Chronic Dysfunction of the Eustachian Tube

Health-care providers working in primary care, allergy, pediatrics, and otolaryngology frequently encounter both acute and chronic Eustachian-tube dysfunction (ETD).

This common condition can be challenging to treat, particularly in patients with a lifelong history of ETD. A properly functioning eustachian tube allows gas diffusion which equalizes middle-ear pressure with that of the environment. An improperly functioning eustachian tube can result in negative middle-ear pressure. Left untreated, this condition may lead to complaints of hearing loss, tinnitus, otalgia, vertigo (and subsequent tympanic membrane atelectasis), fulminate cholesteatoma formation, and otitis media.

The eustachian tube

Ear DiagramThe narrow Eustachian tube is part of the contiguous system that includes the nose, palate, and nasopharynx. The nasopharynx is proximal to the eustachian tube, and the middle ear and mastoid are located at its distal end. Directed downward, forward, and medially from the middle ear, the Eustachian tube opens approximately 1.25 cm behind and just below the posterior end of the inferior turbinate. The Eustachian tube of an adult sits at a 45° angle, while the angle is approximately 10° in infants. Additionally, an infant’s eustachian tube measures approximately 18 mm in length; the tube grows rapidly during childhood, reaching its adult length of 3-4 cm by age 7 years. The lumen of the tube will also increase with physical maturity.

Eustachian-tube function

The Eustachian tube drains or clears middle-ear secretions into the nasopharynx, protects the middle ear from nasopharyngeal pressure changes and secretions, and ventilates the middle ear so that the pressure within is equal to atmospheric pressure. Drainage of normal secretions from the middle ear to the nasopharynx via the eustachian tube is aided by mucociliary transport and repeated active tubal opening and closing.2 The four muscles associated with the eustachian tube (tensor veli palatini, levator veli palatini, salpingopharyngeus, and tensor tympani) are all are either directly or indirectly related to tubal function.

Normally closed at rest, the Eustachian tube opens when we yawn, sneeze, swallow, or chew, allowing air to enter the middle ear and mucus to flow out. This also promotes proper tympanic membrane function by enabling the equalization of middle-ear and atmospheric pressures. With normal function, middle-ear pressure is maintained between +50 mm and -50 mm H2O. The Ostmann fat pad, located in the inferolateral aspect of the eustachian tube, is thought to play a role in closing the tube to prevent backflow of nasopharyngeal secretions and likely contributes to protection of the tube.
Eustachian-tube dysfunction

ETD occurs when the tube fails to open properly or becomes blocked, thereby preventing the normal flow of air into the middle ear. This results in higher air pressure outside the tympanic membrane than in the middle ear, a condition that may cause long-term pathologic changes to the tube. Eustachian-tube pathology is strongly related to mucosal disease and associated hypertrophy, which can be precipitated by reactive disease (e.g., allergy) as well as other causes.

Such anatomic abnormalities as cleft palate and other craniofacial abnormalities may lead to inflammation of the Eustachian tube. Damage to the tube lining also can be directly related to viral infection, which is thought to result in decreased mucociliary clearance. Gastroesophageal reflux is thought to play a role in the development of middle-ear and eustachian-tube inflammation and may play a role in ETD as well. Nasopharyngeal pH has been noted to be lower in some patients with otalgia and adenoiditis.

Symptoms of ear tube dysfunction

Eustachian tube dysfunction
When atmospheric pressure rises or falls without change in the middle ear, the tympanic membrane cannot vibrate normally. This can result in temporary hearing problems and ear discomfort. Typical presenting complaints include aural fullness, hearing loss, tinnitus, dysequilibrium, intermittent sharp pain, a sensation of fluid in the ear, sustained pain (if blockage results in an ear infection), and difficulty popping the ears.6 Symptoms, which can last from a few hours to several months, typically are intermittent and can be temporarily relieved by swallowing, yawning, or chewing.

Causes of dysfunction

In many children, eustachian-tube ventilation is less efficient because of anatomic variances, making these patients susceptible to such middle-ear conditions as otitis media and otitis media with effusion. In addition, multiple upper respiratory infections (URIs) and enlarged adenoids and tonsils can further contribute to the increased incidence of middle-ear diseases in children. ETD may follow URI or exacerbations of allergic rhinitis. The nasal blockage and/or thickened mucus that develops during URI can cause significant inflammation of the eustachian tube. With growth, the Eustachian-tube function of children usually improves, as demonstrated by the reduced frequency of otitis media from infancy through maturity.

Habitual sniffing creates negative pressure within the middle ear. Air travel or scuba diving can cause ear pain secondary to negative middle-ear pressure as well. These activities may “lock” the ETD, leading to stasis of secretions and effusion secondary to barotraumas. For most patients, normal swallowing and chewing gum can equalize the pressure by helping air to travel up the eustachian tube.

An abnormally open tube is described as “patulous.” Patients with this condition will complain of echo when speaking (autophony) as well as ear fullness. They may also note that they can hear themselves breathe. Rapid weight loss may result in reduction in size of the Ostmann fat pad, decreasing its effect on closing and protecting the eustachian tube and middle ear and leading to symptoms of ETD.

Physical findings

While otoscopic findings of ETD are usually normal, examination in chronic ETD may demonstrate retraction pockets of the tympanic membrane. Rhinoscopy may reveal a deviated septum with or without inferior turbinate hypertrophy. Peritubal inflammation or mass may appear on nasopharyngoscopy. In acute otitis media, the tympanic membrane may be erythematous and bulging, while in chronic otitis media, the membrane may appear dull. In both instances, the membrane will demonstrate a sluggish response to pneumatic otoscopy.

Treatment

ETD is frequently mild and lasts only a few days. This is typically the case with the common cold, and no particular treatment is necessary. As previously noted, simple acts of swallowing, chewing, or yawning can be effective at alleviating symptoms. Inflation of the eustachian tube via the Valsalva maneuver can further break the negative pressure.

If symptoms do not go away within a few days, other treatment may be necessary. Decongestants (oral or nasal), steroids (oral or nasal), antihistamines, or leukotriene antagonists can be used to relieve congestion and enable the eustachian tube to open. To improve compliance, tell the patient that these medications can take time to build to their full effect.

ETD is usually treated with a combination of time, auto-insufflation, and medications. As stated, decongestants are helpful for acute symptoms but not chronic ETD. Be mindful of the cardiovascular effects of oral decongestants. Further consideration should be given to the early tachyphylaxis observed with the use of nasal decongestants as well.5 No provider wants to be responsible for the development of comorbid rhinitis medicamentosa. Always limit the use of nasal decongestants to three days.

In patients with uncontrolled laryngopharyngeal reflux, use of a proton-pump inhibitor is often helpful. Instruct patients with ETD to use a topical or oral decongestant 30 minutes before flying or diving (i.e., snorkeling or scuba).

Conclusion

If symptoms persist or if the cause of the ETD is unclear, referral to an otolaryngologist may be necessary. He or she can perform tympanometry to further assess eustachian-tube function. Tympanography, which measures middle-ear pressure, tympanic membrane movement, ear-canal volume, and acoustic reflexes, may detect the presence of effusions. Other tests include an audiogram and telescopic examination of the nose. Posterior rhinoscopic examination with a mirror or fiberoptic endoscopy helps visualize any mass obstructing the pharyngeal end of the eustachian tube. CT or MRI may be obtained to assess for temporal bone tumors.