Eustachian Tube Problems

Eustachian Tube Problems

Mechanism of Hearing

There are three parts to the ear: the external ear, the middle ear, and the inner ear.  Each part performs and important function in the process of hearing.

The external ear consists of an auricle and ear canal.  These structures gather sound and direct it towards the ear drum (tympanic membrane), which separates the external ear from the middle ear.

The middle ear lies between the ear drum and the inner ear.  This chamber is connected to the back of the nose by the eustachian tube.  The eustachian tube serves as a pressure regulating valve for the middle ear.  The middle ear contains three hearing bones: the malleus (hammer), incus (anvil), and stapes (stirrup).  These bones are known as ossicles and are the smallest bones in the body.  Vibration of the ear drum causes movement of the hearing bones.  The stapes interfaces with the fluid that fills the inner ear (or cochlea), and its movement causes a fluid wave to pass through the inner ear.

The inner ear is contained within the densest bone in the body.  This fluid wave generated by the ossicles causes movement of tiny hair cells within the cochlea.  When those hair cells are displaced they generate an electrical signal that is transmitted by the hearing nerve to the brain where it processed.

Types of Hearing Loss

Since the external and middle ear conduct sound.  If there is a problem with external or middle ear it was cause a conductive hearing loss.  The inner ear creates the electrical signal and transmits it through the nerve.  If there is a problem in the inner ear, a sensorineural hearing loss results.  When the problem effects both systems it creates a mixed hearing loss.

Function of 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 functions as a pressure equalizing valve for the middle ear which is normally filled with air.  When functioning properly the eustachian tube opens for a fraction of a second periodically (about once every three minutes) 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 membranes) or to equalize pressure changes occurring due to altitude changes.  Anything that interferes with this periodic opening and closing of the eustachian tube may result in hearing impairment or other ear symptoms.

Obstruction or blockage of the eustachian tube results in a negative middle ear pressure, which will cause the ear drum to retract (suck in).  In adults this is usually accompanied by some ear discomfort, a fullness or pressure feeling and may result in a mild hearing impairment and ringing in the ear (tinnitus).  There may be no symptoms in children.  If the obstruction is prolonged, fluid may be drawn from the mucous membranes of the middle ear creating a condition we call serous otitis media (fluid in the middle ear).  This occurs frequently in children in connection with an upper respiratory infection and accounts for the 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 often temporary and often can be avoided by taking precautions (see following section).

On occasions just the opposite from blockage occurs: the tube remains open for prolonged periods.  This is called abnormal patency of the eustachian tube, or patulous eustachian tube.  This condition 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 their voice reverberate.  Fullness and a clocked feeling are not uncommon.  Abnormal patency of the Eustachian tube is annoying but does not produce hearing impairment.

Eustachian Tube Problems Related to Flying

Individuals with a eustachian tube problem may have trouble 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.  Usually this discomfort is experienced during descent.

To avoid middle ear problems related to flying it is best to try not to fly if you have an acute upper respiratory problem such as a cold, allergy attack, or sinus infection.  If you must fly, or you have a chronic problem with your eustachian tube problem, you may help to avoid problems with the following tips:

  1. Purchase Sudafed tablets and Neo-synephrine nasal spray from the pharmacy (over the counter).
  2. Following the package instructions, start taking the Sudafed the day before your flight and continue to take it for 24 hours after if you have any ear difficulty.
  3. Following the package instructions, use the nasal spray shortly before boarding. 
  4. If your ears “plug up” on ascent, hold your nose and swallow.  This will help equalize the pressure.
  5. 45 minutes before the aircraft is due to land use the nasal spray every five minutes for fifteen minutes.
  6. Chew gum to stimulate swallowing.  If your ears “plug up” pinch your nose and blow forcibly try to blow air out your plugged nose.  This will direct air up the eustachian tube into the middle ear (called a Valsalva maneuver). 

Acute Suppurative Otitis Media

In children, the eustachian tube is more horizontally oriented than in adults.  This allows bacteria from the nasopharynx easier passage into the middle ear space.  This may cause an infection in the middle ear space and is what most people think of then they think of an ear infection.

Adults can also have acute suppurative otitis media.  Generally, this happens when the Eustachian tube is blocked by an upper respiratory infection or allergies and the fluid that develops behind the ear drum becomes infected with bacteria.

This infected fluid (pus) in the middle ear may cause severe pain as it causes the ear drum to bulge.  If examination reveals that there is considerable ear pressure a myringotomy (incision of the ear drum) may be necessary to relieve the pressure and drain the abscess.  In many cases antibiotics by mouth will suffice.

Should a myringotomy be required the ear may drain pus and blood for up to a week.  Antibiotics drops are effective after myringotomy.  If, after the drops are instilled into the ear canal, gentle pressure is applied to the tragus (the small lobe of the ear in front of the ear canal) in a series of “pumps” to help the antibiotics through the ear drum into the middle ear space where the infection is.  The myringotomy typically heals within 7-14 days.

Antibiotic treatment usually results in normal middle ear function within three to four weeks.  During the healing period there are varying degrees of ear pressure, popping, clicking and fluctuation of hearing – with occasional shooting pains.

Sometimes, after the acute infection has resolved, the patient is left with uninfected fluid in the middle ear space.  This uninfected fluid is known as serous otitis media.

Serous Otitis Media

Serous otitis media means that there is a collection of fluid in the middle ear.  It may be chronic or acute.  90% of the time, fluid behind the ear drum will resolve on its own within three months.  Within that three month period, it is known as “acute”.  It either drains down the eustachian tube when it finally opens or is absorbed by the mucosa of the middle ear.

When it persists beyond three months, it is known as “chronic”.  Serous otitis media may persist for many years without causing any permanent damage to the middle ear mechanism.  The fluid, however, increases susceptibility to recurrent bacterial infections which may damage the middle ear structures.  In addition, while the fluid is in the middle ear it interferes with the transmission of sound through the middle ear causing a conductive hearing loss.

Causes of Serous Otitis Media

Any condition the interferes with the intermittent opening and closing of the eustachian tube can lead to serous otitis media.  The causes may be congenital (present at birth), due to infection or allergy, or due to blockage of the eustachian tube.

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.  There seems to be a hereditary component – parents of children with eustachian tube problems often have a history of otitis media in childhood.  As a child matures the eustachian tube takes on a more adult shape.

Cleft Palate

Serous otitis media is more common in the child with a cleft palate.  This is because the muscles  the move the palate are the muscles that open the eustachian tube.  These muscles are deficient and/or abnormal in children with a cleft palate.

Infection

The lining membrane of the middle ear and eustachian tube is the same as the membranes of the nose, sinuses, and throat.  Infection in these areas results in mucous membrane swelling which may lead to obstruction.

Allergy

Allergic reactions in the nose and throat lead to mucous membrane swelling, which may affect the eustachian tube. 

Adenoids

The adenoids are located in the nasopharynx in the area between the eustachian tube openings.  When enlarged, the adenoids my block the opening of the eustachian tube.

Acute Serous Otitis Media

Treatment of acute serous otitis media is medical and is directed towards treatment of the upper respiratory infection or allergies.  This may include antihistamines and decongestants.

Chronic Serous Otitis Media

Treatment of chronic serous otitis media is either medical or surgical.

Medical Treatment

If an acute upper respiratory in present, it may be addressed with antibiotics.  Allergies, if seasonal, may be managed with oral anti-histamines or decongestants.  More persistent cases may require allergic evaluation and treatment which may include immunotherapy.

In connection with medical treatment, it is recommended that the patient learn to regularly inflate the eustachian tube.  This is done with the Valsalva or Toynbee maneuvers.  Patients often find one or the other to work better.  Try both.

The Valsalva maneuver is accomplished by pinching the nostrils closed, then forcibly blowing through the closed nose.  This will force air into the middle ear.  It is often referred to as “popping the ears”. 

The Toynbee maneuver is performed by pinching closed the nose and swallowing.  This will also force the eustachian tube open.

Surgical Treatment

The primary objective of surgical treatment of chronic serous otitis media is to re-establish ventilization of the middle ear, with the intent of keeping the hearing at a normal level and preventing recurring infection.  This involves myringotomy with insertion of a ventilization tube.  At times, an adenoidectomy may be recommended.

Myringotomy

Myringotomy (incision of the ear drum) allows the fluid to be removed from the middle ear space with gentle suctioning.  A hollow plastic tube (ventilization tube) is inserted into the ear drum to ensure the ear drum stays open and allows ventilization.  The ventilization tube temporarily takes the place of the eustachian tube and equalizes the middle ear pressure.  The tube typically remains in place for six to twelve months, during which time the eustachian tube blockage should have resolved.  The ear drum extrudes the tube as it heals, and once the ear drum is healed the eustachian tube resumes its normal function.

Approximately 2 in 100 patients will have a persistent hole in the ear drum after the tube extrudes.  Or, the tube does not extrude.  Either case may require an additional procedure to correct.

In adults myringotomy and tube placement are performed in the office under local anesthesia.  In children general anesthesia is required.  The adenoids, if enlarged, can be removed at the same time.

When a ventilization tube is present the patient may carry on normal activities, with some water precautions.  The narrow lumen of the tube allows the surface tension of the water to prevent passage through the tube when swimming on the surface of the water.  You should not dive deeper than two feet.  At that depth the pressure will force water through the ventilization tube.  When showering, care should be taken not to allow water to spray directly into the ear canal.  When taking a bath, a cotton ball with a small layer of Vaseline should be placed in the ears.  Bath water passes through the tube more readily because the soap decreases the surface tension.

Chronic Non-suppurative Otitis Media

When the eustachian tube does not open to allow the middle ear space to ventilate for a prolonged period of time, negative pressure is generated in the middle ear space as the mucous membranes absorb the air from the middle ear.  The ear drum is a very thin membrane.  Therefore, as the negative pressure develops the ear drum is retracted (sucked in).  Normally, of the three hearing bones, only the malleus touches the ear drum.  As the ear drum retracts it may make contact with the other two hearing bones.  These bones are so small that the pressure of the ear drum is enough to cause them to erode.  This may lead to a conductive hearing loss.  Although, occasionally the retracted drum will make direct contact with the stapes and allow sound transmission directly through he stapes into the inner ear.

There is an area of the ear drum that is less tense than the majority of the ear drum.  This area is called the pars flaccida.  This area is particularly susceptible to retraction.  At some point, a retraction will get deep enough that it will begin to collect skin debris.  This accumulation of skin debris is called a cholesteatoma (see chronic otitis media brochure).

Abnormally Patent Eustachian Tube (Patulous Eustachian Tube)

Patulous eustachian tube, where the eustachian tube remains “open” for prolonged periods of time, occurs primarily in adults.  This may produce many distressing symptoms: ear fullness and pressure, a hollow feeling, hearing your own breathing and voice reverberation.  It does not produce hearing loss.

The exact cause of a patulous eustachian tube is often difficult to determine.  At times it develops following a weight loss.  It may develop during pregnancy, or while taking oral contraceptives or other hormones.

Treatment of this harmless condition can be difficult.  Myringotomy with insertion of a ventilization tube may be effective.  There are a number of medications that may also help.

Idiopathic Eustachian Tube Dysfunction (ETD)

In many patients there is no clear explanation why the eustachian tube does not open spontaneously.  Since ETD may lead to other more serious issues, it is important to somehow restore function of the eustachian tube.  Recurrent placement of ventilation tubes is an option.  Another option is balloon eustachian tube dilation.  In this procedure an endoscope is used to direct a catheter through the nose into the opening of the eustachian tube in the nasopharynx. This catheter has a balloon at the end.  Once in position, the balloon is inflated.  This has been shown to be effective at restoring function of the eustachian tube in most patients.

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