Otitis media with effusion (OME) refers to a painless collection of middle ear fluid without signs of acute infection. Symptoms might include hearing loss, behavioral changes such as inattentiveness, and, in the older child, occasional complaints of a "blocked up" or "plugged" ear. Although OME can arise without preceding infection, most cases evolve from acute otitis media (AOM). There is a continuum with overlap between these two conditions. Because middle ear effusion (MEE) is present in both AOM and OME, the clinical challenge is to differentiate the two. This distinction is often difficult and may not always be possible with a high degree of certainty.1-2 In this article, we share our clinical observations regarding, experience with, and approach to the problem of OME from the point of view of a practicing pediatrician and a practicing otolaryngologist whose patients are primarily from middle-class families.
The natural history of AOM and OME has been comprehensively reviewed.3 Approximately 65% of children with untreated AOM will still have MEE after 2 weeks, 40% after 1 month, and 25% after 3 months. The resolution rate for newly detected cases of OME of unknown cause is also favorable. However, spontaneous resolution is less likely for children with documented bilateral OME lasting 3 months or longer, as 75% will still have MEE at 6 months and 70% at 2 years.3
The etiology of OME is multifactorial, and includes infection, eustachian tube dysfunction, and allergy. The three most commonly encountered bacterial species in OME are the same as those in AOM (ie, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis), with the relative frequency of H. influenzae being greater in OME than in AOM.4 These major pathogens have been found in OME by culture in 29% of cases, and have been suggested by polymerase chain reaction technique in an additional 48%. 5 In another polymerase chain reaction study, 85% of OME was positive for Alloiococcus otitidis, a Micrococcus-tike staphylococcus.6 The significance of these bacterial findings remains uncertain, as an analysis of 13 randomized, controlled trials showed that a course of antibiotics was likely to help in the short-term resolution of OME in only 15% of cases, so 7 patients would have to be treated to resolve OME in a single child.7 OME may also be caused or prolonged by cytokine-mediated inflammation due to the presence of cell wall breakdown products from bacteria such as H. influenzaci
In some cases there seems to have been no antecedent infection, and dysfunction of the eustachian tube alone may be the culprit. In infants, mis dysfunction may be related to a shorter, straighter, and more compliant eustachian tube.8 In children older than 4 years, eustachian tube dysfunction is often due to chronic adenoiditis.9 Underlying craniofacial anomalies (eg, cleft palate and Down syndrome) adversely affect eustachian tube function. Heredity is also a significant factor, as has recently been shown in a study of twins and triplets.10
The incidence and importance of allergy in OME is controversial. In children younger than 3 years, and especially in those younger man 2 years, food allergy may at times be a factor.11 Inhalant allergies may become more important in older children.11 Some have suggested mat allergy plays a role in as many as 35% to 40% of cases of OME.12 That percentage would seem high for a pediatrie practice, but perhaps is true for older children in a referral population.
POTENTIAL CONSEQUENCES OF OME
The primary concern about asymptomatic OME is its possible effect on speech and language development. All practitioners have heard anecdotal stories from parents about how the child immediately becomes more verbal and responsive after tympanostomy tube insertion. After reviewing all available literature, a panel of experts had difficulty making strong conclusions about the negative impact of the conductive hearing loss associated with OME on speech and language development.13 An analysis of more recent studies does suggest that otitis media negatively impacts language development, especially expressive language, in preschool children.14 Whether short-term hearing loss from OME can lead to more long-term speech and hearing problems is currently being investigated.15
The concern about the temporary hearing loss from OME leading to speech delay applies mainly to infants. In older children, the concern with the hearing loss is its effect on school performance and social interactions. Rosenfeld et al.16 demonstrated that word recognition scores in children with OME deteriorated in the presence of background noise. Interestingly, all of those children had pure-tone audiometry within normal range (< 25 dB). If these findings are confirmed, the implications for such a child in a noisy classroom are significant.
The consequences of chronic OME are not limited to hearing loss and speech delay. The lingering MEE provides an excellent culture medium for recurrent AOM. In our experience, the most common scenario for placement of tympanostomy tubes is recurrent AOM with persisting OME between episodes. Chronic OME alone is a much less common reason for placement of tympanostomy tubes and is usually limited to children older than 3 years. In this older population, the other worrisome process associated with OME is tympanic membrane (TM) atelectasis. This severe retraction is of special concern because it can lead to permanent eardrum damage, ossicular discontinuity, or even cholesteatoma formation. Finally, chronic OME can result in balance and motor skill problems,17 as well as behavioral changes such as ill temper and inattention.18
In pediatrie practice, most cases of OME are diagnosed when patients present for a follow-up visit after recent AOM, or prior to that when there are signs of incomplete resolution of the previous AOM infection, or of a new bout of AOM. The latter is usually associated with continuing or recent-onset rhinorrhea. At other times, the diagnosis of OME is made during a well-child visit. In older children, the visit may have been scheduled because of questionable hearing loss or a failed hearing test at school. Hearing loss may be subtle in children,19 and, in our experience, is most commonly manifested by a need for increased television volume or what appears to be ignoring behavior.
Figure 1 . Pneumatic otoscope with special lens head (Model 20206, Welch Allyn, Inc., Skaneateles Falls, NY).
The diagnosis of OME may require more complete visualization of the TM than AOM, as even partial visualization may at times be sufficient for the latter diagnosis to be made. A diagnostic otoscope head with a halogen lamp and a rubber bulb insufflator is essential. We prefer the round otoscope head as opposed to the square head because it gives a better seal for pneumatic otoscopy. With an auxiliary lens (Fig. 1 ), it can also be used as an operative otoscope to remove cerumen. A OO ear curette can be used to remove wax under direct vision through a speculum as small as 3 mm, die size most commonly needed in younger children. We find the disposable speculae for the standard round head otoscopes to be inexpensive and adequate for routine otoscopy.
The diagnostic techniques for examining for otitis media in children have been excellently described by Kaleida.20 The first step otoscopicalIy is to determine whether MEE is present. MEE is relatively easy to identify if an air-fluid level is present or if the color of the fluid is distinct (eg, yellow). Visualizing MEE is more difficult when the fluid fills the middle ear space and is more clear in color. In this situation, assessing mobility of the TM is especially helpful.
If MEE is present, does it represent AOM or OME? The two most helpful otoscopie findings are the translucency and die position of the TM. Logically, a translucent TM would be present only if significant inflammation is absent. As such, this translucency is compatible with a normal middle ear and even certain cases of OME, but not with AOM unless it is early. A nontranslucent (ie, opaque, dull, or thickened) TM suggests that inflammation is present and is consistent with AOM, OME, or myringitis.
Figure 2. A translucent tympanic membrane with an air-fluid level almost always represents otitis media with effusion.
To differentiate whether an opaque TM with decreased mobility is AOM or OME, its position is crucial. A TM that is bulging outward is the otoscopie finding mat best correlates with the presence of pathogenic bacteria.21,22 The single most important landmark in determining the position of the TM is the prominence (or lack thereof) of the short, or lateral, process of the malleus. As far back as 1931, Brennemann wrote that "the practical measure of bulging is obliteration of the short process, the diagnostic role of which cannot be overemphasized."23 The correlate of that statement is that a prominent short process indicates retraction. Although there are rare instances of a bulging TM due to mucoid MEE, the short process will be visible and prominent in most cases of OME. Overall, a translucent TM with an air-fluid level almost always represents OME (Fig. 2). Even an opaque TM that has decreased mobility but is retracted with a prominent short process (Fig. 3) usually represents OME rather than AOM.
To help determine the presence or absence of MEE, pneumatic otoscopy should be performed with equipment and a technique that provide an airtight seal. Mobility of the TM is almost always diminished when MEE is present unless there is an air-fluid level, in which case mobility may be nearly normal. When the findings of pneumatic otoscopy are equivocal, tympanometry has been the most helpful adjunct in our experience. Normal results on tympanogram strongly argue against substantial MEE. A hard copy of this tracing is also useful to have for the record, especially in the event of referral to an otolaryngologist. Spectral grathent acoustic reflectometry (SGAR) is felt by some to be equally helpful.24 However, in our somewhat limited experience, the readings from the reflectometer too often seem to be in the indeterminate range, especially in infants with equivocal pneumatic otoscopie findings.
Figure 3. An opaque tympanic membrane that has decreased mobility and is retracted with a prominent short process usually represents otitis media with effusion rather than acute otitis media. (Courtesy of Alejandro Hoberman, MD.)
AGENCY FOR HEALTH CARE POLICY AND RESEARCH GUIDELINES
A task force including the American Academy of Pediatrics under contract with the Agency for Health Care Policy and Research in 1994 prepared guidelines for the management of OME in children from 1 to 3 years of age.13 There was general agreement among pediatricians and otolaryngologists with many of the recommendations, including (1) the importance of pneumatic otoscopy, and possibly tympanometry, in diagnosis; (2) the inappropriateness of multiple courses of antibiotics; (3) the lack of benefit from prophylactic antibiotics; (4) the ineffectiveness of antihistamine-decongestant treatment; (5) the possible role for tube insertion when bilateral effusions last at least 3 months with a bilateral hearing deficiency; and (6) the need for tube insertion after 4 to 6 months of bilateral effusion with a bilateral hearing deficit.
The weaknesses of the Agency for Health Care Policy and Research guidelines have been comprehensively reviewed.25 Their most obvious limitation is the narrow patient population that is addressed (ie, otherwise normal children between 1 and 3 years old with isolated OME). Most children with OME in this age group are also experiencing recurrent AOM, which may necessitate more aggressive medical or surgical management. In addition, worrisome persisting changes in the TM (eg, atelectasis and retraction pockets) with OME might warrant tube placement even if hearing is normal. Another criticism is the emphasis placed on a single hearing test, as hearing associated with OME often fluctuates. Additional controversies include (1) no recommendation that at least one course of antibiotics be used prior to tube placement; (2) adenoidectomy never being indicated for children in this age group with OME; (3) steroids not being recommended to treat OME in children of any age, although the possibility exists that there may be short-term benefits for selected patients, especially if given with an antibiotic7; and (4) no intervention being mentioned for unilateral OME lasting more than 6 months.
Because most cases of OME follow a bout of AOM, the first issue regarding management of OME is the timing of the AOM follow-up visit. Because fluid may persist after AOM for long periods, we do not recommend that the asymptomatic child have a return visit until at least 1 mondi after the initial visit. Further treatment is not likely to be beneficial in less than this time.26,27
A typical scenario in the pediatrie office is that of an irritable, younger child with an upper respiratory tract infection being brought back to the office before the scheduled follow-up appointment because of parental concern about his or her having an ear infection along with the upper respiratory tract infection. Because the otoscopie findings between AOM and OME frequently overlap, and may differ more in degree than in kind, it may be impossible to know whether the original AOM is resolving (and is, therefore, OME) or whether the symptoms are due to a new episode of AOM.1-2 In this situation, even when the diagnosis is more likely thought to be OME with an intercurrent viral illness, there is often great pressure from the parent to treat with an antibiotic. The overdiagnosis of AOM (and underdiagnosis of OME) at these follow-up visits, and the resultant overtreatment with antibiotics, may contribute in the increase of bacterial resistance.
In a recent study from England,28 parents were recruited to be "partners" in trying to reduce the use of antibiotics in AOM. If the child was not considered systemically ill, the parents were given a handout on the judicious use of antibiotics, along with a prescription for an antibiotic. They were advised not to fill the prescription unless the ear complaints were still present in 2 or 3 days. The use of antibiotics for AOM decreased by 32% from the previous year and parents were more satisfied.
One of the authors (OFR) has independently used this method, on a lesser scale and with selected families, in the difficult situation of differentiating AOM from OME during an upper respiratory tract infection. The problem of overuse of antibiotics is discussed, and the parents are given a folded prescription with die suggestion that it be filled only if symptoms do not improve within a couple of days. They are instructed to contact our office if symptoms worsen or if there is any question about filling the prescription. An expiration date is written on the prescription, canceling it if not filled within 1 week. The impression obtained from questioning die parents at later visits is that this approach has decreased the use of antibiotics and at the same time has been well accepted by parents. It tends to relieve their concern about having to make another expensive and time-consuming trip to the office if symptoms are not improving - a not infrequent scenario. Although not appropriate for all parents, this approach offers promise in reducing unnecessary antibiotics and merits further study.
Our management of OME is based on its initially favorable natural history, its multifactorial etiology, and its potential importance in abnormal speech development, recurrent AOM, and worrisome changes in the TM. As recommended by the Centers for Disease Control and Prevention (CDC),29 our initial treatment for newly diagnosed OME in an otherwise healdiy child of any age is simply watchful waiting. The parents are advised to follow up in 4 weeks (or as long as 6 to 8 weeks if a well-child appointment is due then), and to call sooner if signs of otalgia occur in the interim.
If the otoscopie findings are unchanged at that follow-up visit, we prescribe a 10-day course of an antibiotic, usually amoxicillin, and another appointment is made in 4 to 6 weeks. Although additional antibiotics at that point for any persisting OME are of questionable benefit, we sometimes consider another round of antibiotics with better coverage of H. influenzas (eg, amoxicillindavulanate and cefpodoxime) because the relative frequency of H. influenzae and M. catarrhalis is higher in OME than in AOM4 and because one study showed a short-term benefit of amoxicillin-clavulanate over amoxicillin in resolution of OME.30
We do not employ maintenance (prophylactic) antibiotics for OME because they have been shown to be beneficial only for recurrent AOM and, even then, should be used judiciously.7 Because steroids have a potential, but yet unproven, benefit/ consideration of their use is more appropriate in an otolaryngology practice when placement of a ventilation tube is being actively contemplated for chronic OME. Overall, unless the child becomes symptomatic with a new episode of AOM, antibiotic use and followup visits remain limited during the first few months of OME.
WHEN IS REFERRAL INDICATED?
A big question from die pediatrician's standpoint is when to refer the child with OME to an otolaryngologist. Referral after bilateral MEE has been present for 3 months may be appropriate, because studies have documented that such effusions are unlikely to resolve with additional time.3 Because the main issue with isolated OME is its effect on hearing, and because parents cannot accurately predict a child's hearing loss,19 referral at that point allows audiometrie testing, as recommended by the Agency for Health Care Policy and Research for bilateral effusions lasting 3 months.13
Considerations that would influence earlier referral primarily relate to hearing loss: speech delay in younger children, school-related problems in older children, and underlying sensorineural hearing loss in any child. The presence of cognitive deficits, developmental delays, or attention disorders should also influence the timing of referral. Other important factors to take into consideration include recurrent episodes of AOM, disruptive behavior affecting the family's quality of life, or worrisome changes in the TM that could have long-term consequences. Consideration must also be given to negative prognostic factors, including age younger than 2 years; fall and winter (versus spring and summer) onset; onset of the ear problems before 6 months of age; a positive family history of ear disease; and increased exposures to other children, especially in group day care settings. The availability and affordability of judicious and competent surgical intervention are obvious considerations. Additionally, from a practical standpoint, parental preference as to the timing of the referral is legitimate and extremely important.
WHEH ARE TYMPaNOSTOMY TUBES IHDICATED?
The biggest question from the otolaryngologisf s viewpoint is whether to recommend tympanostomy tubes. There is little disagreement that the child with bilateral MEE for 4 to 6 months and associated hearing loss would benefit from tubes. Likewise, mere is probably consensus that tubes are not indicated if this duration is 3 months or less with no hearing loss. Between diese scenarios is a large gray zone, and the otolaryngologist and pediatrician must consider all of the factors discussed above. In the child older man 3 years, a clinical assessment must be made as to whether the OME is related to adenoid problems, allergic rhinitis, anatomic defects, or another etiology, so that adjunctive treatment can be instituted. From a practical standpoint, tubes are far more frequently necessary when there is associated recurrent AOM than for chronic OME alone.
Unfortunately, there still seem to be as many questions as answers regarding OME, including (1) what is the significance of the relatively high percentage of positive cultures and other evidence of active infection in the face of poor responses to antibiotics; (2) how important is the temporary hearing loss for long-term speech and language development; and (3) how can we better differentiate AOM from OME so as to use fewer antibiotics? Clearly, more evidence-based research is needed. Currently, although guidelines are helpful, there are few definitely right or wrong decisions for a given child, and the physician in charge should have the freedom, working cooperatively with the parent(s), to follow the course that seems most appropriate.
OME is differentiated from AOM by both its lack of symptoms and its otoscopie findings, most importantly, the translucency and position of the TM. A translucent TM with an air-fluid level or an opaque TM that is retracted with a prominent short process of the malleus is consistent with OME. In clinically equivocal cases, we recruit reliable parents' cooperation by educating them about the judicious use of antibiotics and providing a prescription (with an expiration date) to fill in case the child's symptoms do not improve within a couple of days. In more clear-cut OME, management should initially be watchful waiting followed by one or two courses of antibiotics, generally spaced 4 to 6 weeks apart. Referral to an otolaryngologist should be considered after 3 months of bilateral OME, particularly when there is no evidence of improvement, and when hearing loss is suspected. Ventilation tubes are considered at that point based on audiometrie results, developmental issues, otoscopie findings, and prognostic factors.
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