Patulous Eustachian tube
Patulous Eustachian tube (PET) is the name of a physical disorder where the Eustachian tube, which is normally closed, instead stays intermittently open. When this occurs, the person experiences autophony, the hearing of self-generated sounds. These sounds, such as one's own breathing, voice, and heartbeat, vibrate directly onto the ear drum and can create a "bucket on the head" effect. PET is a form of eustachian tube dysfunction (ETD), which is said to be present in about 1 percent of the general population.[1]
| Patulous Eustachian tube | |
|---|---|
| Other names | Patent Eustachian tube |
| Specialty | ENT surgery |
Signs and symptoms
With patulous Eustachian tube, variations in upper airway pressure associated with respiration are transmitted to the middle ear through the Eustachian tube. This causes an unpleasant fullness feeling in the middle ear and alters the auditory perception. Complaints seem to include muffled hearing and autophony. In addition, patulous Eustachian tube generally feels dry with no clogged feeling or sinus pressure.
Some patients with this condition are disturbed by the perceived volume of their voice, causing them to speak very quietly. Their own voice may also sound lower to other people, because the trachea has more volume when the Eustachian tube is open. The patient may also sound as if they have congestion when speaking. Some sufferers may have difficulty in normal activities. They may also experience increased breathing rate, such as that brought on by physical activity. The increased activity not only increases the rate and force of pressure changes in the airway, which is therefore transmitted more forcefully into the middle ear, but also drives increased blood flow to peripheral muscles, compounding the problem by further depleting the Eustachian tube of extracellular fluid and increasing patency. The combination can lead to severe exacerbation of the symptoms. The urge to clear the ear is often mentioned.
Autophonia (self-hearing from inside, strongly amplified) seems to be a common symptom to all PET patients. Unfortunately, its presence also reveals an advanced degree of patency, requiring in most cases surgical management. Other symptoms of PET, such as tinnitus, fullness and ear blockage, can also be reported by patients suffering from obstructive ET dysfunction. This differential diagnosis problem unfortunately leads to some surgeries proposed by well-intentioned but inexperienced ENT surgeons. Some of these surgeries may make things worse.
At the beginning, patients hear their own voice or its echo from inside.[2][3] They describe it as being amplified and unpleasant. Patients frequently avoid speaking and retire in a rising solitude. Lying head down may help since it increases venous blood pressure and congestion of the mucosa.
Causes
Patulous Eustachian tube is a physical disorder. The exact causes may vary depending on the person. Weight loss is a commonly cited cause of the disorder due to the nature of the Eustachian tube itself and is associated with approximately one-third of reported cases.[4] Fatty tissues hold the tube closed most of the time in healthy individuals. When circumstances cause overall body fat to diminish, the tissue surrounding the Eustachian tube shrinks and this function is disrupted.[5]
Activities and substances which dehydrate the body have the same effect and are also possible causes of patulous Eustachian tube. Examples are stimulants (including caffeine) and exercise. Exercise may have a more short-term effect than caffeine or weight loss in this regard.
Pregnancy can also be a cause of patulous Eustachian tube due to the effects of pregnancy hormones on surface tension and mucus in the respiratory system.[6]
Granulomatosis with polyangiitis can also be a cause of this disorder. It is yet unknown why.
PET can occur as a result of liquid residue in the Eustachian tube, after suffering a middle ear infection (otitis media).
Diagnosis
Upon examination of a suspected case of patulous Eustachian tube, a doctor can directly view the tympanic membrane with a light and observe that it vibrates with every breath taken by the patient. A tympanogram may also help with the diagnosis. Patulous Eustachian tube is likely if brisk inspiration causes a significant pressure shift.
Patulous Eustachian tube is frequently misdiagnosed as standard congestion due to the similarity in symptoms and rarity of the disorder. Audiologists are more likely to recognize the disorder, usually with tympanometry or nasally delivered masking noise during a hearing assessment, which is highly sensitive to this condition.[7]
When misdiagnosis occurs, a decongestant medication is sometimes prescribed. This type of medication aggravates the condition, as the Eustachian tube relies on sticky fluids to keep closed and the drying effect of a decongestant would make it even more likely to remain open and cause symptoms. The misdiagnosed patient may also have tubes surgically inserted into the eardrum, which increases the risk of ear infection and will not alleviate patulous Eustachian tube. If these treatments are tried and failed, and the doctor is not aware of the actual condition, the symptoms may even be classified as psychological.
Incidentally, patients who instead suffer from the even rarer condition of superior canal dehiscence are at risk for misdiagnosis of patulous Eustachian tube due to the similar autophony in both conditions.
Treatment
Estrogen nasal drops or saturated potassium iodide have been used to induce edema of the eustachian tube opening. Nasal medications containing diluted hydrochloric acid, chlorobutanol, and benzyl alcohol have been reported to be effective in some patients, with few side effects. Food and Drug Administration approval is still pending, however.[8] Nasal sprays have also been a very effective temporary treatment for this disease, as well.[9]
In extreme cases surgical intervention may attempt to restore the Eustachian tube tissues with fat, gel foam, or cartilage or scar it closed with cautery. These methods are not always successful. For example, there is the case of the early attempts at surgical correction involving the injections of tetrafluoroetheylene (Teflon) paste but, although this treatment was able to give transient relief, it was discontinued due to several deaths that resulted from inadvertent intracarotid injections.[10]
References
- Dornhoffer, John; Gluth, Michael (2016). The Chronic Ear. Stuttgart: Thieme. ISBN 9781604068658.
- Gopen, Quinton (2013). Fundamental Otology: Pediatric and Adult Practice. New Delhi: Jaypee Brothers Medical Publishers Pvt. Ltd. p. 181. ISBN 9789350902691.
- Sataloff, Joseph; Sataloff, Robert (2005). Hearing Loss, 4th ed. Boca Raton, FL: CRC Press. p. 186. ISBN 9780824754358.
- Gulya, Aina; Minor, Lloyd; Poe, Dennis (2010). Glasscock-Shambaugh Surgery of the Ear 6th ed. Shelton, CT: PMPH-USA. p. 252. ISBN 9781607950264.
- Patulous Eustachian Tube Overview at eMedicine
- Hillman, Edawrd J. (1995). Otolaryngologic Manifestations Of Pregnancy. BCM
- Hori, Y., Kawase, T., Hasegawa, J., Sato, T., Yoshida, N., et al. (2006). Audiometry with nasally presented masking noise: Novel diagnostic method for patulous eustachian tube. Otol Neurotol, 27, 596-599.
- Patel, K and Levine S (July 31, 2010). "Emedicine - Patulous Eustachian Tube".
- "Patulous Eustachian Tube | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program". rarediseases.info.nih.gov. Retrieved 2018-12-12.
- Snow, James; Ballenger, John Jacob (2009). Ballenger's Otorhinolaryngology: Head and Neck Surgery. Sheldon, CT: PMPH-USA. p. 207. ISBN 9781550093377.