Clinical Features and Prognosis of Sudden Sensorineural Hearing Loss Secondary to Intralabyrinthine Hemorrhage

Background and Objectives: A number of etiologies of idiopathic sudden sensorineural hearing loss (ISSNHL) have been proposed, including viral infection, vascular disturbance, and immune-mediated mechanisms. Intralabyrinthine hemorrhage (ILH) as a cause of SSNHL is extremely rare, and there have been no studies defining the characteristics of hearing impairment and prognosis in patients with ISSNHL due to ILH. This study aimed to investigate the difference in impaired hearing patterns and prognosis for hearing recovery between patients with ISSNHL due to ILH confirmed by magnetic resonance imaging (MRI) and sex-and age-matched patients with ISSNHL due to causes other than ILH. Subjects and Methods: We compared the results of audiometry and MRI in 12 patients who had ILH on MRI (hemorrhage group) and in 23 sex-and age-matched controls without abnormal findings related to their hearing loss on MRI (non-hemorrhage group). Initial hearing impairment, progression, and recovery of hearing loss were compared between the two groups. Results: A majority of patients (92%) in the hemorrhage group complained of dizziness. Initial hearing impairment was more frequent in the hemorrhage group than in the non-hemorrhage group (94.09 +/- 35.9 vs. 66.66 +/- 30.1, p-value=0.036). The final recovery threshold in the hemorrhage group was worse (78.19 +/- 46.26 vs. 37.17 +/- 31.96, p-value=0.014) than that in the non-hemorrhage group. In the hemorrhage group, hearing recovery seemed to occur less often at high frequencies (2,000, 4,000, and 8,000 Hz) than at low frequencies (250, 500, and 1,000 Hz). Conclusions: The presence of ILH was associated with poor hearing prognosis and the occurrence of vertigo. The abrupt onset of hearing loss associated with vertigo and the presence of hyperresonance on fat-suppressed T1-weighted MRI images of labyrinthic fluid strongly suggests acute intralabyrinthine hemorrhage, and is predictive of considerable hearing impairment and poor prognosis.