Patulous Eustachian tube | |
---|---|
Classification and external resources | |
Specialty | otolaryngology |
ICD-10 | H69.0 |
ICD-9-CM | 381.7 |
eMedicine | ent/359 |
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.
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.
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.