Fulminant bilateral blindness despite initially normal neuroimaging in rhinocerebral mucormycosis

Rhinocerebral mucormycosis is a rapidly progressive and frequently fatal invasive fungal infection that most commonly occurs in patients with uncontrolled diabetes mellitus in the setting of diabetic ketoacidosis.

We present a woman in her 70 s with diabetic ketoacidosis, who developed right-sided facial numbness and ptosis, followed by acute, complete bilateral vision loss within hours. Initial cranial CT and diffusion MRI were unremarkable despite rapidly evolving cranial neuropathies. This created significant diagnostic uncertainty and prompted consideration of alternative diagnoses, including giant cell arteritis. Nevertheless, markedly elevated inflammatory markers and rapidly worsening ophthalmoplegia prompted further investigation. Orbital MRI and paranasal sinus CT revealed postseptal orbital involvement and extensive pansinusitis. Nasal endoscopy revealed black, necrotic crusts, and two aspiration cultures confirmed Mucor species. Liposomal amphotericin B was started without delay; however, the disease had already extended into the orbit and frontal brain parenchyma, making surgical debridement impossible. The patient died despite aggressive antifungal therapy.

Rhinocerebral mucormycosis should be suspected immediately in diabetic ketoacidosis patients who develop acute cranial neuropathies or sudden vision loss, even when initial neuroimaging is unrevealing. Clinical deterioration may precede radiological abnormalities in fulminant rhinocerebral mucormycosis, and delayed recognition may rapidly eliminate the possibility of surgical intervention.