Sudden Bilateral Sensorineural Hearing Loss in a Child with Enlarged Vestibular Aqueduct

Introduction: A vestibular aqueduct greater than 1.5 mm is considered enlarged and has been suspected as a cause of sudden sensorineural hearing loss in children. Such a hearing loss is most usually reported to be bilateral with a fluctuating course. Associated developmental abnormalities of the temporal bone are considered as etiologic factors, whereas diagnosis is confirmed by CT scan and MRI.

Case Presentation: A 6-year-old boy was presented to the emergency department complaining of sudden deafness after a fall to the ground 6 hours earlier. Both of the tympanic membranes were intact, tympanometry showed type A curves without acoustic reflex bilaterally, and pure tone audiometry revealed bilateral deafness. In his medical history artificial fertilization and maternal gestational diabetes mellitus were reported. The patient was admitted to the hospital and treated with the proper therapy for idiopathic sudden deafness, though with minimal hearing improvement across standard audiometric frequencies. A more detailed hearing evaluation revealed absence of transiently evoked otoacoustic emissions (TEOAEs), and ABR waveforms in 90 dB. Temporal bone CT scan was performed 3 days after admission and revealed bilaterally enlarged vestibular aqueducts. This finding was confirmed by an MRI 4 days later. The child's parents were informed of the situation and were given options for further management.

Conclusion: Enlarged vestibular aqueduct syndrome is considered the most frequent temporal bone abnormality revealed by CT scan studies. Modern imaging techniques have facilitated its diagnosis at an increasing rate. ENT specialists should take into account this syndrome during evaluation and management of sudden sensorineural hearing loss.