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A DISCUSSION OF EUSTACHIAN TUBE PROBLEMS
MECHANISM OF HEARING
The ear is comprised of three portions: an outer ear (external),
a middle ear and inner ear. Each part performs an important
function in the process of hearing.
The outer (external) ear consists of an auricle and ear canal.
These structures gather the sound and direct it toward the
ear drum (tympanic membrane).
The middle ear chamber lies between the external and inner
ear. This chamber is connected to the back of the throat (pharynx)
by the eustachian tube which serves as a pressure equalizing
valve. The middle ear consists of an eardrum and three small
ear bones (ossicles): malleus (hammer), incus (anvil) and
stapes (stirrup). These structures transmit sound vibrations
to the inner ear. In so doing, they act as a transformer,
converting sound vibrations in the external ear canal into
fluid waves in the inner ear. A disturbance of the eustachian
tube, eardrum or the ear bones may result in a conductive
hearing impairment. This type of impairment is usually corrected
medically or surgically.
The inner ear (cochlea) contains the microscopic hearing nerve
endings (hair cells) bathed in fluid. Inner ear fluid waves
move the delicate nerve endings which in turn transmit sound
energy to the brain by the hearing nerve, where it is interpreted
into sound. A disturbance in the inner ear fluids or nerve
endings may result in a sensorineural hearing impairment.
Most often this type of hearing impairment is due to a hair
cell loss. This type of impairment is not correctable with
surgery.
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, you may help avoid ear difficulty
be observing the following recommendations:
1. Obtain from your druggist the following items: Sudafed
tablets and a plastic squeeze bottle of 1/4 percent NeoSynephrine
or Afrin nasal spray.
2. Following the container directions, begin taking Sudafed
tablets the day before your air flight. Continue the medication
for 24 hours after the flight if you have experienced any
problems equalizing your middle ear pressure.
3. Following the container directions, use the nasal spray
shortly before boarding the aircraft. Should your ears "plug
up" upon ascent, hold your nose and swallow while attempting
to force air up to the back of the throat. This will help
suck excess air pressure out of the middle ear.
4. Forty five minutes before the aircraft is due to land,
again use the nasal spray every five minutes for fifteen minutes.
Chew gum to stimulate swallowing. Should your ear "plug
up" despite this, hold your nose and blow gently toward
the back of the throat while swallowing. This will blow air
up the eustachian tube into the middle ear (Valsalva Maneuver).
None of these recommendations or precautions needs to be followed
if you have a middle ear ventilation tube (PE tube) in your
eardrum (tympanic membrane).
SEROUS OTITIS MEDIA
Serous otitis media is a term which is used to describe a
collection of fluid in the middle ear. This may be a recent
onset (acute) or may be long standing (chronic).
Serous otitis media is the most common cause of hearing loss
in children. Fortunately, the hearing loss associated with
this condition usually is not permanent. Proper treatment
restores the hearing to a normal level and prevents secondary
complications, which can give rise to a more serious problem.
In serous otitis media, the external and inner ear and hearing
nerve are normal. The problem stems from inadequate function
of the Eustachian tube. The tube becomes blocked and does
not allow air to fill the middle ear space. Subsequently,
fluid (called serous fluid) forms from the middle ear lining
and collects in the space (fig. 2). The presence of this serous
fluid limits or "dampens" the vibration of the eardrum
and causes a mild to moderate hearing impairment. This fluid
makes the ear more susceptible to recurrent ear infections
in many children. The trapped fluid is an ideal place for
bacteria to grow and reproduce rapidly. Therefore, bacteria
entering the middle ear space easily cause a purulent infection;
the pus produced then exerts pressure on the eardrum with
resultant pain (earache).
However, serous otitis media may be present without recurrent
ear infections and a mild hearing loss may be the only sign
of its presence.
Acute serous otitis media is 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 in the middle
ear until the eustachian tube again begins to function properly,
at which time the fluid is absorbed or drains down the tube
into the back of the throat.
Chronic serous otitis media may result from long standing
eustachian tube blockage or from a thickening of the fluids
so that it cannot be absorbed or drained down the tube. This
chronic condition is usually associated with a hearing impairment.
There may be recurrent ear pain, especially when the individual
catches a cold. Serous otitis may persist for many years without
producing any permanent damage to the middle ear mechanism.
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.
CAUSE 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 mechanical blockage
of the tube.
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 a small eustachian tube 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 the mucous membrane swelling, which in turn
may result in eustachian tube obstruction.
Allergy
Allergic reaction in the nose and throat result in swelling
of the mucous membranes and this swelling may also affect
the eustachian tube. This reaction may be acute or chronic.
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, antihistamines
(anti-allergy drugs), decongestants (drugs 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 pharyngitis, fluid in the middle ear
may become infected. This results in what is commonly called
an abscessed ear or an infected middle ear.
This infected fluid (pus) in the middle ear may cause severe
pain. If examination reveals that there is considerable ear
pressure, a myringotomy (incision of the eardrum membrane)
may be necessary to relieve the abscess, and the pain. In
many instances antibiotic treatment will suffice.
Should a myringotomy be necessary, the ear may drain pus and
blood for several days. The tympanic membrane then heals and
the hearing usually returns to normal within three to four
weeks.
Antibiotic treatment, with or without a 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.
CHRONIC SEROUS OTITIS MEDIA
Treatment of chronic serous otitis media may either be medical
or surgical.
Medical Treatment
As the acute upper respiratory infection subsides, it may
leave the patient with a persistent eustachian tube blockage.
Antibiotic treatment may be indicated.
Allergy is often a major factor in the development or persistence
of serous otitis media. Mild cases can be treated with antihistaminic
drugs. More persistent cases may require allergic evaluation
and treatment, including injection treatment.
In connection with medical treatment, often eustachian tube
inflation is recommended. This is done by closing the nostrils
with your fingers and blowing air toward the back of the throat
while swallowing. This air goes up the eustachian tube and
re-establishes the middle ear air. Children often cannot do
this but often can achieve the same results by blowing balloons.
Surgical Treatment
The primary objective of surgical treatment of chronic serous
otitis media is to re-establish ventilation of the middle
ear, or equalize pressure of the middle ear with that in the
ear canal. This keeps the hearing at a normal level and prevents
recurring infections that might damage the tympanic membrane
and middle ear bones. This involves a myringotomy with aspiration
of fluid and insertion of a ventilation tube.
A myringotomy (incision in the eardrum) is performed to remove
the middle ear fluid. A hollow plastic tube or metal 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 tube usually remains
in place for six to nine months, during which time the eustachian
tube blockage should subside. The tubes can be removed at
a later date, but most of the time it is preferable to let
the tubes work their way out of the eardrum. When the tube
dislodges, the eardrum heals: the eustachian tube then resumes
its normal pressure equalizing function. In rare instances
(less than 5% of cases) the eardrum membrane does not heal
following extrusion of the tube. The perforation may be repaired
at a later date if this occurs. Usually this small perforation
poses no problem, as it also would act as a ventilation tube.
In adults, a myringotomy and insertion of a ventilation tube
is usually performed in the office under local anesthesia,
with the use of a topical solution placed on top of the tympanic
membrane. In children, general anesthesia is required.
Most often when the ventilation tube is extruded there is
no further middle ear ventilation problem. Should recurrent
serous otitis media occur, reinsertion of a tube may be necessary.
In some difficult cases it is necessary to insert a more permanent
type of tube.
When a ventilation tube is in place, a patient may carry on
normal activities with the exception that no water must enter
the ear canal. Often this can be prevented with vaseline on
a cotton ball or Silly Putty can be used to provide occlusion
of the ear canal. In addition a custom made earmold will often
prevent water from entering the ear canal.
One should be reminded that the purpose of a ventilation tube
is not to drain the fluid in the middle ear space. This fluid
is drained at the time of the surgery. The purpose of a tube
is to equalize the pressures across the eardrum. This prevents
the reoccurrence of fluid in the middle ear and re-establishes
normal middle ear function.
CHRONIC SEROUS MASTOIDITIS AND IDIOPATHIC HEMOTYMPANUM
Chronic serous mastoiditis and idiopathic hemotympanm are
uncommon conditions which 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 may become dislodged
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 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.
PALATAL MYOCLONUS
Palatal myoclonus is a rare condition in which the muscles
of the palate (back of the mouth) twitch rhythmically many
times a minute. The cause of this harmless muscle spasm is
unknown. Often it is triggered with eating some foods or drinking
hot or cold liquids.
The patient may experience a rhythmic clicking or snapping
sound in the ear as the eustachian tube opens and closes.
On occasion, this snapping sound is caused by a simultaneous
spasm of a muscle in the middle ear attached to the ear bones.
A muscle relaxant is often effective in controlling the symptoms.
When they persist and if they continue to pose a problem for
the patient, surgery is sometimes recommended. Cutting the
muscle in the middle ear usually relieves the symptoms.
If surgical treatment is necessary, it is performed under
local anesthesia through the ear canal. Hospitalization is
necessary for one night following surgery, and the patient
may return to his usual activities in several days.
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