EN4.15 | Eustachian Tube Disorders — Summary & Reflection

KEY TAKEAWAYS

The Eustachian tube is a 35–37 mm fibrocartilaginous channel in adults comprising a bony medial third (always patent) and a cartilaginous lateral two-thirds (normally closed at rest, opened by tensor veli palatini during swallowing). In children, the tube is shorter (17–18 mm), more horizontal, and floppier, predisposing to ASOM and OME. The three ET functions — ventilation, drainage, and protection — explain why ET dysfunction underlies the entire otitis media spectrum. Two clinically important ET disorders exist with opposite pathophysiology: obstructive ET dysfunction (tube fails to open → negative pressure → OME/ASOM/CSOM) and patulous ET (tube fails to close → autophony, synchronous breathing sounds, positional relief in dependent head-down position). Obstructive dysfunction presents with ear fullness, fluctuating hearing loss, and recurrent otitis media; tympanometry shows Type C (negative pressure) or Type B (effusion). Patulous ET presents with autophony and respiratory synchronous TM movement on otoscopy; tympanometry is Type A. In adults with unilateral ET dysfunction, flexible nasendoscopy is mandatory to exclude nasopharyngeal carcinoma. Management of obstructive ET dysfunction: autoinflation, intranasal corticosteroids, adenoidectomy, grommets, and ET balloon dilation in refractory cases. Management of patulous ET: saline drops, nutritional restoration, and specialist bulking agents in severe cases. Grommet insertion for patulous ET is contraindicated — it worsens autophony.

REFLECT

A 9-year-old boy has had four episodes of ASOM in the past 12 months, with residual bilateral OME confirmed on tympanometry between episodes. His mother reports he has also had nasal obstruction, mouth breathing, and snoring at night for the past 2 years. Nasoendoscopy shows grade 3 adenoid hypertrophy obstructing the ET orifice bilaterally. PTA shows bilateral mild conductive hearing loss of 30 dB. Reflect on the following: What is the underlying ET pathology and its anatomical cause in this child? What is the surgical management and why are you doing TWO procedures rather than one? What will you tell the mother about the long-term prognosis — is this curative or will he need further intervention? And how does the child's expected growth trajectory affect your prediction for long-term ET function?