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Otitis Media
Ear
Infection
What is otitis
media?
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. It is estimated that medical
costs and lost wages because of otitis media amount to $5 billion*
a year in the United States. Although otitis media is primarily
a disease of infants and young children, it can also affect
adults.
*Gates GA, Cost-effectiveness
Considerations in Otitis Media Treatment, Otolaryngol Head
Neck Surg, 114 (4), April 1996, 525-530.
How do we hear?
The ear consists of three major parts: the outer ear, the middle
ear and the inner ear. The outer ear includes the pinna—the
visible part of the ear—and 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.
Image of the inner ear
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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.
What causes otitis
media?
Otitis media usually results from a bacterial or viral infection
secondary to a cold, sore throat or other respiratory problem.
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.
What are the effects
of otitis media? 
Otitis media not only causes severe pain but may result in serious
complications if it is not treated. An untreated infection can
travel from the middle ear to the nearby parts of the head,
including the brain. Although the hearing loss caused by otitis
media is usually temporary, untreated otitis media may lead
to permanent hearing impairment. 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.
How can someone
tell if a child has otitis media?
Otitis media is often difficult to detect because most 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
- unresponsiveness
to quiet sounds or other signs of hearing difficulty such
as sitting too close to the television or being inattentive
Can anything be
done to prevent otitis media?
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.
How does a child's
physician diagnose otitis media?
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. The hearing
test is usually performed by an audiologist, a person who is
specially trained to measure hearing.
How is otitis
media treated?
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
so 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 infections
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 episodes of otitis
media in some children but not those who are under four years
of age. Research, however, has shown that removal of a child's
tonsils does not reduce occurrences of otitis media. Tonsillotomy
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 ear plugs while swimming or
bathing so that water does not enter the middle ear.
What research
is being done on otitis media?
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.
Where can I get
additional information?
May 1997
Updated April 1999
NIH Pub. No. 97-4216
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