The 14-Year-Old with Unilateral Hearing Loss and a Normal Exam
A 14-year-old presents with a 3-month history of left-sided hearing loss and occasional tinnitus. Otoscopy is normal; tuning fork testing lateralizes to the right with air conduction greater than bone conduction on the right. Audiometry shows a left moderate-to-severe sensorineural loss at 2-8 kHz with 100% word recognition on the right and 88% on the left. MRI of the internal auditory canal is ordered. The family asks whether imaging is necessary since the exam is normal.
1. Justify the MRI and describe what you are looking for.
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Justification: unilateral sensorineural hearing loss in a teenager is not benign by default. The differential includes acoustic neuroma/vestibular schwannoma, congenital malformation, and inner-ear anomalies. MRI with contrast of the internal auditory canals is the study of choice; it detects small tumors and characterizes the cochlea and vestibular aqueduct.
What to look for:
- Mass in the cerebellopontine angle or internal auditory canal (schwannoma, meningioma, epidermoid).
- Enlarged vestibular aqueduct (a common cause of pediatric SNHL).
- Cochlear or labyrinthine malformation.
- Signs of demyelination or stroke if sudden.
Judgment point: the exam tests that a normal otoscopic exam does not exclude retrocochlear pathology.
2. MRI shows an enlarged vestibular aqueduct on the left. How does this change management, and what counseling do you give about noise and head trauma?
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Management: enlarged vestibular aqueduct (EVA) is a radiologic marker, not a disease. It is associated with progressive or fluctuating SNHL and sometimes vestibular symptoms. Management is supportive:
- Baseline and serial audiometry.
- Hearing aids or FM systems as needed.
- Vestibular evaluation if symptoms.
- Consider genetics referral (SLC26A4/Pendred syndrome) and thyroid evaluation if Pendred is suspected.
Counseling:
- Avoid head trauma (contact sports with collision risk, trampolines) because of the association with sudden hearing loss and vestibular symptoms.
- Avoid loud noise and ototoxic medications.
- Report sudden hearing drops promptly; steroids may be considered.
Judgment point: the exam tests that you recognize EVA as a lifelong surveillance issue and counsel on modifiable risks.