Sudden-Onset Unilateral Blindness Due to Posterior Ethmoid Mucocele

Mucoceles of the paranasal sinuses are cyst-like masses that may occur due to impairment of normal mucociliary drainage. They are typically slow growing expansile lesions that can cause intraorbital and intracranial complications through bony erosion.¹ This case report describes acute symptoms from a sinus mucocele after an unrelated surgery on a previously asymptomatic patient.

A 39-year-old South-Asian male with a history of unspecified previous sinus surgery presented with sudden-onset right-sided vision loss upon awakening from an appendectomy 6 days prior. He described central vision darkness, blurriness in the periphery, right-sided temporal headaches, and dull right eye pain. On physical exam, his visual acuity was OD counting fingers at 1 foot and OS 20/20. Pupils were equal and reactive to light bilaterally without relative afferent pupillary defect. Neither proptosis nor ophthalmoplegia was observed. A CT scan of the head showed complete opacification of the right posterior ethmoidal air cells and sphenoid sinus. MRI of the orbits showed a 2.4 × 1.8 cm expanded fluid-filled posterior ethmoid cell consistent with a mucocele in an Onodi cell with possible dehiscence of the right optic nerve. The patient underwent endoscopic sinus surgery with marsupialization of the right posterior ethmoid mucocele which yielded thick purulent drainage. A dehiscent right optic nerve was identified intra-operatively. Postoperatively, the patient was started on Prednisone and Bactrim. Mucocele cultures yielded growth of Staph. aureus. Ophthalmology evaluation on postoperative day (POD) 1 demonstrated improved visual acuity to OD 20/50 in peripheral vision and resolution of right-sided headache. One month later, ophthalmology exam demonstrated improvement to OU 20/20.

Mucoceles of the posterior ethmoid and sphenoid sinuses occur less frequently than mucoceles of the frontal and frontoethmoidal sinuses.² Onodi cell mucoceles, which are even rarer, show a predilection for Asians, with one literature review showing that, 12 of 16 cases were of Asian descent.³ While origination in frontal, frontoethmoidal, or maxillary sinuses present with exophthalmos and ophthalmoplegia, posterior ethmoid and sphenoid sinus mucoceles can cause visual disturbance.⁴ The reported patient’s mucocele likely originated due to impaired sinus drainage in the setting of previous sinus surgery.⁵

Prior reports describe two mechanisms for vision loss secondary to sinus mucoceles: mucocele-induced bone resorption causing direct optic nerve compression ischemia or mucocele infection leading to inflammation of the optic nerve.⁶ An explanation of the acute symptom onset following an unrelated surgery is less clear. Interestingly, literature shows that 12 of 16 Onodi cell mucoceles present suddenly.³ We hypothesize that perioperative hemodynamics may have led to ischemic optic neuropathy of an already compressed optic nerve, or that Staph. aureus infection of the mucocele caused local inflammation. Our patient partially recovered vision on POD 1, which is prognostic of long-term treatment response to ESS.⁷ Surgical treatment is the most powerful option, with some degree of visual recovery in 76% of patients, regardless of acuity.^3,7 To conclude, although mucoceles are classically thought to be slow growing, a high index of suspicion must be maintained of their role in sudden onset vision loss as ESS can help mitigate permanent blindness.

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Artikel online veröffentlicht:
05. Februar 2024