Acute otitis media remains the most common diagnosis for which antibiotics are prescribed in children in the United States.^1,2 Approximately 15 million prescriptions are written every year, amounting to a cost conservatively estimated in the hundreds of millions of dollars.³

Acute otitis media (AOM) is defined in accordance with the Agency for Healthcare Research and Quality (AHRQ) as the acute onset of signs or symptoms of middle ear inflammation in association with a middle ear effusion.⁴ AOM is a disease predominately found in young children, with the incidence rate sharply declining after 5 years of age. The pathogens are primarily bacterial in origin, with viruses accounting for approximately one-third of cases.⁵

Historically in the United States, AOM always has been treated with antibiotics, even if the diagnosis is in question. Often, a child with a fever and runny nose whose tympanic membrane is only slightly erythematous will be diagnosed with AOM and given a 10-day course of antibiotics. Is this good medicine?

To answer that question, we must first understand the natural history of AOM. AOM is a disease that spontaneously resolves in more than 80% of children.^6-9 Appreciation of this fact is perhaps the single most important take-home point from this article, because the excessive and inappropriate use of antibiotics has been linked to a rising prevalence of penicillin-resistant S. pneumoniae.¹⁰ Penicillin-resistant S. pneumoniae increased from 27.5% in 1995 to 43.8% in 1997.¹¹

For more than 20 years, physicians in the Netherlands have used a treatment strategy for selected patients with AOM that withholds antibiotics for an initial observation period of 2-3 days. During that time, treatment is restricted to analgesics and antipyretics. Antibiotics are given only to those patients who fail to improve at the end of the observation period or whose condition worsens during the observation period.

As a result of this policy, the proportion of patients given antibiotics for AOM in the Netherlands is approximately 31%, and the resistance of S. pneumoniae remains below 1%.10,12

Although historically the standard approach to the treatment of AOM in the United States has been to administer antibiotics for all cases, concern about the rising rate of bacterial resistance and the success of the Dutch experience with initial observation have led to a shift in the treatment paradigm for AOM.

In the late 1990s, the New York State Department of Health assembled a committee of physicians whose purpose was to formulate a more judicious approach to the use of antibiotics for AOM. The culmination of the committee's work was a treatment strategy called the observation option, based closely on the Dutch model.

The observation option states that, because more than 80% of AOM cases resolve on their own, antibiotics can safely be withheld for up to 72 hours in selected children, during which time the child is observed and treatment is restricted to antipyretics and analgesics.

Antibiotics are started if the child fails to improve at the end of the initial observation period or worsens at any time during the observation period. The breakdown of which patients are appropriate for initial observation is shown in the accompanying table.¹³

As illustrated in the table, the target population for initial observation is the otherwise healthy child 2 years of age or older who has good follow-up and is not judged to be severely ill, as would be suggested by high fever or severe otalgia not easily ameliorated with analgesics. Children with any associated conditions that might reflect a relatively immunocompromised state would also be excluded from initial observation. Such conditions might include diabetes, Down syndrome, or any craniofacial abnormalities.

In the otherwise healthy child 6 months to 2 years, initial observation is an option if the diagnosis is uncertain, as would be suggested by clinical signs or symptoms of acute middle ear inflammation in the absence of high probability of concurrent middle ear effusion.

The observation option has been incorporated into the clinical practice guidelines of the American Academy of Pediatrics and the American Academy of Family Physicians. To date, the American College of Emergency Physicians has not made an endorsement.

The question should be asked: Is the observation option a workable treatment strategy in the unique environment of the emergency department?

There are two studies that have addressed this very question. Spiro et al. and Fischer et al. conducted two similar studies in which the parents of children who were diagnosed with AOM and were deemed appropriate candidates for initial observation were sent home with prescriptions for antibiotics. However, the parents were asked not to fill the prescription unless their child's condition worsened or failed to improve at the end of the observation period. Spiro et al. and Fischer et al. demonstrated that in 62% and 73% of cases, respectively, complete resolution of the symptoms of AOM took place without requiring antibiotics. In addition, both studies revealed a high degree of parental satisfaction with the treatment strategy, and no untoward effects occurred.

Given these two studies demonstrating effective and safe use of the observation option in the emergency department, together with more than 20 years of Dutch experience with observation, it would seem likely that there should be a decrease in the antibiotic prescribing rate for AOM in the emergency department. This does not appear to be the case. Fischer et al. demonstrated no decrease in antibiotic prescribing for children with AOM during the years 1996-2004.¹⁴

Why is this so? Several possible explanations exist.

First, it's possible that the word simply has not gotten out to enough emergency physicians in a sufficiently convincing way that AOM is a disease with a high rate of spontaneous resolution, and that antibiotics are not needed in the majority of the cases.

In addition, concerns about the lack of patient follow-up may make emergency physicians uncomfortable with the idea of not giving antibiotics.

Because ACEP has not yet endorsed the observation option, perhaps this lack of a "seal of approval," as it were, has given emergency physicians pause regarding the use of the observation option in clinical practice.

Furthermore, in the hectic and harried environment of the emergency department, diagnostic accuracy for AOM may be even harder to achieve than in other clinical environments, triggering antibiotic use when AOM may not even exist.

The goal of diagnostic accuracy in AOM is an elusive one, and diagnostic certainty is often hard to achieve.

Examining the tympanic membrane (TM) of an uncooperative child who is in pain is often challenging. As mentioned previously, the AHRQ definition of AOM requires the presence of a middle ear effusion. Except for a bulging TM, which correlates closely with the presence of middle ear fluid, it is difficult to determine the presence of middle ear fluid by visual inspection of the TM alone.

Pneumatic otoscopy is often rather glibly referred to in the literature as the diagnostic tool to be used to identify a middle ear effusion.

Pneumatic otoscopy, however, is not at all an easy test to perform. It requires a perfect seal of the external auditory canal, an unobstructed view of the TM and the insufflation of air into the ear canal of an already uncomfortable child, giving the examiner but a fleeting moment to assess whether or not the TM is moving normally.

Furthermore, the physician's assessment of TM mobility is completely subjective. Very few physicians use pneumatic otoscopy with any regularity.

Tympanometry is another diagnostic tool that identifies the presence of middle ear fluid. Although it provides accurate objective data, it too requires a perfect seal of the ear canal and an unobstructed view of the TM–two requirements that are not always easily achieved.

There is, however, yet another diagnostic modality available that, in this author's opinion, is the most practicable: acoustic reflectometry.

Acoustic reflectometry is a technology that determines the likelihood of a middle ear effusion based on the angle of a sound wave reflected off the TM. The test is performed quickly and painlessly using a portable handheld device approximately the size of an otoscope. In addition, the test does not require a perfect seal of the ear canal, nor does it require a completely unobstructed view of the TM.

Acoustic reflectometry correlates very closely with the results of tympanometry and is easier to perform.¹⁵

The device is so easy to use that a parental version is sold over the counter to enable parents to follow the course of their child's chronic ear effusions. When the device was introduced in 1997, it was described in Contemporary Pediatrics magazine as one of the best new products of the year. Acoustic reflectometry is also a reimbursable procedure, using the same code as tympanometry.

We hope this brief article will familiarize emergency physicians with the observation option for the treatment of AOM and re-acquaint them with the disease itself and the various nuances regarding its diagnosis.

A new treatment paradigm for AOM has the potential for dramatically decreasing antibiotic use for one of the most common pediatric diagnoses.

References

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