disease [2] , [3] , [16] , [19] , [30] , [33] , [34] , [35] , [37] . Additionally, aneurysms, hemorrhage, dissection, and strokes can occur, as the fungus damages blood vessels and invades the arterial lamina [6] , [19] , [22] , [30] , [34] , [35] , [37] .…”

“…Necrotic tissue is also present in more advanced disease [2] , [3] , [16] , [19] , [30] , [33] , [34] , [35] , [37] . Additionally, aneurysms, hemorrhage, dissection, and strokes can occur, as the fungus damages blood vessels and invades the arterial lamina [6] , [19] , [22] , [30] , [34] , [35] , [37] .…”