a SLACK Incorporated newspaper
February 1998
NEW YORK CITY - Because of antimicrobial resistance, there has been much discussion about whether children with acute otitis media (AOM) should be treated. Jerome O. Klein, MD, came down on the side of treatment at the 10th Annual Infectious Diseases in Children Symposium.
"Antibiotics do work for AOM," he said. "They resolve the acute signs within 48 to 72 hours. They decrease the time the child spends with middle ear fluid, and they decrease the complication rate."
If physicians are worried about resistance, they should use better techniques to diagnose AOM to confirm the condition; otitis media with effusion does not require antimicrobial therapy. "I think we can do better with diagnosis," said Klein, professor of pediatrics at Boston University School of Medicine.
"You should have all the equipment that is available to you. It can help you hone those diagnostic skills because it confirms or denies the diagnosis. I think physicians should be assisted by the instrumentation that is available today," added Klein, of Boston Medical Center.
The issue has come to the forefront because antibiotic overuse is causing selective pressure by increasing the proportion of antibiotic-resistant strains. But Klein does not think that treating AOM appropriately is overusing antibiotics. Instead, physicians should help educate parents so they know when antibiotics are appropriate, and they should not yield to pressure to inappropriately prescribe antibiotics.
There are arguments against immediate treatment. One-third of cases are not caused by a bacterial pathogen; they are either a viral or allergic etiology and will not respond to antibiotics, and about 20% will clear spontaneously.
In Europe, there are children who are not treated for AOM because of this spontaneous resolution. Children are handled differently depending on their age; and 2 years old is the cut-off point. "I think that is very wise," Klein said. "The disease is different in children under 2 years. It is probably the most significant risk feature for the need for treatment.
"Over 2 years, they provide symptomatic treatment for the first three days then re-evaluate. If they are still symptomatic, they may continue observation or initiate antibiotics. For children under 2 years old, I think they pull the trigger more quickly. They may observe for a day and they re-evaluate or perhaps they begin treatment immediately. And they are quick to turn to their otorhinolaryngologic colleagues," Klein explained.
Klein said there are two problems with this method. First, no one can tell by the initial examination which children will clear spontaneously and who won't. Second, the European children suffer occasional complications of non-treated AOM, namely mastoiditis. "One has to ask the question about whether the trade-off of complications is worth the risk," Klein said.
However, these countries do experience lower rates of resistant organisms than the United States. Here, 20% to 40% of pneumococcal strains are intermediate or fully resistant. In the Netherlands, where antimicrobials are not first-line treatment for AOM, resistance is less than 1%. In Asia, where there is a higher rate of use of antimicrobials, 89% of pneumococcal strains are resistant; half of which have a high level of resistance.
"The pneumococcal resistant story is one of increments," he said. Organisms are classified as either susceptible, intermediately resistant or highly resistant. Klein said that highly resistant organisms cause the most concern, and these are low even in the United States.
Susceptible strains have MICs of less than 0.1 mg; intermediate strains are 0.1 mg to 1 mg and high resistance is 2 mg or more. "It is the high resistance group with MICs of 2 mg or more that is the critical area in terms of clinical failure or efficacy," he said.
"To put this into perspective, usual doses of amoxicillin or amoxicillin-clavulanate [Augmentin, SmithKline Beecham] can achieve concentrations in the middle ear of 2 mg to 4 mg and the newer dosage formulations give even higher concentrations. So, we ought to be able to cover most of the intermediately resistant strains."
With a 10 mg dose of amoxicillin, one can achieve in the serum 5 mg to 10 mg; about 40% diffuses into the middle ear, so there is good diffusion into the inflamed middle ear - in excess to 2 mg. "The usual dose of amoxicillin ought to be able to take care of the intermediately resistant strains; perhaps there might be some difficulties with the highly resistant strains. But even some of those should be covered," he said.
There also appears to be a difference by source. Nasopharyngeal isolates and middle ear isolates have higher incidence than blood or spinal fluid. This may be due to antimicrobial use. "The patient who comes in with an invasive event - meningitis - may not have had a prior antimicrobial agent, where the child who had a tympanocentesis is likely to either be on a drug or to have had a drug previously."
Children appear to have more resistant strains than adults. Risk factors are previous antibiotic use, prior hospitalization and day care attendance. Day care attendance is an exposure issue. If one child has a resistant strain, it spreads quickly to the others.
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"I would suggest that amoxicillin is still the drug of choice," he said. If the child has failed amoxicillin, use higher dose amoxicillin-clavulanate, cefpodoxime (Vantin, Pharmacia & Upjohn) cefuroxime (Ceftin, Glaxo Wellcome), ceprozil (Cefzil, Bristol-Myers Squibb) or ceftriaxone (Rocephin, Roche Laboratories). Ceftriaxone given as a one-time injection is appropriate in some children. At Klein's urban institution, many poor and homeless children are treated. Since these children are unlikely to return for follow-up or have difficulty following a treatment regimen, an injection may be most appropriate.
Some children, usually treatment failures or those with repeated cases of OM, are placed on long-term prophylaxis, and Klein discussed that briefly. "If you give a modified dosing schedule for a prolonged period, you will decrease colonization, which will be effective in decreasing occurrences, but there is a problem with resistance; giving a modified dose of antibiotic for a prolonged period is an excellent way of creating drug resistance," he explained.
As in most decisions doctors make, they must weigh the benefit and the risk.
For more information:
- Klein JO. Are antimicrobial agents necessary for all children with acute otitis media? Presented at the 10th Annual Infectious Diseases in Children Symposium. Nov. 22-23. New York.
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