Patulous Eustachian Tube

Frequency

Incidence of patulous eustachian tube is 0.3-6.6%, and 10-20% of persons who have it are bothered enough by symptoms to seek medical attention. This condition is more common in females than in males and is usually present in adolescents and adults; it is rarely found in young children.

See the image below.

Anatomy of the ear.

In most instances, patulous eustachian tube is idiopathic. Weight loss (sometimes caused by chronic illness) and pregnancy are identified as important predisposing factors. Neurologic disorders that may cause muscle atrophy (eg, stroke, multiple sclerosis, motor neuron disease) have been implicated. Adhesion formation in the nasopharynx following adenoidectomy or radiotherapy may also predispose individuals to a patulous tube. The condition is sometimes associated with medications (eg, oral contraceptives, diuretics). Other predisposing factors include fatigue, stress, anxiety, exercise, and temporomandibular joint syndrome.

On the other hand, in a study using computed tomography (CT) scanning to compare the bony portion of the eustachian tube of patients with patulous eustachian tube with that of controls, Ikeda et al found the shape to be almost identical, indicating that this part of the structure exercises no pathologic influence on patulous eustachian tube.[3]

Under normal resting conditions, the eustachian tube is closed and only opens with swallowing or autoinflation. In unaffected individuals, closure of the eustachian tube is maintained by luminal and extraluminal factors, which include intrinsic elasticity of the tube, surface tension of moist luminal surface, and extraluminal tissue pressure. Muscle tone of tensor veli palatini dilates the lumen; damage to tensor veli palatini following cleft palate surgery may produce a patulous tube. Weight loss can also lead to abnormal patency caused by reduced tissue pressure and loss of fat deposits in the eustachian tube region. Pregnancy alters opening pressures of the eustachian tube because of the change in surface tension; estrogens acting on prostaglandin E affect surfactant production. Scarring in the postnasal space following adenoidectomy may result in traction of the tube in a patent position.

History

Major symptoms of patulous eustachian tube include fluctuating aural fullness, roaring tinnitus synchronous with nasal respiration, audible respiratory sounds, distorted autophony (ie, the abnormal perception of one's own breath and voice sounds) with echoing occasionally severe enough to interfere with speech production, and sensation of plugged ear. Autophony is the most frequent symptom associated with patulous tube.[4]

Vertigo and hearing loss can also occur because patulous eustachian tube allows excessive pressure changes to occur in the middle ear; these pressure changes are then transmitted to the inner ear through ossicular movement. Some patients may have difficulty eating because the noise of chewing is transmitted to the ear. Patulous eustachian tube is often misdiagnosed because symptoms mimic those of middle ear effusion. Symptoms may relate to cyclical changes occurring in the mucosa of the eustachian tube. Some patients find relief from the associated increased mucosal congestion by lying down, by putting the head between the knees, or during upper respiratory tract infection.

Compression of the jugular veins produces peritubular venous congestion and may relieve symptoms. Patients sometimes sniff repetitively to close the eustachian tube, and this may lead to long-term negative middle ear pressure. Decongestants or a ventilation tube in the drum can worsen symptoms.

Diagnosis can often be made based on history alone.

Physical examination

Examination findings are usually unremarkable; canals and eardrums appear normal. The eardrum can be atrophic secondary to the constant drum motion from breathing or sniffling. Synchronous movement of the tympanic membrane with respiration is exaggerated with forced respiration or with the patient breathing in and out through the nose with one nostril occluded; the tympanic membrane moves medially on inspiration and laterally on expiration. With the patient sitting upright, small movements of pars flaccida occur, which disappear when the patient is supine. Examine the ear with an operating microscope to detect subtle movements.

Surgery is indicated if the patient continues to have significant otologic symptoms despite medical therapy.

Surgical therapy for a patulous eustachian tube is contraindicated in patients who are pregnant or have mild symptoms. These patients need informative reassurance alone (see Medical Therapy).

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• CT scanning in an axial plane has been used to show the presence of a patulous eustachian tube.

• CT scanning may be useful in making the diagnosis in some patients.

• Radiology only assists in the diagnosis of anatomic patency.

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• Tympanometry may detect movements of the tympanic membrane with nasal respiration, especially with the patient in an erect position.[2]

• Distorted sounds of nasal respiration and speech may be heard with a microphone placed in the external meatus.

• With sonotubometry, a test sound is introduced into the nasal vestibule and a microphone is fitted into the external auditory meatus. With a patulous tube, sound pressure level in the external canal is at a maximum; because the tube does not close, no sudden drop in transmitted sound occurs.

• Observe a regular change in middle ear pressure when increasing or decreasing the ambient pressure during the measurement of impedance in a pressure chamber. Usual variations in pressure with opening and closing of the tube are not seen because the tube remains open all of the time.

See the list below:

• In some patients with patulous tube, direct nasopharyngoscopy may show the continuous presence of a triangular opening of the eustachian tube orifice.

• Transnasal endoscopic (video analysis) exam has been used to study the nasopharyngeal opening of the eustachian tube during rest, swallowing, and yawning.

Patients with a patulous eustachian tube who are pregnant and those with mild symptoms (most patients) need informative reassurance alone. Patients who have symptoms during pregnancy are symptom-free after delivery.

Advise patients to do the following:

• Increase or regain lost weight

• Avoid diuretics

• Recline or lower head when symptoms occur

Topical administration (nasal preparation) with anticholinergics may be effective for some patients.

Estrogen (Premarin) nasal drops (25 mg in 30 mL normal saline, 3 gtt tid) or oral administration of saturated solution of potassium iodide (10 gtt in glass of fruit juice tid) has been used to induce swelling of the eustachian tube opening.

Nasal medication containing diluted hydrochloric acid, chlorobutanol, and benzyl alcohol has been demonstrated to be effective in some patients. This has been reported to be well tolerated with little or no adverse effects. Approval by the Food and Drug Administration (FDA) is pending.

The following methods may be used for treatment of a narrow lumen caused by inflammatory response or scar tissue:

• Bezold's remedy of insufflation of a solution of salicylic acid and boric acid (1:4 ratio) - Repeat treatments are always necessary

• Eustachian tube diathermy with sequential application of ureteric diathermy probe

• Cautery with 20% silver nitrate

Electrocoagulation has been discarded because of morbidity (ie, damage to middle cranial fossa dura, damage to mandibular nerve).

The following methods may be used for treatment of a narrow lumen caused by extrinsic compression:

• Paraffin injection

• Teflon injection anterior to the eustachian tube orifice - Serious complications may occur.

• Gelfoam injection - Results are good, but temporary; very little morbidity is associated. Autologous fat or cartilage graft plugging of the eustachian tube at its nasopharyngeal orifice, in conjunction with myringotomy and ventilation tube placement, has been successful in some patients.[5]

• Alter function of palatal muscles, with or without pterygoid hamulotomy - Stroud et al (1974) described transposition of tensor veli palatini tendon medial to pterygoid hamulus (transpalatal approach). Transection of tensor veli palatini is another option.

• Occlusion of the eustachian tube - Bluestone and Cantekin (1981) recommend occlusion of bony eustachian tube with an intravenous indwelling catheter via anterior tympanotomy. A catheter is filled with methyl methacrylate glue, and the tympanostomy tube is inserted to aerate the middle ear and prevent development of serous effusion. The catheter can be removed at any time. A modification of the Bluestone technique involves placement of the catheter through myringotomy.

• Myringotomy and insertion of a ventilating tube - This may provide temporary relief for some patients. These steps are relatively simple to perform and reversible and have minimal complications. Occasionally, myringotomy and insertion of a ventilating tube result in increasing the patient's discomfort.

• Surgical scar tissue removal in nasopharynx - This may benefit patients with adhesions from a prior operation.

Calcium hydroxyapatite injection represents another therapy for patulous eustachian tube, being used to manage incompetent tubal valves via mass effect.[6]

Oh et al described the successful treatment of patulous eustachian tube with autologous tragal cartilage, finely chopped and endoscopically injected submucosally into the anterior and posterior portions of the nasopharyngeal eustachian tube.[7]

Similarly, a study by Jeong et al indicated that insertion of a tragal cartilage chip into an intractably patulous eustachian tube to fill in the tubal valve concavity can significantly reduce autophony. At average 16.4-month follow-up, four of 14 ears (28.6%) experienced complete relief of autophony, with satisfactory improvement found in another five ears (35.7%). No complications, such as otitis media or occlusion symptoms, occurred in any of the treated ears.[8]

Rotenberg et al reported on the successful use of multilayer endoscopic ligation for the treatment of autophony in patulous eustachian tube. Transnasal endoscopy was used in 14 ears to guide treatment combining fat plugging, endoluminal cauterization, and suture ligation, with complete subjective resolution of autophony in nine ears (64.3%) and partial, but sustained and satisfactory, subjective improvement in three others (21.4%).[9]

In a study of 21 patients with patulous eustachian syndrome, Boedts reported that 76.2% obtained relief from autophony via paper patching of the tympanic membrane, with relief being permanent in a portion of these cases. Such patching may reduce autophony by adding greater stiffness to the tympanic membrane.[10]

Eustachian tube diathermy has been associated with complications such as intermittent secretory otitis media, trigeminal nerve damage, and middle cranial fossa dural burns.

Serous effusions have developed in patients treated by silver nitrate or Teflon injections. Teflon injections are also associated with serious complications, including cerebral thrombosis and death. These complications followed inadvertent injection of Teflon into the internal carotid artery, which occurred in the era before the common use of endoscopic placement. Gelfoam or Teflon injections can also result in total obstruction of the eustachian tube. Middle ear effusions can develop in patients undergoing tensor veli palatini transection and/or transposition with or without pterygoid hamulotomy.

A retrospective study by Ward et al indicated that patients with patulous eustachian tube dysfunction who undergo treatment with shim (catheter) insertion or obliteration of the eustachian tube lumen are more likely to have symptom resolution at 12 months than are those who are treated with calcium hydroxyapatite injection or eustachian tube reconstruction. However, the shim and obliteration treatments are also associated with a higher rate of otitis media with effusion.[11]

Patients with vestibular symptoms experience improvement of vertigo with treatment of patulous tube.

A study by Wu et al indicated that in patients with a history of weight loss who are treated for patulous Eustachian tube, those who had undergone a rapid weight loss are more likely to experience symptom improvement than are those who underwent a more gradual loss of weight. The odds ratio for symptom improvement for the study’s rapid–weight-loss group was 4.8.[12]

A literature review by Ikeda et al reported mean symptom improvement for the following patulous eustachian tube procedures[13] :

• Ventilation tube insertion - 58%
• Mass loading of the tympanic membrane - 50%
• Eustachian tube injection - 47%
• Plug surgery - 81%
• Shim surgery - 62%
• Tuboplasty - 41%
• Eustachian tube closure - 66%

A discussion of the merits of different treatments is restricted by insufficient numbers and by lack of adequate long-term follow-up data to allow valid conclusions to be drawn. Very little basic research has been performed to investigate mechanisms responsible for normal eustachian tube function. Until more basic research and properly conducted trials are performed, this situation is likely to remain.