8-04: Diseases of the Eustachian Tube

1. EUSTACHIAN TUBE DYSFUNCTION

The tube that connects the middle ear to the nasopharynx—the eustachian tube—provides ventilation and drainage for the middle ear. It is normally closed, opening only during swallowing or yawning. When eustachian tube function is compromised, air trapped within the middle ear becomes absorbed and negative pressure results. The most common causes of eustachian tube dysfunction are diseases associated with edema of the tubal lining, such as viral upper respiratory tract infections and seasonal allergies. The patient usually reports a sense of fullness in the ear and mild to moderate impairment of hearing. When the tube is only partially blocked, swallowing or yawning may elicit a popping or crackling sound. Examination may reveal retraction of the tympanic membrane and decreased mobility on pneumatic otoscopy. Following a viral illness, this disorder is usually transient, lasting days to weeks. Treatment with systemic and intranasal decongestants (eg, pseudoephedrine, 60 mg orally every 4–6 hours; oxymetazoline, 0.05% spray every 8–12 hours), combined with autoinsufflation by forced exhalation against closed nostrils, may hasten relief. Autoinsufflation should not be recommended to patients with active intranasal infection, since this maneuver may precipitate middle ear infection. Allergic patients may also benefit from intranasal corticosteroids (eg, beclomethasone dipropionate, two sprays in each nostril twice daily for 2–6 weeks). Air travel, rapid altitudinal change, and underwater diving should be avoided until resolution. Eustachian tube dysfunction that does not resolve spontaneously or with medications may be treated with placement of the tympanostomy tube. Balloon dilation of the eustachian tube is a newer treatment being used in some centers in both adult and pediatric patients.

An overly patent eustachian tube (“patulous eustachian tube”) is a relatively uncommon, though quite distressing problem. Typical complaints include fullness in the ear and autophony (an exaggerated ability to hear oneself breathe and speak). A patulous eustachian tube may develop during rapid weight loss, such as following pregnancy, or it may be idiopathic. In contrast to eustachian tube dysfunction, the aural pressure is often made worse by exertion and may diminish during an upper respiratory tract infection. Although physical examination is usually normal, respiratory excursions of the tympanic membrane may occasionally be detected during vigorous breathing. Treatment includes avoidance of decongestant products and rarely surgery on the eustachian tube itself.