RESULTS
Three GPA and one EGPA were included in this study (Table 1). Case 1 and
Case 2had recurrenceof acute SNHL with external otitis of the posterior
canal wall during an attempted taper of prednisolone (Fig. S1). Case 3
and Case 4 presented with persistent otitis media with aseptic discharge
and gradual progressive SNHL as an initial symptom (Fig. S1). Bilateral
ears were affected at the initial onset in Case 4. Vertigo with a
complete canal paresis was seen only in Case 3.Simultaneous facial
paresis was absent in all patients.
The signal intensity of each segment of the facial nerve was assessed in
five affected ears (Table 2). The geniculate ganglion was normally
enhanced with a moderate to intense signal intensity withoutan obvious
difference between affected and unaffected ears (Fig. 1A). In all
affected ears, the temporal and mastoid segments were significantly
enhanced(Fig. 1B, 1C, 1D, 2A, 2B). The enhancement was detected along
the course of the Fallopian canal on MIP images,and closely associated
with inflammation inthe promontory, mastoid, and eustachian tube (Fig.
2C, 2D). After immunosuppressive therapy,the enhancement was attenuated
to a level similar to that of unaffected ears (Fig. 1E), with a mean
signal intensity score of the mastoid segment from 2.7 at onset to 1.4
inremission. On the other hand, the cisternal, canalicular, and
labyrinthine segments were faintly enhanced and hardly detectable(Fig.
1A). Pachymeningitis or other intracranial involvements were not found.