Update on Otitis Media

In both abstract plenary sessions and topic sessions, there were several investigations of otitis media (OM) that pediatricians would find interesting. Since practice patterns suggest that approximately 60% of the antibiotics prescribed for children are to treat OM,^[7] thinking about how this common pediatric clinical problem is diagnosed and treated is always worthwhile.

Bullous Myringitis

In an abstract presentation, David McCormick, MD,^[8] of the University of Texas Medical Branch, Galveston, reported the results of a study that attempted to determine whether bullous myringitis was a "severe" form of OM. This case-control study identified patients aged 6 months to 12 years with signs and symptoms of acute OM. The investigation excluded OM patients with effusion (OME), attempting to exclude children with sterile effusions who did not have acute infection. Children were also excluded if they had myringotomy tubes or craniofacial anomalies.

Parents reported a symptom score for their children, and the degree of middle ear disease was graded using video otoscopy and trained scorers (all pediatricians). A tympanic membrane with erythema, bulging, and a bulla (bullous myringitis) was considered the most severe classification. Children with erythema, opacity, and bulging without bulla comprised the classification just below the bullae group in severity. In the cohort, 518 subjects had acute OM, and 41 (8%) had bullous myringitis. The 41 cases were then matched to control subjects based on ethnicity, age, and gender. There were no differences between cases and controls for number of hours spent in daycare, duration of breast-feeding, tobacco smoke exposure, and prior OM history. Although the children with bullous myringitis had temperatures that were similar to those of children without this diagnosis, they did have significantly higher symptom scores as assessed by parents.

The authors concluded that bullous myringitis is a more severe form of OM. Their take-home message is that parents of children with bullous myringitis may be less likely to consider "watchful waiting" compared with parents of children with OM and no bullae.

Choice of Antibiotics for Otitis Media

In an invited platform session, Dr. McCormick also gave an overview of current issues in diagnosing and treating OM.^[9] He focused on whether antibiotic treatment is necessary for mild cases of OM, and on the changing flora involved in OM since the advent of conjugate vaccines against H influenzae type b and S pneumoniae.

The presentation began with a review of unpublished data from a study McCormick and colleagues are completing with funding from the Agency for Healthcare Research and Quality. The ongoing investigation is evaluating outcomes in children with nonsevere acute OM (n = 129 so far), and half of the participants are being treated with placebo instead of amoxicillin.^[9] The goal is to determine the differences in short-term outcomes for children treated vs not treated with antibiotics for nonsevere acute OM.

The authors define "failure" as need for change in antibiotics within a 10-day period. Investigators were blinded as to patient medication, so any treatment change was approached as if it were an antibiotic failure. To date, groups have been very similar with regard to the occurrence of failure rates, with 30% of the placebo group and 26% of the treatment group experiencing "failure." However, the groups showed differences in the timing of experiencing failure. The placebo group experienced failure mostly during the first 10 days after diagnoses, compared with 14 to 28 days in the treated group.

On the basis of these data, McCormick suggested that many children with nonsevere acute OM (no bullae on the tympanic membrane) could be watched and not treated initially with antibiotics. He contends that children who "fail" the placebo approach will do so within 10 days of the index visit, so any worsening of symptoms in the week after the index visit would suggest the need to treat with antibiotics.

Changing Pathogens in OM

Data from 2 other investigations that demonstrated how the use of newer vaccines is changing the "face" of OM were also reviewed by Dr. McCormick. Published data from Fireman and coauthors^[10] revealed that the pneumococcal conjugate vaccine produced a 7% reduction in episodes of OM (defined in that study as including acute OM and OME) and a 24% reduction in myringotomy tube placement in a large Kaiser-Permanente cohort. McCormick believes that the rate of decrease in acute OM in the future will actually be greater than 7%, since the percentage identified in that study included children with OME. He suggested that in the short term we will see improvement in the burden of OM, especially with regard to children needing myringotomy tube placement.

Finally, Dr. McCormick reviewed data on the changing face of the organisms involved in OM, presented earlier in the PAS 2003 meeting by Stan Block, MD.^[11] Dr. Block reported bacterial culture isolate results obtained by office myringotomy from 2 cohorts: (1) isolates collected before the use of pneumococcal conjugate vaccine, and (2) isolates collected after the pneumococcal vaccine became available.

In the pre-pneumococcal conjugate vaccine cohort, approximately 30% of patients with acute OM had non-typeable H influenzae isolated from the middle ear. That rate has now increased to 52%. In addition, nonvaccine strains of pneumococcus have almost doubled in the same time period, and now comprise 3.5% of all bacteria isolated. The good news is that the pneumoccoccal isolates carrying most pneumococcal resistance are included in the 7-valent vaccine and comprise a declining proportion of isolates.

There were several take-home messages from Dr. McCormick's presentation:

Many children will still do well without treatment for acute OM, and those who experience treatment failures will do so within 10 days of diagnosis.
Pneumococcal conjugate vaccine will have a significant impact on OM, with a large reduction in the number of children who will require myringotomy tubes.
A short-term decline in the problems of pneumococcal resistance may also be seen since most of the resistant organisms are included in the current vaccine and appear to be declining in frequency. More information on this topic is provided in a recently published article by Whitney.^[12]
H influenzae is increasing as a pathogen in acute OM, as are nonvaccine pneumococcal strains. This change in flora may be helpful in the short term, but may also lead to the need to adjust or revise pneumococcal vaccine components.