FUNCTION OF THE EUSTACHIAN TUBE
The eustachian tube is a narrow channel which connects the middle ear with the nasopharynx (the upper throat area just above the palate, in back of the nose). The Eustachian tube is approximately 1 1/2 inches in length. The narrowest portion is that area near the middle ear space.
The eustachian tube functions as a pressure equalizing valve of the middle ear, which is normally filled with air. Under normal circumstances the eustachian tube opens for a fraction of a second in response to swallowing or yawning. In so doing it allows air into the middle ear to replace air that has been absorbed by the middle ear lining (mucous membrane) or to equalize pressure changes occurring with altitude changes. Anything that interferes with this periodic opening and closing of the eustachian tube may result in a hearing impairment or other ear symptoms.
Obstruction or blockage of the eustachian tube results in a negative middle ear pressure, with restraction (sucking in) of the eardrum (tympanic membrane). In an adult this is usually accompanied by some discomfort, such as a fullness or pressure feeling, and may result in a mild hearing impairment and head noise (tinnitus). In children there may be no symptoms. If the obstruction is prolonged, the fluid may be sucked in from the mucous membrane in the middle ear creating a condition called serous otitis media (fluid in the middle ear). This occurs frequently in children in connection with an upper respiratory infection or allergies and accounts for the hearing impairment associated with this condition.
On occasion just the opposite from blockage occurs; the tube remains open for a prolonged period. This is called abnormal patency of the eustachian tube (patalous eustachian tube). This is less common than serous otitis media and occurs primarily in adults. Because the tube is constantly open the patient may hear himself breathe and hears his voice reverberate in the affected ear. Fullness and a blocked feeling are not uncommon sensations experienced by the patient. Abnormal patency of the eustachian tube is annoying but does not produce a hearing impairment.
EUSTACHIAN TUBE PROBLEMS RELATED TO FLYING
Individuals with a eustachian tube problem may experience difficulty equalizing middle ear pressure when flying. When an aircraft ascends, the atmospheric pressure decreases, resulting in a relative increase in the middle ear air pressure. When the aircraft descends, just the opposite occurs; atmospheric pressure increases in the cabin of the aircraft and there is a relative decrease in the middle ear pressure. Either situation may result in discomfort in the ear due to abnormal middle ear pressure compared to the cabin pressure, if the eustachian tube is not functioning properly. Usually, this discomfort is experienced upon descent of the aircraft.
To avoid middle ear problems associated with flying you should not fly if you have an acute upper respiratory problem such as a common cold, allergy attack or sinus infection. Should you have such a problem and must fly, or should have a chronic eustachian tube problem, seek an opinion from your otolaryngologist or audiologist.
THE ABNORMALLY PATENT EUSTACHIAN TUBE
Abnormal patency of the eustachian tube is a condition occurring primarily in adults, in which the eustachian tube remains "open" for a prolonged period. This abnormality may produce many distressing symptoms such as ear fullness and blockage, a hollow feeling in the ear, hearing one’s own breathing and voice reverberation in the ear. It does not produce a hearing impairment although most patients will feel that they cannot hear as well in that ear.
The exact cause of an abnormally patent eustachian tube is often difficult to determine. At times it develops following a loss in weight or may develop during pregnancy. It may also occur while taking oral contraceptives or other hormones.
Treatment of this harmless condition is often difficult. Medical or surgical treatment is often directed towards causing mechanical obstruction of the eustachian tube or creating a less functional eustachian tube.
