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Description
Otitis media is an infection or inflammation of the
middle ear. This inflammation often begins when infections
that cause sore throats, colds, or other respiratory
or breathing problems spread to the middle ear. Seventy-five
percent of children experience at least one episode
of otitis media by their third birthday. Almost half
of these children will have three or more ear infections
during their first three years. Although otitis media
is primarily a disease of infants and young children,
it can also affect adults.
Click
here for a more indepth picture of the anatomy of the
ear courtesy of Beltone.
The ear consists of three major parts:
the outer ear, the middle ear and the inner ear. The
outer ear includes the pinnaóthe visible part
of the earóand the ear canal. The outer ear extends
to the tympanic membrane or eardrum, which separates
the outer ear from the middle ear. The middle ear is
an air-filled space that is located behind the eardrum.
The middle ear contains three tiny bones, the malleus,
incus and stapes, which transmit sound from the eardrum
to the inner ear. The inner ear contains the hearing
and balance organs. The cochlea contains the hearing
organ, which converts sound into electrical signals,
which are associated with the origin of impulses carried
by nerves to the brain where their meanings are appreciated.
Otitis media not only causes severe pain
but also may result in serious complications if it is
not treated. The hearing loss caused by otitis media
is usually temporary, but untreated otitis media may
lead to permanent hearing impairment, though it is rare.
Persistent fluid in the middle ear and chronic otitis
media can reduce a child's hearing at a time that is
critical for speech and language development. Children
who have early hearing impairment from frequent ear
infections are likely to have speech and language disabilities.
Causes/Diagnosis
Otitis media usually results from a bacterial or viral
infection secondary to a cold, sore throat or other
respiratory problem.
Otitis media is often difficult to detect because
most infants and young children affected by this disorder
do not yet have sufficient speech and language skills
to tell someone what is bothering them. Common signs
to look for are:
- unusual irritability,
- difficulty sleeping,
- tugging or pulling at one or both ears,
- fever,
- fluid draining from the ear,
- loss of balance,
or unresponsiveness to quiet sounds or other signs
of hearing difficulty such as sitting too close to the
television or being inattentive.
The simplest way to detect an active infection in
the middle ear is to look in the child's ear with an
otoscope, a light instrument that allows the physician
to examine the outer ear and the eardrum. Inflammation
of the eardrum indicates an infection. There are several
ways that a physician checks for middle ear fluid. The
use of a special type of otoscope called a pneumatic
otoscope allows the physician to blow a puff of air
onto the eardrum to test eardrum movement. (An eardrum
with fluid behind it does not move as well as an eardrum
with air behind it.)
A useful test of middle ear function is called tympanometry.
This test requires insertion of a small soft plug into
the opening of the child's ear canal. The plug contains
a speaker, microphone and a device that is able to change
the air pressure in the ear canal, allowing for several
measures of the middle ear. The child feels air pressure
changes in the ear or hears a few brief tones. While
this test provides information on the condition of the
middle ear, it does not determine how well the child
hears. A physician may suggest a hearing test for a
child who has frequent ear infections to determine the
extent of hearing loss. An audiologist, a person who
is specially trained to measure hearing, usually performs
the hearing test.
Why are more children
affected by otitis media than are adults?
There are many reasons why children are more likely
to suffer from otitis media than adults. First, children
have more trouble fighting infections. This is because
their immune systems are still developing. Another reason
has to do with the child's Eustachian tube. The Eustachian
tube is a small passageway that connects the upper part
of the throat to the middle ear. It is shorter and straighter
in the child than in the adult. It can contribute to
otitis media in several ways.
The Eustachian tube is usually closed but opens regularly
to ventilate or replenish the air in the middle ear.
This tube also equalizes middle ear air pressure in
the environment. However, a Eustachian tube that is
blocked by swelling of its lining or plugged with mucus
from a cold or for some other reason cannot open to
ventilate the middle ear. The lack of ventilation may
allow fluid from the tissue that lines the middle ear
to accumulate. If the Eustachian tube remains plugged,
the fluid cannot drain and begins to collect in the
normally air-filled middle ear.
One more factor that makes children more susceptible
to otitis media is that adenoids in children are larger
than they are in adults. Adenoids are composed largely
of cells (lymphocytes) that help fight infections. They
are positioned in the back of the upper part of the
throat near the Eustachian tubes. Enlarged adenoids
can, because of their size, interfere with the Eustachian
tube opening. In addition, adenoids may themselves become
infected, and the infection may spread into the Eustachian
tubes.
Bacteria reach the middle ear through the lining or
the passageway of the Eustachian tube and can then produce
infection which causes swelling of the lining of the
middle ear, blocking of the Eustachian tube and the
migration of white cells from the bloodstream to help
fight the infection. In this process the white cells
accumulate, often killing bacteria and dying themselves,
leading to the formation of pus, a thick yellowish-white
fluid in the middle ear. As the fluid increases, the
child may have trouble hearing because the eardrum and
middle ear bones are unable to move as freely as they
should. As the infection worsens, many children also
experience severe ear pain. Too much fluid in the ear
can put pressure on the eardrum and eventually tear
it.
Prevention
Specific prevention strategies applicable to all infants
and children such as immunization against viral respiratory
infections or specifically against the bacteria that
cause otitis media are not currently available. Nevertheless,
it is known that children who are cared for in-group
care settings as well as children who live with adults
who smoke cigarettes have more ear infections. Therefore
a child who is prone to otitis media should avoid contact
with sick playmates and environmental tobacco smoke.
Infants who nurse from a bottle while lying down also
appear to develop otitis media more frequently. Children
who have been breast fed often have fewer episodes of
otitis media. Research has shown that cold and allergy
medications such as antihistamines and decongestants
are not helpful in preventing ear infections. The best
hope for avoiding ear infections is the development
of vaccines against the bacteria that most often cause
otitis media. Scientists are currently developing vaccines
that show promise in preventing otitis media. Additional
clinical research must be completed to ensure their
effectiveness and safety.
Treatment
Most physicians recommend the use of an antibiotic (a
drug that kills bacteria) when there is an active middle-ear
infection. If a child is experiencing pain, the physician
may also recommend a pain reliever. Once started, the
antibiotic usually must be given to the child regularly
for 10 to 14 days. Most physicians have the child return
for a follow up examination 10 to 14 days after the
start of the antibiotic to see if the infection has
cleared. Unfortunately, there are many bacteria that
can cause otitis media and some have become resistant
to some antibiotics. Several different antibiotics may
have to be tried before an ear infection clears. Antibiotics
may also produce unwanted side effects such as nausea,
diarrhea and rashes.
Once the infection clears, fluid may remain in the
middle ear for several months. Middle-ear fluid that
is not infected often disappears after three to six
weeks. Neither antihistamines nor decongestants are
recommended as helpful in the treatment of otitis media
at any stage in the disease process. Sometimes physicians
will treat the child with an antibiotic to hasten the
elimination of the fluid. If the fluid persists for
more than three months and is associated with a loss
of hearing, many physicians suggest the insertion of
"tubes" in the affected ears. This operation,
called a myringotomy, can usually be done on an outpatient
basis by a surgeon, who is usually an otolaryngologist
(a physician who specializes in the ears, nose and throat).
While the child is asleep under general anesthesia,
the surgeon makes a small opening in the child's eardrum.
A small metal or plastic tube is placed into the opening
in the eardrum. The tube ventilates the middle ear and
helps keep the air pressure in the middle ear equal
to the air pressure in the environment. The tube normally
stays in the eardrum for six to twelve months after
which time it usually comes out spontaneously. If a
child has enlarged or infected adenoids, the surgeon
may recommend removal of the adenoids at the same time
the ear tubes are inserted. Removal of the adenoids
has been shown to reduce occurrences of otitis media.
Tonsillectomy and adnoidectomy may be appropriate for
reasons other than middle-ear fluid.
Hearing should be fully restored once the fluid is
removed. Some children may need to have the operation
again if the otitis media returns after the tubes come
out. While the tubes are in place, water should be kept
out of the ears. Many physicians recommend that a child
with tubes wear special earplugs while swimming or bathing
so that water does not enter the middle ear.
Research
Several avenues of research are being explored to further
improve the prevention, diagnosis and treatment of otitis
media. For example, research is better defining those
children who are at high risk for developing otitis
media and conditions that predispose certain individuals
to middle ear infections. Emphasis is being placed on
discovering the reasons why some children have more
ear infections than other children. The effects of otitis
media on children's speech and language development
are important areas of study as well as research to
develop more accurate methods to help physicians detect
middle-ear infections. How the defense molecules and
cells involved with immunity respond to bacteria and
viruses that often lead to otitis media is also under
investigation. Scientists are evaluating the success
of certain drugs currently being used for the treatment
of otitis media and are examining new drugs that may
be more effective, easier to administer and more adequately
prevent new infections. Most importantly, research is
leading to the availability of vaccines that will prevent
otitis media.
**There is ongoing scientific
discussion about the use of antibiotic therapy for otitis
media.
Source: National Institute on Deafness & Other
Communication Disorders, 2000.
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