Acute otitis media is one of the most common pediatric conditions seen in primary care. In 1990 there were 12.8 million episodes of acute otitis media in children <5 yr old in the United States, with total estimated costs of $3.5 billion including $240 million spent on antibiotics (49). Despite the extensive clinical experience in the management of otitis media, there is no consensus regarding which antibiotics are most appropriate for initial or recurrent therapy, the optimal duration of therapy, or even whether antibiotics are of any significant benefit at all. The variation in management of otitis media is typified in an examination of the management of otitis media in nine countries in the mid-1980s (50). In this study, antibiotics were used over a wide range (31-98%) of episodes with similar variation in the types of antibiotics used and duration of therapy.
Because otitis media is a complication of URI, it has a peak incidence in the winter when colds are most likely to occur. Unlike sinusitis, which is more likely to affect adults, otitis media is predominantly a disease of younger children, with a peak incidence between 6 and 36 mo of age (51). Otitis media occurs with varying frequency in children. In a large population study, it was found that during the first 3 yr of life about a third of children never had otitis media, another third had one or two episodes, and the remaining third had three or more episodes.
Otitis media occurs more often in males, children in lower socioeconomic groups, and in certain ethnic groups such as Native Americans. Because of differences in the mechanics of the posterior pharynx and eustachian tube, children born with craniofa-cial congenital abnormalities such as cleft lip/palate and those with trisomy 21 also are more likely to have otitis media as a complication of a cold.
Otitis media arises from eustachian tube dysfunction that accompanies URIs or allergic rhinitis. Inflammation of the eustachian tube and middle ear results in tube occlusion and fluid accumulation in the middle ear space. Eustachian tube obstruction is more common in younger children because of less cartilage support of the tube, making collapse more likely. The Eustachian tube obstruction not only causes entrapment of existing fluid but also produces a negative pressure in the middle ear that results in additional fluid accumulation that characterizes serous otitis media. Contamination of this fluid with bacteria results in acute suppurative otitis media.
Suppurative otitis media is most often caused by the same organisms that result in sinusitis. Studies of middle ear aspirates suggest that Streptococcus pneumoniae is the most common bacterial cause of otitis media and is found in about 40% of effusions. H. influenzae accounts for approx another 20%. B. catarrhalis and Staphylococcus aureus each make up fewer than 10% of cases. In neonates, Gram-negative species also should be considered as potential etiologic agents.
Otitis media also may result from noninfectious obstruction of the eustachian tube. Allergic rhinitis, as noted previously, is one such mechanism. Other causes include enlargement of the adenoids and posterior pharyngeal tumors.
The treatment of acute suppurative otitis media remains controversial. As indicated previously, there is a great deal of regional variability in the treatment methods used for this condition. However, a recent meta-analysis of six studies that investigated antibiotic therapy in children found no statistically significant benefits of antibiotics in children under the age of 2 (52). However, there were several methodologic problems with many of these study that may limit the validity of these findings.
Other studies point out that otitis media may be overdiagnosed, especially in younger children, which complicates the evaluation of treatment effectiveness. Physicians' certainty about the diagnosis of otitis media was dependent on the patient's age. In a multinational study, it was found that physicians were certain of the diagnosis in only 58% of children under the age of 1 yr (50). This increased to 66% in those between 1 yr and 30 mo of age and up to 73% in those over 30 mo of age. In this group, regardless of age, antibiotic therapy did not appear to influence outcomes. However, as physician uncertainty about whether the child had suppurative otitis media was fairly high, it is likely that a large number of children without otitis media were included in the outcome measurement.
If antibiotics are selected for the management of acute suppurative otitis media, selection of an agent should provide coverage for the two most common organisms, S. pneumoniae and H. influenzae. Second, the duration of antibiotic treatment should be as short as possible to minimize the development of antibiotic resistance. In a metaanalysis of trials that compared short-duration antibiotic therapy with the traditional 10-d course, no benefit was found of using longer courses of treatment (53). A 5-d course of antibiotics should be sufficient for treatment.
In addition to short-course therapy, a single intramuscular dose therapy of ceftriaxone has been shown to have benefit equal to that of longer courses of amoxicillin (54), cefaclor (55), or trimethoprim-sulfamethoxasole (56) for the treatment of acute suppurative otitis media. Where antibiotic resistance to S. pneumoniae is high or where patient compliance is an issue, ceftriaxone may be a viable alternative.
The primary concern in the treatment of otitis media is a primary treatment failure, i.e. persistent illness or a early recurrence of disease following initial therapy of a new otitis episode (57). While a meta-analysis of 33 randomized trials supports initial antibiotic use (94% primary treatment success vs. 81% with placebo) (58), there were no significant differences in failure rates when comparing "standard" or first-line (penicillin, amoxicillin/ampicillin, erythromycin, and sulfamethoxazole) and "extended-spectrum" or second-line antibiotics or with duration of therapy. The only factor that appears to be consistently linked to a higher likelihood of a primary treatment failure is a child's age (59,60), with children younger than 2 yr of age of age having treatment failures in 26-37.5% of cases. For older children, treatment failures occur in 2-19% of episodes (59,60).
Also of concern is how to manage a new case of otitis media when a previous treatment failure has occurred. In a study that examined failure rates in new infections for children who had a previous treatment failure, there was no benefit of starting therapy with an extended-spectrum agent compared to "first-line" drugs. Thus it appears that in a case of previous treatment failure, new cases should be managed with narrow-spectrum agents such as amoxicillin or trimethoprim-sulfamethoxasole (61).
The use of second-line antibiotics when a first line agent will suffice creates two problems. First, in most cases the use of broad-spectrum drugs adds significant expense to therapy. Others have reported that use of second line agents compared to amoxicillin or trimethoprim-sulfamethoxasole adds 16% to the overall cost of the episode (57). Since the results of this study show comparable failure rates for first- and second-line antibiotics, there appears to be no justification for this additional cost.
Second, the injudicious use of broad-spectrum antibiotics may increase the potential for future development of antibiotic resistance. The overuse of antibiotics has been proposed as one reason for the observed growth in antibiotic resistance reported in common childhood organisms such as Streptococcus pneumoniae. Otitis media is a condition in which antibiotics are frequently prescribed for children and where broad-spectrum antibiotics may be used unnecessarily. Limiting the use of broad-spectrum drugs to situations in which they are beneficial (i.e., managing the resistant case of otitis) may help reduce further development of drug resistance in children.
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