出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/02/27 10:49:13」(JST)
| Patulous Eustachian tube | |
|---|---|
| Classification and external resources | |
| Specialty | otolaryngology |
| ICD-10 | H69.0 |
| ICD-9-CM | 381.7 |
| eMedicine | ent/359 |
|
[edit on Wikidata]
|
|
Patulous Eustachian tube, also known as patent Eustachian tube, is the name of a physical disorder where the Eustachian tube, which is normally closed, instead stays intermittently open. When this occurs, the patient 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.
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.
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. 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.[1]
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 mucous in the respiratory system.[2]
| This article may require cleanup to meet Wikipedia's quality standards. No cleanup reason has been specified. Please help improve this article if you can. (August 2011) |
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.[3]
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.
Patulous Eustachian Tube (PET) or tube to open remains an ET dysfunction category, difficult to diagnose and to treat. Recent studies suggest that the pathophysiology and etiology of PET is more related to a previous history of otitis media, rather than from weight loss, which was widely recognized as the major causal factor. Simultaneous weight gain can even be observed in some cases. The average age is 30 years, with a female prevalence. It’s rare to find patients of less than 15 years of age, which seems to confirm the opinion that PET is an acquired condition. Chronic upper respiratory inflammatory diseases are almost always associated with PET ; half of these patients report previous history of nasal or sinus surgery. Radical posterior / inferior turbinectomies seem to be proportionally connected to PET severity. History of recurrent otitis media with effusion, with tympanostomy and adenoidectomy during childhood is also frequent. Laryngopharyngeal reflux (LPR) is identified in a great proportion of patients. Last epidemiological data indicates that PET results from obstructive ET dysfunction evolving over a long period of time.
Since the surgical management of these two pathologies is at diametrically opposed extremes, it is critical to obtain the correct diagnosis before undertaking any treatment. Visualization of a permanently open tubal valve by endoscopic examination allows settling this question, but its absence does not exclude PET diagnosis. Sonotubometry and recently developed tubomanometry may help in some specific cases. Unfortunately, some PET cases remain difficult to diagnose.
| This article may require cleanup to meet Wikipedia's quality standards. No cleanup reason has been specified. Please help improve this article if you can. (March 2012) |
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 “from inside”. 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.
With time patients may develop respiratory autophonia. At this stage, they hear “from inside”. They describe hearing their own respiration and sometimes other bodily functions, like heartbeat. Some patients may find this unbearable and depression is common. Psychological supervision may be indicated.
Historically, to temporarily alleviate symptoms, patients have tried positional maneuvers, such as tilting their head to one side or upside down, lie down on their backs, or sit in a chair with their head between their knees. Similarly, a routine of lying down four times per day with legs elevated to around 20 inches for at least two weeks has been attempted as well. Depending on the underlying cause of the disorder, the individual may need to remove caffeine from their diet, reduce exercise, or gain weight. It may be the case that the symptoms are induced by anxiety; anxiolytic drugs or supplements (e.g., GABA) combined with the removal of caffeine from the diet could offer a simple strategy to determine if anxiety is the root cause.
Estrogen (Premarin) 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.[4]
In extreme cases surgical intervention may attempt to "power up" the Eustachian tube tissues with fat, gel foam, or cartilage or scar it closed with cautery. These methods are not always successful.
全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.
| リンク元 | 「耳管開放症」 |
| 関連記事 | 「tube」「eustachian tube」 |