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An 8-year-old boy accompanied by his mother presented with hearing loss. The patient failed a school-administered hearing screening as well as a subsequent hearing screening performed by his pediatrician. According to his mother, the patient had struggled with his hearing, often failing to respond to vocalizations and requiring statements to be frequently repeated. He reportedly passed his newborn hearing screening and his mother had no serious hearing concerns prior to his failed school screening. Physical examination revealed no effusions, while formal audiological testing revealed restricted middle ear mobility and bilateral moderately severe mixed hearing loss rising to normal hearing sensitivity in both ears (Figure, A). Medical history included corrective lens replacement surgery in early childhood and a family history of childhood hearing loss in the patient’s maternal grandfather. A noncontrast computed tomography (CT) scan of the temporal bones revealed bilateral enlargement of the vestibular aqueducts (Figure, B), fistulous communication between the internal auditory canal (IAC) and the basal turn of the cochlea (Figure, C), and a bulbous dilation of the IAC (Figure, D). Given the family history of childhood-onset hearing loss, genetic testing was performed and revealed genetic mutation of the POU3F4 gene.
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B. X-linked deafness 2
X-linked deafness 2, is a rare, nonsyndromic genetic deafness with characteristic radiological findings. In patients with this type of deafness, the vestibular aqueducts are enlarged, and many have a fistulous connection between the IAC and the basal turn of the cochlea.1 These anatomical changes are best demonstrated with CT imaging of the temporal bones.
Also known as stapes gusher syndrome and Nance deafness, X-linked deafness 2 was first described in 1973 by Nance et al as “X-linked mixed deafness with congenital fixation of the stapedial footplate and perilymphatic gusher.”2 Stapes gusher refers to the dramatic leakage of perilymphatic fluid during stapes surgery. While the occurrence of a gusher is a rare phenomenon, it is a devastating surgical complication if affected patients are not identified preoperatively via radiologic imaging.3 The association of X-linked deafness with stapes gusher is attributed to an aberrant communication between the subarachnoid and perilymphatic spaces. In the present case, the noncontrast CT images showed a fistulous communication between the IAC and the basal turn of the cochlea (Figure, B and C). This channel between the IAC and the basilar cochlea likely results from the absence of the lamina cribrosa, which is a bony plate that separates the 2 spaces.4 In a case series, Phelps et al5 demonstrated the described radiological findings in 16 of 24 male patients with X-linked mixed hearing loss. Likewise, Papadaki et al6 described the occurrence of X-linked deafness with stapes gusher in 2 sisters with mixed hearing loss. High-resolution CT scan of the 2 patients demonstrated bulbous dilation of the IAC as well as incomplete separation between the IAC and the basal turn of the cochlea.6
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Corresponding Author: Lauren Buck, MD, Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, 2500 N State St, Jackson, MS 39216 (firstname.lastname@example.org).
Published Online: July 18, 2019. doi:10.1001/jamaoto.2019.1701
Conflict of Interest Disclosures: No disclosures were reported.
Additional Contributions: We thank the patient’s parents and the patient for granting permission to publish this information.
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