FUNCTION OF THE NORMAL EAR
The ear is divided into three parts: the external ear, the middle ear, and the inner ear. Each part performs an important function in the process of hearing.
Sound waves pass through the canal of the external ear and vibrate the ear drum which separate the external from the middle ear. The three small bones in the middle ear (hammer or malleus, anvil or incus, and stirrup or stapes) act as a transformer to transmit energy of the sound vibrations to the fluids of the inner ear. Vibrations in these fluid stimulate the delicate nerve fibers. The hearing nerve then transmits impulses to the Brian where they are interpreted as understandable sound.
Types of Hearing Impairment
The external ear and the middle ear conduct sound; the inner ear receives it. If there is some difficulty in the external or middle ear, a conductive hearing loss occurs. If the trouble lies in the inner ear, a sensorineural or nerve hearing loss is the result. When there is difficulty in both the middle and inner ear, a combination of conductive and sensorineural impairment exists.
FUNCTION OF THE EUSTACHIAN TUBE
The middle ear chamber lies between the external and inner ear. This chamber is connected to the back of the throat by the eustachian tube. The eustachian tube is a narrow, one and a half inch long channel connecting the middle ear with the nasopharynx the upper throat area just above the palate, in the back of the nose.
The eustachian tube serves as a pressure equalizing valve for the middle ear which is normally filled with air. A disturbance of the eustachian tube may alter the pressure in the middle ear and interfere with sound transmission resulting in a conductive hearing impairment. This type of impairment is usually correctable medically or surgically.
When functioning properly, the eustachian tube opens for a fraction of a second periodically (about once every three minutes0 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 differences occurring with altitude changes. Anything that interferes with this periodic opening and closing of the eustachian tube may result in a conductive hearing impairment or other ear symptoms.
Obstruction or blockage of the eustachian tube results in a negative middle ear pressure, with retraction (sucking in) of the eardrum membrane. In the adult, this is usually accompanied by some ear discomfort, a fullness or pressure feeling and may result in a mild conductive hearing impairment and head noise (tinnitus). There may be no symptoms in children. If the obstruction is prolonged, fluid may be drawn form the mucous membrane of the middle ear creating a condition we call serous otitis media. This occurs frequently in children in connection with an upper respiratory infection and accounts for the conductive hearing impairment associated with this condition.
Occasionally pain or middle ear fluid develops when landing in an aircraft. This is due to failure of the eustachian tube to properly equalize the middle ear air pressure, and the condition is called aerotitis. It is temporary and often can be avoided by taking precautions (see following section).
On occassion, just the opposite from blockage occurs: the tube remains open for prolonged periods. This is called abnormal patency of the eustachian tube or patulous Eustahian tube. This condition is less common than serous otitis media and occurs primarily in adults. because the tube is constantly open, the patient may sense his/her own breathing and voice reverberate in the involved ear. Fullness and a blocked feeling are not uncommon. Abnormal patency of the eustachian tube may be annoying but does not produce 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, 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, 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 if the eustachian tube is not functioning properly. Usually, this discomfort is experienced upon aircraft descent.
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, allergic congestion, or sinus infection. If you must fly with an acute upper respiratory problem or if you suffer from more chronic eustachian tube problems, you may avoid difficulty by observing the following recommendations.
1. Obtain from your druggist (a prescription is not necessary) the following items: Sudafed or Actifed tablets” Afrin or Neo-Synephrine nasal spray.
2. Following the container directions, begin taking Sudafed or Actifed tablets the day before your air flight. Continue the medictaion for 24 hours after the flight if you have experienced any ear difficulty.
3. Follow the container directions, sue the Neo-Synephrine or Afrin nasal spray shortly before boarding the aircraft. Should your ears “plug up” upon ascent, hold your nose and swallow. This will help suck excess air pressure out of the middle ear.
4. 45 minutes before the aircraft is due to land again, use the nasal spray every 5 minutes for 15 minutes. Chew gun to stimulate swallowing. Should your ears “plug up” despite this hold your nose and blow gently to try to force air up the eustachian tube into the middle ear (Valsalva maneuver).
5. rememver that it is unwise to fly if you have an acute upper respiratory infection.
Should flying be necessary under these circumstances, do not perform the Valsalva maneuver mentioned above.
None of these recommendations or precautions need be followed if you have a middle ear ventilation tube in your eardrum membrane.
SEROUS OTITIS MEDIA
Serous otitis media is the term we use to describe a collection of fluid in the middle ear. this may be acute or chronic. Acute serous otitis media us usually the result of blockage of the eustachian tube from an upper respiratory infection or an attack of nasal allergy. In the presence of bacteria, this fluid may become infected, leading to an acute suppurative otitis media (infected or abscessed middle ear). When infection does not develop, the fluid remains until the eustachian tube again begins to function normally, at which time the fluid is absorbed or drains down the tube into the throat.
Chronic serous otitis media may result form long-standing eustachian tube blockage, or from thickening of the fluids so that it cannot be absorbed or drained down the tube. This chronic condition is usually associated with hearing impairment. There may be recurrent ear pain, especially when the individual catches a cold. Fortunately, serous otitis media may persist for many years without producing any permanent damage to the middle ear mechanism. The presence of fluid in the middle ear, however, makes it very susceptible to recurrent acute infections. These recurrent infections may result in middle ear damage.
Causes of Serous Otitis Media
Serous otitis media may result from any condition that interferes with the periodic opening and closing of the eustachian tube. The causes may be congenital (present at birth), may be due to infection or allergy, or may be due to blockage of the tube by adenoids.
The Immature Eustachian Tube
The size and shape of the eustachian tube is different in children than in adults. This accounts for the fact that serous otitis media is more common in very young children. Some children inherit small eustachian tubes from their parents; this accounts in part for the familial tendency to middle ear infection.
As the child matures, the eustachian tube usually assumes a more adult shape.
Cleft Palate
Serous otitis media is more common in the child with a cleft palate. This is due to the fact that the muscles that move the palate also open the eustachian tube. These muscles are deficient or abnormal in the cleft palate child.
Infection
The lining membrane (mucous membrane) of the middle ear and eustachian tube is connected with, and is the same as, the membrane of the nose, sinuses, and throat. Infection of these areas results in mucous membrane swelling which in turn may result in eustachian tube obstruction.
Allergy
Allergic reactions in the nose and throat result in mucous membrane swelling, and this swelling may also affect the eustachian tube. This reaction may be acute, as in a hay fever type reaction, or may be chronic, as in many varieties of “chronic sinusitis”.
Adenoids
The adenoids are located in the nasopharynx, in the area around and between the eustachian tube openings. When enlarged, the adenoids may block the eustachian tube opening.
ACUTE SEROUS OTITIS MEDIA
Treatment of acute serous otitis media is medical and is directed towards treatment of the upper respiratory infection or allergy attacks. This may include antibiotics, antihistaminics (anti-allergy drugs), decongestants (drug to decrease mucous membrane swelling) and nasal sprays.
ACUTE SUPPURATIVE OTITIS MEDIA
In the presence of an upper respiratory infection, such as a cold, tonsillitis or sinusitis, fluid in the middle ear may become infected. This results in what is commonly called an abscessed ear or an infected ear.
This infected fluid (pus) in the middle ear may cause severe pain. If examination reveals that there is considerable bulging of the ear drum due to increased middle ear pressure, a myringotomy (incision of the eardrum membrane) may be necessary to drain the abscess and relieve the pain and pressure. In most cases, antibiotic treatment will suffice.
Should myringotomy be necessary, the ear may drain pus and blood for up to a week. The drum membrane then heals, and the hearing usually returns to normal within three to four weeks.
Antibiotic treatment, with or without myringotomy, usually results in normal middle ear function within three to four weeks. During this healing period, there are varying degrees of ear pressure, popping, clicking and fluctuation of hearing, occasionally with shooting pains in the ear.
Resolution of the acute infection occasionally leaves the patient with uninfected fluid in the middle ear. This is called chronic serous otitis media and this condition may persist for several weeks.
CHRONIC SEROUS OTITIS MEDIA
Treatment of chronic serous otitis media may be either medical or surgical
Medical Treatment
As the acute upper respiratory infection subsides, it may leave the patient with a chronic sinus infection. Pus from the sinuses and nose drain over the eustachian tube opening in the nasopharynx, resulting in persistent eustachian tube blockage. Antibiotic treatment may be indicated.
General health factors are particularly important in regard to the child’s resistance to infection. A deficiency in some of the blood proteins (antibodies) may predispose your child to recurrent infections and prolonged colds. This rare condition can be addressed by your child’s pediatrician.
Allergy is often a major factor in the development or persistence of serous otitis media. mild cases can be treated with antihistamines. More persistent cases may require allergic evaluation and treatment.
In connection with medical treatment, we may recommend eustachian tube inflation, the blowing of air through the nose into the obstructed eustachian tube and middle ear to help relieve the congestion and reestablish middle ear ventilation. This is done by the Valsalva maneuver or by Politzerization.
The Valsalva maneuver is accomplished by forcibly blowing air into the middle ear while holding the nose, often called “popping the ear”. However, this should not be done if there is a cold and nasal discharge.
Polizerization is accomplished by blowing air with a special syringe (middle ear inflator) into the nostril while blocking the other, and at the same time swallowing. This forces the air into the eustachian tube and middle ear. This likewise should not be performed when a cold is present.
Surgical Treatment. The primary objective of surgical treatment of chronic serous otitis media is to reestablish ventilation of the middle ear, keeeping the hearing at a normal level and preventing recurrent infection that might damage the eardrum and middle ear bones. This involves a myringotomy (an incision in the eardrum membrane) with insertion of a ventilation tube and, at times, adenoidectomy.
Myringotomy is performed to remove middle ear fluid. A hollow plastic tube (ventilation tube) is inserted to prevent the incision from healing and to insure middle ear ventilation. The ventilation tube temporarily takes the place of the eustachian tube in equalizing middle ear pressure. This plasti tube usually remains in place for three to twelve months. After the tube falls out on its own, the eardrum heals and the eustachian tube then resumes its normal pressure equalizing function.
In rare cases, the eardrum does not heal following dislodgment of the tube. The perforation that remains may be repaired at a later date.
In adults, myringotomy and insertion of a ventilation tube is usually performed in the office under local anesthesia. In children, this procedure is performed under general anesthesia and in recurrent cases may be accompanied by an adenoidectomy.
More often than not when the ventilation tube dislodges, there is no further problem with middle ear ventilation. Should serous otitis media recur, reinsertion of a tube may be necessary. In some difficult cases, it is necessary to insert a more permanent type of ventilation tube. This tube usually remains in place until removed and is associated with a higher incidence of ear drum perforation. In children, removal may require an anesthetic.
When a ventilation tube is in place, the patient may carry on normal activities, with the exception that he/she must not allow water to enter the ear canal. Your doctor will recommend an ear plug for use when showering, washing the hair or swimming.
CHRONIC SEROUS MASTOIDITIS AND IDIOPATHIC HEMOTYMPANUM
Chronic serous mastoiditis and idiopathic hemotympanum are uncommon conditions that have the same symptoms as chronic serous otitis media. They differ in that the middle ear fluid continues to form, either draining out the ventilation tube or blocking it completely so that the tube dislodges shortly after surgery. This persistent fluid formation is due to changes in the mucous membrane of the middle ear and mastoid.
In both of the above conditions, mastoid surgery may be necessary to control the problem and reestablish a normal middle ear mechanism.
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 prolonged periods. This abnormality may produce many distressing symptoms: ear fullness and blockage, a hollow feeling, hearing one’s own breathing and voice reverberation. It does not produce hearing impairment.
The exact cause of an abnormally patent eustachian tube is often difficult to determine. At times it develops following weight loss. It may develop during pregnancy or while taking oral contraceptives of hormones.
Treatment of this harmless condition is often difficult. A number of different medications are at times successful in alleviating the symptoms. Myringotomy and insertion of a ventilation tube (as described under the surgical treatment of serous otitis media) is often effective.
PALATAL MYOCLONUS
Palatal myoclonus is a rare condition in which muscles of the palate (back of the mouth) twitch rhythmically many times a minute. The cause of this condition is unknown.
The patient may experience a rhythmic clicking or snapping sound in the ear as the eustachian tube opens and closes. Sedatives or tranquilizers often are effective in controlling the symptoms. Diagnostic evaluation by a Neurologist may sometimes be indicated. No treatment is needed in most cases.
Palatal myoclonus may be confused with muscular tinnitus, the snapping sound in the ear is caused by spontaneous spasm of the two muscles attached to the middle ear bones. Cutting one or both of these muscles usually relieves the symptoms. The operation is performed under local anesthesia through the ear canal.
GENERAL COMMENTS
If you decide NOT to have surgery performed at this time or if surgery is not advisable, you should have periodic examination, especially if the ear is draining. Untreated chronic ear disease may result in serious complications. Should you develop dull pain in or about the ear, increased discharge, dizziness, or weakness of the face, you should immediately consult your physician.