Rhino-Orbito-Paranasal and Cavernous Sinus Mucormycosis Presenting with Extensive Cranial Nerve Palsies in a Patient with Diabetes Mellitus: A Case Report

Rhino-orbito-paranasal and cavernous sinus mucormycosis is a rapidly progressive angioinvasive fungal infection caused by moulds of the order Mucorales. It occurs predominantly in patients with poorly controlled diabetes mellitus and carries high mortality when diagnosis is delayed, particularly in South and South-East Asia. Here, the authors report a case of 56-year-old male with long-standing poorly controlled type 2 diabetes mellitus (Glycated Haemoglobin (HbA1c) 13.6%) and a prior episode of myocardial infarction presented with one month of progressive left nasal obstruction. Over the next two months, he developed complete left visual loss, total external ophthalmoplegia, proptosis, ptosis, trigeminal sensory loss involving branches V1-V3, and ipsilateral lower motor neuron facial nerve palsy. Histopathology of nasal crusting showed broad pauci-septate hyphae consistent with Mucorales, and fungal culture grew Rhizopus species. Magnetic Resonance Imaging (MRI) orbit demonstrated involvement of the left frontal, ethmoidal, sphenoid, and maxillary sinuses, with extension into the superomedial extraconal orbital space, orbital apex, and left cavernous sinus. Associated oedema of the extraocular muscles and pterygoid muscles, diffuse thickening of the left optic nerve, and mild proptosis were also noted. The patient was treated with left functional endoscopic sinus surgery, medial orbital decompression, and liposomal amphotericin B 250 mg daily for 21 days. The present case represents an unusually extensive pattern of cranial nerve involvement in Rhino-Orbito-Cerebral Mucormycosis (ROCM), affecting cranial nerves II-VII, and highlights the need for early tissue diagnosis, prompt antifungal therapy, and multidisciplinary management.