Acute optic neuritis: Association with paranasal sinus inflammatory changes on magnetic resonance imaging

The authors compared the frequency of paranasal sinus inflammatory changes (SIC) on brain magnetic resonance imaging (MRI) obtained from 23 patients w ith new onset acute optic neuritis (ON) and 48 control patients who underwe nt outpatient MRI of the brain for reasons other than ON. The authors found a higher frequency of paranasal SIC in patients with ON (83%) than in cont rols (54%) (p = 0.02). The distribution of paranasal SIC (in ON and in cont rols )was maxillary (83% and 52%), ethmoid (4% and 2%), frontal (9% and 14% ), and sphenoid (4% and 10%). Frequency of the maxillary SIC was significan tly higher (p = 0.02) in patients with ON than in controls. Further evaluat ion of maxillary paranasal SIC with a grading system showed the presence of thickened mucosal lining of the sinuses (grade I) in 17% (ON) and 23% (con trols), mucous retention cysts within the sinuses (grade II) in 48% (ON) an d 25% (controls), and severe mucosal thickening with complete or near-compl ete filling of the sinus or an air-fluid level within the sinus (grade III) in 17% (ON) and 4% (controls). Combined frequency of grade II and grade II I SIC was significantly higher in the ON group than in controls (p = 0.005) , as was the frequency of grade III SIC alone (p = 0.02). Grade I SIC did n ot significantly differ between the groups. There was a trend (p = 0.09) to ward a higher prevalence of bilateral sinus inflammatory changes in patient s with bilateral ON. These findings suggest that ON may be associated with sinus inflammatory changes.