ACUTE OTITIS MEDIA results when pathogens from the nasopharynx are
introduced into the inflammatory fluid collected in the middle ear—e.g., by
nose blowing during a URI. The proliferation of these pathogens in this space
leads to the development of the typical signs and symptoms of acute middle-ear
infection. The diagnosis of acute otitis media requires the demonstration of
fluid in the middle ear (with tympanic membrane immobility) and the
accompanying signs or symptoms of local or systemic illness.
ETIOLOGY Acute otitis media typically follows a viral URI. The causative viruses
(most commonly RSV, influenza virus, rhinovirus, and enterovirus) can
themselves cause subsequent acute otitis media; more often, they predispose the
patient to bacterial otitis media. Studies using tympanocentesis have
consistently found S. pneumoniae to be the most important bacterial cause, isolated in up to 35% of
cases. H. influenzae (nontypable
strains) and M. catarrhalis are also common bacterial causes of acute otitis media. Viruses,
such as those mentioned above, have been recovered either alone or with
bacteria in 17 to 40% of cases.
MANIFESTATIONS Fluid in the middle ear is
typically demonstrated or confirmed with pneumatic otoscopy. In the absence of
fluid, the tympanic membrane moves visibly with the application of positive and
negative pressure, but this movement is dampened when fluid is present. With
bacterial infection, the tympanic membrane can also be erythematous, bulging,
or retracted and occasionally can spontaneously perforate. The signs and
symptoms accompanying infection can be local or systemic, including otalgia,
otorrhea, diminished hearing, fever, or irritability. Erythema of the tympanic
membrane is often evident but is nonspecific as it is frequently seen in
association with inflammation of the upper respiratory mucosa (e.g., during
examination of young children). Other signs and symptoms occasionally reported include
vertigo, nystagmus, and tinnitus.
TREATMENT There has been considerable debate on the usefulness of
antibiotics for the treatment of acute otitis media. Although most cases
resolve clinically 1 week after the onset of illness, there appears to be some
benefit to the use of antibiotics, with a higher proportion of treated than of untreated
patients free of illness 3 to 5days after diagnosis. The difficulty of
predicting which patients will benefit from antibiotic therapy
has led to different approaches. In the Netherlands, for instance,
physicians typically manage acute otitis media with initial observation and aggressive
pain management with anti-inflammatory therapy, reserving antibiotics for
high-risk patients, patients with complicated disease, or patients who do not
improve after 48 to 72 h. In contrast, many experts in the United States
continue to recommend antibiotic therapy for children <2 years old in light of the
higher frequency of secondary complications in this young and functionally
immunocompromised population.
Given that most
studies of the etiologic agents of acute otitis media consistently document
similar pathogen profiles, therapy is generally empirical except in those few
cases where tympanocentesis is warranted—e.g., cases in newborns, cases
refractory to therapy, or cases in patients who are severely ill or who have an
immune deficiency. Despite resistance to penicillin and amoxicillin in roughly
one-quarter of S. pneumoniae isolates, one-third of H. influenzae isolates, and nearly all M. catarrhalis isolates, outcome studies continue to find that amoxicillin is as
successful as any other agent, and it remains the drug of first choice in
recommendations from the Centers for Disease Control and Prevention (CDC; Table
27-1). Therapy is typically administered for 5to 7 days for uncomplicated acute
otitis media; longer courses (e.g., 10 days) have traditionally been
prescribed, but evidence suggests that this duration should be reserved for
complicated cases or for children <2 years old, in whom short-course therapy may be inadequate.
A switch in regimen is recommended if there is no clinical
improvement by the third day of therapy, given the possibility of infection with
a -lactamase-producing strain of H. influenzae or M. catarrhalis or with a strain of penicillin-resistant S. pneumoniae. Decongestants and
antihistamines are frequently used as adjunctive therapy to reduce congestion
and relieve obstruction of the Eustachian tube, but clinical trials have
yielded no significant evidence of benefit with either class of agents.
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