11- Otitis media with effusion

Childhood otitis media with effusion

Following an episode of otitis media many children will be slightly deaf for several weeks. This is due to an accumulation of fluid in the middle ear. Sometimes fluid accumulates without a prior episode of acute otitis media – a middle-ear effusion. Provided this is short-lived and resolves completely it is a normal part of childhood and needs no treatment. If fluid persists in the middle ear with an intact drum, i.e. no perforation, for a continuous period of 3 months or more this is pathological and is termed ‘otitis media with effusion’ (OME), or ‘glue ear’. ‘Serous otitis media’ and ‘secretory otitis media’ are older descriptive terms still often used for this condition. Avoid calling this ‘chronic’ as the term ‘chronic otitis media’ is best reserved for con- ditions in which the eardrum has perforated.

Prevalence

Fluid in the middle ear affects most children at one time or another. In up to a third of children it is at some time in their childhood persistent for 3 months or more (OME). OME is commoner in the winter. It is commonest in small children and those of primary school age and may cause significant deafness. It may be responsi- ble for developmental and educational impairment, and if untreated may result in permanent middle-ear changes.

Aetiology

Many cases of OME follow an acute otitis media and are due to persistence of fluid after the acute infection has subsided. In other cases the aetiology is unknown. The adenoids have an important role. Adenoidectomy can be curative in some cases of OME. It is thought that very large adenoids can obstruct the Eustachian tube so that the middle ear is poorly ventilated and fluid accumulates but this must be rare. More likely the adenoids act as a reservoir for clumps of bacteria, which are encased in a polysaccharide matrix and resistant to treatment with antibiotics or to the normal physiological defence mechanisms (a ‘Biofilm’).
Passive smoking, nasal allergy, and early exposure to pathogens such as occurs in crèches and day-care facilities for groups of young children have all been implicated in OME. Cleft palate children are especially susceptible to OME. This is due to palatal mus- cle dysfunction, which affects the Eustachian tube. Children with Down Syndrome and with mucociliary function disorders are also at increased risk.

Presentation and effects 

Fluid in the middle ear interferes with transmission of sound so a conductive deaf- ness ensues. This is rarely severe – about 30 decibels is usual – and children can often manage very well. If it is persistent and bilateral it will cause noticeable problems – often enough to affect adversely the child’s school performance. Parents complain that the child won’t come when called, turns the television up loud, shouts and becomes easily frustrated and bad-tempered. There is no pain, but some parents notice that the child is clumsy and unsteady. Otoscopy will often show the char- acteristic dull yellowish appearance of fluid behind the drum but findings can be difficult to interpret especially in young children (Fig. 11.1). An audiogram or hear- ing test confirms the conductive deafness. A ‘flat’ tympanogram is added evidence (Fig. 11.2). In children under four, pure tone audiometry is difficult and unreliable but an experienced and trained tester will usually be able to get a good estimate of the child’s hearing thresholds by other methods, e.g. observing the child’s behaviour in response to sound stimuli. 

Management of OME 

Many children will improve spontaneously. GPs will often try a single course of antibiotics to help shift an established effusion but there is little point in persisting with repeated antibiotics.

Figure 11.1 OME. Note the yellow discoloration of the tympanic membrane (courtesy of 

M.P.J. Yardley).

 If there is a predisposing condition, e.g. al- lergic rhinitis, upper respiratory sepsis or cleft palate – this may need treatment on its own merits. Treatment of OME is mainly geared toward improving the hearing. 

Figure 11.2 Normal tympanograms.

The traditional approach has been the insertion of a small tube in the eardrum (grommet, Fig. 11.3).

Figure 11.3 Right tympanic membrane with grommet in place

This is done under a general anaesthetic follow- ing puncture of the drum and aspiration of the fluid (myringotomy). The grom- met now permits air entry into the middle ear, which stops re-accumulation of fluid. Hence grommets are sometimes referred to as ventilation tubes or ‘vents’. Most ‘vents’ will extrude after a period of up to 1 year and the child needs no further treatment. Grommets or ‘vents’ are effective but associated with some morbidity, e.g. the risk of persistent perforation of the drum (about 5%) and of infection and discharge due to what amounts to a perforation of the drum while the grommets are in place.

Adenoidectomy is effective but can be complicated by bleeding. Some ENT surgeons combine grommets with adenoidectomy, especially in children with recurrent effusions or where there is evidence of adenoid hypertrophy, e.g. upper airway obstruction.

Many parents and doctors are concerned about the complications of grom- mets and prefer to encourage the child to use a hearing aid for a period of several months to a year or so while the middle ear effusions resolve spontaneously. In addition to conventional hearing aids a simple amplification device that the child can wear on a headband (e.g. ‘Softband’, Fig. 11.4) may suffice in cases where the hearing loss is mild.

Figure 11.4 (a) Child using ‘Softband’ amplifier and (b) close-up of ‘Softband’.

Treatment of OME in children

•  Mild cases: treat expectantly. Advise the parents and teachers re strategies to help the child’s hearing. This includes getting her attention before speaking, cutting out background noise and sitting her at the front of the class.
•  Prolonged cases may need referral for grommets, a hearing aid, or in recurrent cases adenoidectomy.

Adult OME

OME in adults usually follows an upper respiratory infection. Improvement is gradual and spontaneous, but may take up to 6 weeks. A nasal decongestant – for a short period – may hasten resolution. An effusion can also follow sudden changes in ear pressure – e.g. deep sea diving or rapid descent in an aircraft (barotrauma), can persist after an episode of acute otitis media as in children or may be a sign of Eustachian tube obstruction. Rarely it can be a presentation of nasopharyngeal malignancy. If there is no obvious explanation such as barotrauma or a recent ear infection examination of the nasopharynx to exclude tumour is essential.