HOW TO TREAT 25
ausdoc. com. au 18 JULY 2025
HOW TO TREAT 25
( see figure 4). Type A tympanograms reliably indicate healthy ears, and type B tympanograms reliably indicate reduced tympanic membrane mobility due to fluid( eg, AOM or OME). The presence of air bubbles are also reliable for fluid but are uncommon. Some common middle ear appearances are shown in figure 5. 2-5
Chronic suppurative otitis media
Chronic suppurative otitis media( CSOM) is ongoing discharge through a perforation of the tympanic membrane for at least two weeks( note that some use a six-week cut-off). This condition is debilitating and can be extremely prolonged( years), destroying the middle ear architecture and causing permanent hearing loss. The perforations are usually large( greater than 25 %), whereas AOM perforations are usually pinpoint( less than 2 %). 2-5
DIAGNOSIS
ONE of the key challenges in establishing best practices for OM management is the lack of universally accepted diagnostic criteria. Guidelines specifically for Aboriginal and Torres Strait Islander populations were updated in 2020. 3 Although developed with a focus on targeted approaches for Aboriginal and Torres Strait Islander children, the recommendations are based on established best practices, informed by international evidence, mostly from non- Indigenous populations.
They are applicable across Australia, using the high-risk category for Aboriginal children in remote settings, as well as children with a strong past or family history of OM and complications, and the low-risk category for other children( eg, Aboriginal or non-Aboriginal children in urban settings when they have no other risk factors). Clinicians are advised to use their best judgement for their local populations as evidence is scarce. If CSOM is common among the children you see, the authors suggest using the high-risk approach.
No single criterion is fully reliable in predicting bacteria in the middle ear, but bulging is the most dependable. Interestingly, fever and pain are not reliable predictors of antibiotic response. Treat pain with analgesics rather than antibiotics. Also, make sure to rule out other bacterial infections— such as meningitis, pneumonia, URTIs and UTIs— when infants have a fever rather than assume AOM when tympanic membranes look a little red. 3
Middle ear fluid, a key indicator of both AOM and OME, is difficult to detect with standard otoscopy. A meta-analysis found pneumatic otoscopy to have the best sensitivity and specificity for detecting fluid when validated using the gold standard of myringotomy. 36 While portable tympanometry is also a gold standard, it is, unfortunately, not used much in primary care.
Box 1 outlines the procedures of pneumatic otoscopy, tympanometry and audiometry.
When should we assess hearing?
The developmental milestones for hearing and speech( 3-60 months) provide a useful guide to assessing a child’ s auditory and communicative progress. AOM and OME can impact hearing as middle ear fluid impairs
A
C
Normal ear.
Acute otitis media.
Figure 5. Typical middle ear appearances.
Box 1. Pneumatic otoscopy, tympanometry and audiometry
• Pneumatic otoscopy— Pneumatic otoscopy is standard otoscopy with the addition of an insufflator( like the bulb for measuring blood pressure), which pushes a small jet of air into the external ear canal.— After achieving a reasonable seal( it does not need to be airtight), gently push in enough air to cause the tympanic membrane to move; if middle ear fluid is present, the movement is sluggish or absent.— Pneumatic otoscopy has good sensitivity and specificity and is very easy to perform but requires some subjective judgement( eg, whether the drum is moving normally or sluggishly); this takes practice.— Make sure to ask for the insufflator attachment when ordering otoscopes.
• Tympanometry— Tympanometers have microphones, speakers and manometers.
• The speaker emits a constant sound( eg, at 226Hz; infants younger than one year require 1kHz), the ear canal pressure is varied(+ 200daPa to – 400daPa).
• The microphone picks up the returning soundwaves.— The tympanometer measures the admittance( or impedance), with or without ear canal volume.— Insert the earpiece into the external ear canal until you achieve a reasonable seal( some machines beep at this time).— The tympanometer takes a few seconds to take its measurement and provides a pressure graph and volume measurements.— Tympanometry has the advantage of being objective and requires minimal interpretation.— Expert tympanometry( using B or C2 curves as abnormal) has a high sensitivity( meaning if there is fluid, it will be detected) but low specificity( meaning it overdiagnoses middle ear effusions).— Do not attempt tympanometry if there is purulent discharge in the canal.
• Audiometry
— A key aspect of audiometry is measuring the air-bone gap, which compares air conduction thresholds( hearing through headphones) with bone conduction thresholds( hearing through a vibrating bone oscillator placed on the skull).
• Air conduction— sound from the headphones travels through the ear canal and middle ear to reach the cochlea. OM can disrupt this sound transmission through the middle ear.
• Bone conduction— this bypasses the middle ear, sending sound directly to the cochlea.— As a result, if there is an impairment in sound transmission through the middle ear( eg, effusion), there will be a noticeable difference in hearing thresholds between air conduction and bone conduction.
• This difference is referred to as an air-bone gap( greater than 10dB is diagnostically significant).— Remember that the external ear must be clear of wax or fluid before audiometry.
air conduction. In most cases, especially those linked with AOM, the middle ear fluid resolves within a few weeks and in almost all cases by three months, with no need for immediate hearing tests. However, audiometry is recommended for children with recurrent OM( three or more in six months, four or more in 12 months), persistent OM( for longer than three months) and those from priority groups( eg, OM history, family history, whether Aboriginal or not). It is essential to monitor for signs of hearing loss or language development delays. If hearing loss exceeds 30dB, consider referral for hearing aids. 3
It is good practice to arrange at least one hearing test in all children before they start school as mild to moderate hearing impairments can go unnoticed but have significant impacts on development. Newborn screening excludes hearing loss below 30dB, which is usually sensorineural, but does not exclude later-acquired OM-related conductive
B
D
Otitis media with effusion, with ventilation tube in situ.
Chronic suppurative otitis media.
loss( often greater than 30dB). Hearing loss in children is often missed, and regular hearing assessments ensure early detection and management of hearing issues, contributing to better developmental outcomes. 1, 3, 37
The milestones outlined in tables 1 and 2 for infants aged 3- 60 months are a good general guide but are not comprehensive.
MICROBIOLOGY
AOM often follows coryzal
Images courtesy of Professor Harvey Coates.
Table 1. Hearing-related developmental milestones
Time frame
3-6 months
Nine months
By 12 months
At 20 months
At 24 months
At 30 months
At 48 months and 60 months
Milestone / s
Infants engage in social smiling and early turntaking in conversations( laying the groundwork for speech and social communication)
Feeding and oral co-ordination support speech development, but intentional gestures, such as pointing, also become prominent( signalling an emerging understanding of non-verbal communication)
Children typically begin to say“ mama” and“ dada” and understand more words than they can express( setting the stage for rapid vocabulary growth)
Children speak more clearly and begin using two-word combinations( marking a critical period of language development called the‘ language explosion’); additionally, this age often involves more complex gestures, such as nodding or shaking the head
Children know more than 50 words and connect them into basic phrases while understanding and following more complex instructions
As children use two or more words in simple sentences, they begin to express a broader range of ideas and emotions and their comprehension expands rapidly
The milestones at later stages, such as understanding multi-step instructions at 48 months and engaging in clear conversations at 60 months, could also be further linked to key cognitive developments that enhance their communication abilities, social interactions and ability to express desires, emotions and reasoning more clearly in increasingly complex social settings
Source: Menzies School of Health Research 2020 3, Aracy PSB et al 2023 17, Boynton KA 2021 18, Brennan-Jones CG et al 2020 19
symptoms, typically indicating a viral illness, with the development of AOM often lagging by 3-4 days. 38 Viral pathogens can be isolated from middle ear fluid or the nasopharynx in nearly all children with AOM with modern PCR. However, viral detection rates halve when relying solely on cell cultures. Common viruses associated with AOM include rhinovirus, respiratory syncytial virus
38, 39
( RSV) and influenza.
Antibiotics
Bacterial pathogens play a key role in AOM, with the most common being Streptococcus pneumoniae and non-typeable Haemophilus influenzae, often following viral URTIs. 40-42 Moraxella catarrhalis, another significant pathogen, shows resistance to amoxicillin, the first-line antibiotic. Despite this resistance, trials show no clear benefit in using broader-spectrum antibiotics PAGE 28