Childhood otitis media ii. specialist view

Summary
Three presentations of otitis media are common in children: acute, recurrent and otitis media with effusion (glue ear). Antimicrobial treatment lessens the duration of pain in acute otitis media and may prevent serious complications. Recurrent otitis media may be managed best by treating each attack, but, if it is severe, preventive treatment may help. Otitis media with effusion usually resolves without surgery, but, if it is chronic, ventilation tubes may be required. These tubes effectively restore hearing and relieve other symptoms, but do not cure the underlying causes. Recurrences can occur when the tube ceases to function and reinsertion may be needed. Otitis media with effusion may have long-term effects on educational performance.

Introduction
Otitis media can be classified as:

• acute (suppurative) otitis media
• otitis media with effusion (glue ear)
• chronic suppurative otitis media
  • without cholesteatoma
  • with cholesteatoma

Acute otitis media and glue ear are closely related and can merge into one another. While acute otitis media has a rapid onset of symptoms and signs of inflammation, in glue ear there is a relatively asymptomatic effusion in the middle ear.

Acute otitis media
Diagnosis
Not all cases present with the typical picture of significant earache, sleeplessness, pyrexia and a bulging red tympanic membrane. Complaints of earache can be muted and only represented by irritability or bad behaviour. Pyrexia may be minimal and tympanic membrane changes can be almost identical to those of glue car. However, the association of several of these symptoms and signs usually alerts practitioners to the diagnosis, especially if they are familiar with the features of the normal tympanic membrane. In acute otitis media, redness, bulging and apparent opacity of the tympanic membrane will usually be seen. If an otoscope with an attached bulb is used to puff air into the ear canal, the mobility of the tympanic membrane will be reduced or absent. The view may be obscured by wax or by struggling infants, but an accurate clinical diagnosis is usually possible in most cases. Tympanometry may help, but is often unsatisfactory in the difficult situations where it would be of most assistance. Perforation of the tympanic membrane in acute otitis media is the usual cause of discharge in the child's external auditory canal as primary otitis externa is uncommon in young children. Parents can be reassured that perforations usually heal spontaneously.

Treatment (Fig. 1)
The bacteria most commonly grown from the exudate of acute otitis media are Streptococcus pneumoniae, non-typeable Haemophilus influenzae and Moraxella (Branhamella) catarrhalis¹. Unfortunately, vaccines against Haemophilus influenzae are only effective against type b organisms and I do not believe they will reduce the incidence of otitis media. Most studies report growth in ~ 50% of cases, but in a recent study which maximised the chances of growth, bacteria were grown in 90%.²

A recent controlled study of antibiotics in otitis media³ showed that treatment failure was 8 times more likely in the placebo group than the treatment group. Antibiotics relieved pain more rapidly than placebo and, the day after entry into the study, the placebo group had a significantly higher incidence of fever. Analgesic consumption, duration of crying and absence from school were also higher in the placebo group. Antimicrobials may also be responsible, at least in part, for the current rarity of serious complications, which had an incidence of up to 20% in the pre-antibiotic era.¹

Despite the spread of ampicillin-resistant Haemophilus influenzae, amoxycillin (40-50 mg/kg/day) is still, on empirical grounds, an appropriate first choice antimicrobial in Australia (the incidence of beta-lactamase-producing organisms in otitis media in Australia is not known, although high incidences are present in respiratory tract isolates).¹ Amoxycillin/potassium clavulanate and cefaclor are also satisfactory¹ and are especially appropriate if improvement does not occur in a sick child after 24-36 hours of treatment with an antimicrobial such as amoxycillin or in the case of an early recurrence (within one month). These drugs may become more appropriate as first choice medications if the effectiveness of amoxycillin wanes as resistance increases.

Fig. 1
Acute otitis media

Recent concerns about the adverse effects of trimethoprim/ sulfamethoxazole have led to reduced usage of the combination, but it may still be considered if the child is allergic to penicillin.¹ The main alternatives in these children are cefaclor and trimethoprim. Cefaclor has an incidence of cross-sensitivity with penicillin4 so trimethoprim may prove to be the drug of choice in the case of penicillin allergy, although it is comparatively unproven for otitis media. Erythromycin, penicillin, 'first generation' cephalosporins (e.g. cephalexin) and sulphonamides alone do not adequately treat the common organisms.¹ Analgesics may also be needed.

Myringotomy is rarely used in Australia for acute otitis media. It may have a place if there is severe, persistent pain which does not respond to antimicrobials or if there is concern about a possible complication.

Complications
The effusion of acute otitis media tends to clear with time, but in 20-40% of cases, patients' ears will still have an effusion (otitis media with effusion) after one month and in 10% of cases after 12 weeks.¹ Children should be checked between 3 and 6 weeks after an attack of acute otitis media to make sure that the ears do clear. Recurrent attacks will interfere with natural resolution and make chronic otitis media with effusion more likely.

Other sequelae are less common (see Table 1).

Recurrent otitis media
Recurrent otitis media may be defined as 3 acute attacks in 6 months.¹ This is more likely in the presence of otitis media with effusion. Many cases can be managed by general practitioners, but referral to a paediatrician may be indicated if an underlying medical cause is suspected, such as a possible immune deficiency.

• chronic tympanic membrane perforation
• chronic suppurative otitis media
• cholesteatoma
• mastoiditis
• facial palsy
• suppurative labyrinthitis

Intracranial

• meningitis
• cerebral thrombophlebitis
• lateral sinus thrombosis
• benign intracranial hypertension
• intracranial abscess

Generalised

• septicaemia
• pyaemia

Preventive treatment, usually prophylactic antibiotics or the insertion of a ventilation tube (grommet), may be worthwhile if the attacks are frequent (e.g. every 2-3 weeks) or severe (e.g. significant pain or sleep loss). In contrast, if the attacks are infrequent (e.g. second monthly) or not severe, prophylactic treatment is probably not worthwhile. This is because, even if prophylaxis is completely successful, it will only prevent one or two attacks in a 3-month course of antimicrobials or 4 attacks in the average duration of action of a ventilation tube (9 months). If a prophylactic antimicrobial is prescribed, amoxycillin 25-50 mg/kg/day is appropriate. Trimethoprim/sulfamethoxazole is an alternative which can reduce recurrences, but the possibility of serious adverse effects from sulphonamides should be taken into account.¹

Ventilation tubes are considered if the ears do not clear between attacks (i.e. there is concurrent otitis media with effusion), if antimicrobials are not tolerated (or have failed) or if attacks are very severe. Ventilation tubes usually eliminate or greatly alleviate recurrent otitis media while they are functional, but success cannot be guaranteed. With a ventilation tube in situ, otitis media usually presents with aural discharge which often clears quickly. If discharge persists, pseudomonas could be involved and ear drops (often containing an aminoglycoside) may be necessary. Although there is a theoretical risk of sensori-neural deafness due to the aminoglycoside, I have never seen this complication.

Adenoidectomy may help if the above measures fail⁵, but I rarely use it unless adenoids are enlarged. Tonsillectomy may help in children whose recurrent otitis media is accompanied by tonsillitis.

Otitis media with effusion (glue ear)
The pathogenesis is probably multi factorial¹, but eustachian tube hypofunction, leading to inadequate middle ear aeration, may be the immediate cause. Glue ear often follows acute otitis media or a viral upper respiratory infection. Its prevalence is highest at about two years of age⁶, hence factors related to immaturity probably contribute to eustachian tube hypofunction. Some studies have shown an increased incidence of glue ear in association with parental smoking.¹

Diagnosis
Symptoms include deafness (often presenting as speech delay or poor speech), pain or discomfort (which may cause sleep loss), irritability, bad behaviour and, in 20% of patients, imbalance - so deafness is not the only symptom which may require relief. In some cases, otitis media with effusion is asymptomatic.

The appearance of the tympanic membrane may be little different from normal, but any departure from the normal should arouse suspicion of glue ear. Usually the tympanic membrane becomes retracted, opaque and discoloured. Blood vessels (often running radially) may be visible on the surface of the membrane and its mobility is usually reduced (hence the general practitioner may find a pneumatic otoscope useful). Alternatively, a fluid meniscus or bubbles in fluid may be visible through the tympanic membrane.

Audiometry is usually diagnostic in co-operative patients.

Treatment
i. Conservative
Most cases resolve spontaneously in 3 months. Therefore, if otitis media with effusion is asymptomatic or if mild deafness is the only significant symptom, it is reasonable to wait until the condition has been present for 3 months before surgical intervention. Meanwhile, social management should be undertaken. This can include changing the child's position in the classrooom, advising extra caution on the roads and encouraging the parents to stop smoking. Auto-inflation of the middle ear is not helpful, apart from the 'Otovent' device which is reported to improve the resolution rate significantly in the short term.¹ However, it is not yet known if the device reduces the need for surgical treatment.

ii. Drugs
During the observation period, medical treatment can be used. A course of antibiotics of 10-30 days' duration is probably somewhat efficacious1 if they have not already been tried.

Steroids, with or without antibiotics, have been studied with conflicting results, mostly favouring steroids by a small margin. The potential benefits may be outweighed by the risks and the incidence of relapse.

Antihistamines, nasal decongestants, mucolytic agents and non-steroidal anti-inflammatory drugs are not beneficial.1 Successful treatment of allergic or infective rhinitis (or sinusitis) may cure otitis media with effusion.

iii. Surgery
If after 3 months there is no resolution, the insertion of ventilation tubes immediately restores the hearing and relieves other symptoms by aerating the middle ear. However, one must be flexible and treat the patient, not just the disease. Earlier insertion may be indicated in some circumstances including severe pain, worrying tympanic membrane changes, unsteadiness, irritability and communication problems. Conversely, surgery can be delayed if there are minimal or no symptoms or if there is evidence of improvement.

Ventilation tubes are beneficial while they function, but afterwards, if maturation has not relieved the underlying causes of eustachian tube hypofunction, there may be a recurrence which requires ventilation tubes to be reinserted.

Adenoidectomy is the other surgical treatment frequently used for glue ear, but there is no agreement about its efficacy. It is a bigger operation than ventilation tube insertion and the results may not be as beneficial. I only perform adenoidectomy (usually combined with ventilation tubes) in patients with repeated recurrences of otitis media with effusion or when there is evidence of significant adenoid hypertrophy.

Tonsillectomy can also confer benefit in glue ear if enlarged tonsils cause respiratory obstruction or if acute otitis media occurs in association with recurrent tonsilitis. In such cases, indications for tonsilectomy in its own right will be present.

Complications
It is not known if deafness due to glue ear has a long-term effect on speech and education. There is evidence that children become 'otitis prone' during the first 3 years of life and that educational damage may be greatest during this time.⁷

Very persistent effusions may be associated with middle ear complications e.g. adhesive otitis media, tympanic membrane atrophy.

Chronic suppurative otitis media
Chronic suppurative otitis media is usually characterised by a chronic perforation of the tympanic membrane which may be moist (suggesting inflammatory activity) or dry (suggesting inactivity). It may or may not be accompanied by cholesteatoma.

Cholesteatoma is a destructive, serious condition consisting of a collection of keratinising epithelium in the middle ear or mastoid usually associated with a perforation which is most frequently in the attic or postero-superior portion of the tympanic membrane. Unless discharge (which may be foul-smelling) obscures vision, there is often white matter visible in the perforation and usually an incomplete margin of tympanic membrane remnant surrounding the perforation.

Chronic suppurative otitis media usually requires surgery. Referral to an ear, nose and throat surgeon is appropriate, especially if cholesteatoma is suspected.