Neuro-ophthalmological presentation of pneumosinus dilatans

Abstract

Pneumosinus dilatans (PSD) is a rare disease characterized by an abnormal expansion of an air-filled paranasal sinus. Because of the pressure effect on the adjacent structures, PSD may present with several neurological signs, the ocular ones being the most common. In the present study, we describe a case of frontal PSD with diplopia, proptosis, ophthalmoplegia, and compressive optic neuropathy. Imaging showed a large amount of air in the right orbit continuous with the ipsilateral frontal sinus. Endoscopic sinus surgery was performed to eliminate a valve-like mechanism created by an increased pneumatization of the Agger nasi cell above the ostium frontalis. Surgery was effective in restoring the normal communication between the sinus and the nasal cavity, thus resulting in full recovery of severe visual impairment. The distinction between PSD, pneumocele, and hypersinus is an important one since these disorders share some clinical features, but require different treatments. PSD visual prognosis is mainly related to its associated syndromes and their surgical treatment. If PSD occurs as an idiopathic disorder with simple sinus expansion, visual prognosis is good when appropriate surgery is performed. At present, endoscopic sinus surgery is preferable to the external approach for treatment of PSD.