Otitis media
- Otitis media, or inflammation of the middle ear, is defined
- by the presence of fluid in the
middle ear
- accompanied by signs or symptoms of acute illness.
- The peak incidence occurs in the first 3 years of life.
- The disease is less
common in the school-aged child, adolescents, and adults but the bacteriology and therapy are similar to those in children.
- In addition, adults suffer from the sequelae of otitis media of childhood:
- hearing loss
- cholesteatoma
- adhesive otitis media
- chronic perforation of the tympanic membrane
Predisposing factors
- The vast majority of children
have no obvious defect responsible for severe and recurrent otitis media
- Otitis media is most common
in the younger age groups.
- The eustachian tube wall
lacks stiffness in infants and young children.
- Older individuals have eustachian tubes
with stiffer walls which are less likely to collapse.
- In addition, as the
eustachian tube grows with an individual, a small amount of swelling due to
an upper respiratory infection is less likely to occlude the tube or cause
significant tube dysfunction.
- A small
number have
- Eustachian tube dysfunction include anatomic
abnormalities (Down's syndrome,cleft palate, cleft uvula, submucous cleft)
- alteration of
normal physiologic defenses (patulous eustachian tube)
- congenital or acquired
immunologic deficiencies.
- Breast-feeding for 3 or more months is
associated with a decreased risk of
acute otitis media in the first year of life.
- Race and ethnicity provide additional data
suggesting a genetic basis for recurrent middle ear infections; Native Americans, Alaskan
and Canadian Eskimos, and Australian aborigines have an extraordinary incidence and
severity of otitis media.
- The introduction of infants into large day care
groups increases the incidence of respiratory infections, including otitis media.
- Passive smoking documented by a biochemical marker, the serum nicotine
level, increased the incidence of new episodes of otitis media with effusion and the
duration of effusion.
Classification
-
Episodes of otitis media should be classified as acute otitis media (AOM) or otitis media with effusion
(OME).
Etiologic agents
The most common causes of otitis media are
- Streptococcus pneumoniae
(40 %)
- Hemophilus influenzae (30%)
- Moraxella catarrhalis (15%)
Group
A streptococcus and Staphylococcus aureus are rare causes of otitis media
Viruses
-
Virologic and epidemiologic data suggest that viral infection is frequently associated with
acute otitis media.
- Respiratory syncytial virus, influenza virus,
enteroviruses, and rhinoviruses were the most common viruses found in middle ear fluids.
-
Many patients with virus in middle ear fluid have a mixed viral-bacterial infection.
Mycoplasma, Chlamydia, and Unusual Organisms rarely.
Pathogenesis
-
The middle ear is part of a continuous system that includes the nares,
nasopharynx, and
eustachian tube medially and anteriorly, and the mastoid air cells posteriorly.
- These
structures are lined with a respiratory epithelium that contains ciliated cells,
mucus-secreting goblet cells, and cells capable of secreting local
immunoglobulins.
- The eustachian tube is the structure which plays a major role in the
development of acute otitis media.
- The eustachian tube has at least three physiologic
functions with respect to the middle ear:
- protection of the ear from nasopharyngeal
secretions
- drainage into the nasopharynx of secretions produced within the middle
ear
- ventilation of the middle ear to equilibrate air pressure with that in the external ear
canal
- When one or more of these functions is compromised, the results may be the
development of fluid and infection in the middle ear.
- Viral or allergy
- Viral upper respiratory infection
or allergy causes inflammation and edema in the eustachian tube, impairing
its normal functions.
- When ventilation of the middle ear is lost, oxygen is
absorbed from the air in the middle ear and negative pressure
results.
- This negative pressure draws bacteria into the middle ear.
Clinical manifestations
- Symptoms
- ear pain
- ear drainage
- hearing loss
- nonspecific, such as fever, lethargy, or irritability
-
Vertigo, nystagmus, and tinnitus may occur
Physical findings
- Redness of the tympanic membrane is an
early sign of otitis media, but erythema alone is not diagnostic of middle ear infection
since it may be caused by inflammation of the mucosa throughout the upper respiratory
tract.
-
The presence of fluid in the middle ear is determined by the use of pneumatic otoscopy, a
technique that permits an assessment of the mobility of the tympanic membrane.
-
Fluid persists in the middle ear for prolonged periods after the onset of acute otitis media
even though symptoms usually resolve within a few days after the initiation of
antimicrobial therapy.
- The
motion of the tympanic membrane is proportional to the pressure applied by gently
squeezing and then releasing the rubber bulb attached to the head of the otoscope.
- Normal
mobility is apparent when positive pressure is applied and the tympanic membrane moves
rapidly inward; with release of the bulb and the resulting negative pressure, the membrane
moves outward.
- Fluid or high negative pressure in the middle ear dampens the mobility of
the tympanic membrane.
- Tympanometry uses an
electroacoustic impedance bridge to record compliance of the tympanic membrane and
middle ear pressure.
- This technique presents objective evidence of the status of the middle
ear and the presence or absence of fluid.
- hearing loss of variable severity.
- lower in tests of speech, language, and cognitive abilities than do their disease-free
peers.
Complications and long-term consequences .
- Mastoiditis was a very common infection in the pre-antibiotic era,
and results from spread of infection from the middle ear to the mastoid air
cells of the temporal bone
- A bulging tympanic membrane will occasionally
spontaneously perforate, with purulent discharge seen from the ear canal.
-
These perforations spontaneously heal and cause no long-term damage.
-
Persistent middle ear effusion may follow an acute otitis media, and result
in hearing loss and language delay in young children. Intracranial
infections such as meningitis can occasionally occur.
- Chronic otitis media
may result in formation of a cholesteatoma, an overgrowth of squamous
epithelium in the middle ear which must be removed by resection to restore
proper hearing.
Diagnosis
The only way to determine the specific pathogen in the middle ear is
to perform tympanocentesis . It is not commonly performed, and antibiotic therapy is generally
used empirically. Tympanocentesis should be considered in selected patients:
-
the patient who is critically ill at the onset
- for patients who fail to respond to therapy, in 48 to 72 hours and is
toxic
- for neonates in whom
the bacteria causing, otitis media may be different (group B streptococcus
and gram-negatives)
- for immunocompromised patients
Therapy
- Amoxicillin remains the drug of choice for the treatment of acute
otitis media.
- It will cover non-penicillin resistant Streptococcus
pneumoniae, and beta-lactamase negative strains of Hemophilus influenzae and
Moraxella catarrhalis.
-
With appropriate antimicrobial therapy, most children with acute otitis media are
significantly improved within 48 to 72 hours. If there is no improvement, the patient should
be reexamined.
- Penicillin resistant Streptococcus pneumoniae.
- If a patient fails to respond, he may require treatment with a second-line
agent for presumed beta-lactamase positive organisms.
- In these
patients, tympanocentesis to establish a bacteriologic diagnosis is helpful.
-
Optimal treatment of penicillin-resistant S. pneumoniae otitis media is
currently unclear, but may include drugs such as IM ceftriaxone or oral
clindamycin.
- Antimicrobial agents are indicated for treatment of
AOM
-
Acute otitis media can be treated with a 5- to 7-day course of antimicrobial agents in certain children 2 years of age or older.
- Younger children and children with underlying medical conditions, craniofacial abnormalities, chronic or recurrent
otitis media, or perforation of the tympanic membrane, should be treated with a standard 10-day course.
- Persistent middle ear effusion (OME) for 2 to 3 months after therapy for AOMis expected and does not require
retreatment.
Antimicrobial agents are not indicated for initial treatment of
OME; treatment may be indicated if effusions persist for 3 months or more.
Decongestants, Antihistamines, and Corticosteroids.: no significant evidence of efficacy of any of these
preparations.
Chronic Otitis Media
-
The term chronic otitis media includes recurrent episodes of acute infection and a
prolonged duration of middle ear effusion usually resulting from a previous episode of
acute infection.
- For the prevention of recurrent episodes of acute otitis media,
management includes the consideration of
- chemoprophylaxis (the use of antimicrobial
agents).
- A reduction of
episodes of acute febrile illnesses due to otitis media occurred.
- Children should be considered for prophylaxis if they
have had two episodes of acute otitis media in the first 6 months of life or, in older
children, three episodes in 6 months or four episodes in 1 year.
- Amoxicillin, 20 mg/kg, or
sulfisoxazole, 50 mg/kg, may be administered once a day.
- The physician who chooses to use chemoprophylaxis to prevent
acute recurrent disease must examine the patient at approximately 1-month intervals for
middle ear effusion.
- immunoprophylaxis (the use of vaccines or
immunoglobulin)
-
Pneumococcal vaccines have been evaluated for the prevention of recurrences of acute
otitis media in children.
- As in previous studies, children younger than 2 years
had unsatisfactory responses to single-dose regimens.
- The vaccine reduced the number of
episodes of acute otitis media due to types of S. pneumoniae present in the vaccine, but
the reduction was not sufficient to alter the experience of the children with middle ear
infections.
- The basis for failure of the vaccine was due to the poor immunologic response
to the polysaccharide antigens in the young infants enrolled in the trials.
- The data
suggested that the vaccine was likely to be more effective in children older than 2 years.
- Vaccines composed of pneumococcal capsular polysaccharides conjugated to proteins
increased immunogenicity in young infants and are currently undergoing clinical
evaluation.
- Because of the importance of respiratory viruses in the pathogenesis of acute otitis
media, viral vaccines could be of preventive value.
- Influenza virus vaccine has been
documented to decrease the incidence of acute otitis media in children in day care in
Finland and North Carolina.
- For the
management of persistent middle ear effusions, three surgical methods are considered:
-
myringotomy
- Myringotomy,
or incision of the tympanic membrane, is a method of draining middle ear fluid.
- Myringotomy offers
quick pain relief when a patient is in severe pain from otitis media.
- Today, the use of myringotomy is limited to the relief of
intractable ear pain, hastening resolution of mastoid infection, and drainage of persistent
middle ear effusion that is unresponsive to medical therapy.
- adenoidectomy
- Enlarged adenoids may obstruct the orifice of the eustachian tube in the posterior portion
of the nasopharynx and interfere with adequate ventilation and drainage of the middle ear.
-
Tympanostomy tubes resemble small collar buttons.
- They are placed through an incision in
the tympanic membrane to provide drainage of fluid and ventilation of the middle ear.
-
The criteria for the placement of tubes include persistent middle ear effusions
unresponsive to adequate medical treatment over a period of 3 months and persistent
negative pressure.
- Hearing improves dramatically after placement of the ventilating tubes.
-
The tubes have also been of value in patients who have difficulty maintaining ambient
pressure in the middle ear such as would occur due to barotrauma in airline personnel.
-
The liabilities of the placement of tubes include those of anesthesia associated with the
procedure, persistent perforation, scarring of the tympanic membrane, the development of
cholesteatoma, and otitis media caused by swimming with ventilating tubes in place, but
these occur infrequently.
Prevention
- Recurrences may be prevented in patients with recurrent otitis media
by either placement of tympanostomy tubes (which provide continuous
ventilation of the middle ear by means of a plastic ventilation tube which
has one end in the middle ear and the other end in the external ear canal)
or prophylactic antibiotic therapy.
-
Both pneumococcal vaccine and influenza vaccine have been shown to be
effective in reducing the number of episodes of otitis media in otitis-prone
patients.
- Unfortunately, currently available pneumococcal vaccine is not
effective in children less than 2 years of age, the group at greatest risk
of developing recurrent otitis media.
-
Otitis media due to H. influenzae is associated with nontypable strains in the vast
majority of patients.
- Antimicrobial prophylaxis should be reserved for control of recurrent
AOM, defined as 3 or more distinct and well-documented episodes per 6 months or 4 or more episodes per 12 months.