What is glue ear, what are the causes and how can it be treated?
What is glue ear?
Glue ear (also known as otitis media with effusion, or OME) is a condition in which fluid accumulates in the middle ear: the area behind the ear drum.
The fluid impairs the movements of the ear drum and therefore reduces the conduction of sound from the ear drum to the hearing organ (inner ear), resulting in reduced hearing.
It is the commonest cause of partial deafness in young children. It is estimated that one in four children are affected with glue ear at some stage of their lives.
What causes glue ear?
Risk factors for glue ear are: young age (especially under six), winter months, regular day care with many other children (at nursery or school), a family history of glue ear (in siblings and parents) and passive smoking. Nasal allergies and acid reflux may also be involved in some cases.
Children with certain conditions such as Down’s syndrome or cleft palate are also commonly affected, and their glue ear tends to be more persistent.
The Eustachian tube (which connects the back of the nose to the middle ear) normally plays an important role in maintaining equal air pressure between the outside and inside of the middle ear. This is most obvious as the ears “pop” when flying. In reality, a little squirt of air usually passes up the Eustachian tube to the middle ear whenever we yawn or swallow. When the tube becomes obstructed, the lining of the middle ear becomes unhealthy, causing production of fluid and mucus- the “glue”. There is an excellent NHS choices video explaining all this (plus some of the treatments) available here.
In children the Eustachian tube is more horizontal and smaller than in adults, which is one of the reasons why glue ear is relatively common in children.
Children are also more prone to colds and tend to have quite large adenoids at the back of the nose: these factors are also thought to be important.
The chance of having glue ear reduces as children get older. The glue tends to come and go, resulting in fluctuating levels of hearing. Left alone, about half of children with glue ear at a particular time will have improved within three months- so a watchful waiting policy is often reasonable in the first instance.
What are the effects of glue ear?
The main effect of glue ear is reduced hearing. This is often suspected by parents and teachers, but is not always obvious- particularly if the affected child is young.
Reduced hearing itself may have several consequences, which may be subtle and will vary from child to child. These include poor listening skills, inattention or poor concentration, frustrated or withdrawn behaviour, speech delay and other educational problems.
It is important to note that while some young children are certainly held back by their glue ear, many others do not have major problems. Providing they are well supported, many will do well without active treatment. Glue ear itself does not cause long term damage to the ear or the hearing organ.
How is glue ear diagnosed?
Some children are referred to ENT and audiology services after their parents and/or teachers become concerned about their hearing. In other cases, routine hearing screening on school entry may pick up hearing loss.
Examination of the ears may demonstrate fluid (glue) behind the eardrum, but this is sometimes difficult to see in young children with small, waxy ear canals.
Pressure tests (tympanograms) are usually an accurate method of diagnosing glue ear.
Hearing tests (audiograms) will typically show a mild conductive hearing loss: reduced conduction of sound through the middle ear as a result of the glue. The hearing organs are not affected.
Treatment options for glue ear should be tailored to the individual child. They are presented below in a sensible order, not in order of preference.
In all cases, the day-to-day consequences for the child of any hearing loss should be assessed: how much is the child affected, particularly in social situations and education?
A long duration of symptoms and other factors (such as other medical problems or learning difficulties) are also worth considering when planning treatment.
The NICE Guidelines for Glue Ear recommend that hearing assessments should be carried out at the first clinic visit and then after three months- to check whether the glue ear has persisted. This will allow the glue ear time to settle without treatment in a significant number of children. Details are available at http://www.nice.org.uk/nicemedia/pdf/CG60fullguideline.pdf
Essential simple measures
While waiting to see if the glue settles on its own, parents and teachers should be understanding and encouraging, recognising that there may be associated problems with behaviour and education, and be aware of ways to reduce any impact of reduced hearing for the child. These include sitting at the front of the class, direct face-to-face speaking (to allow some lip reading), and checking carefully that the child hears and understands what is said. Care should be taken in certain situations, such as when crossing the road, where reduced hearing may have dangerous consequences.
Autoinflation (popping the ears)
During this initial monitoring period, some children may be able to try to “pop” their ears, by pinching the soft part of the nose and trying to blow the nose at the same time- as when descending on a flight. This is called autoinflation. This can be difficult for younger children, and so an Otovent® balloon may also be tried: a nozzle is inserted into a nostril, the nose is then pinched, and the child is then asked to try to inflate the balloon http://www.otovent.co.uk. A video of how the balloon is used can be viewed here. The balloon can be prescribed, or is available widely online for about £6-7. Evidence to support autoinflation is relatively limited, but positive nonetheless. A review of the evidence is available here.
Digital hearing aids are an effective way of treating the hearing loss associated with glue ear, amplifying environmental sounds, bearing in mind that the hearing organs are unaffected by the glue: an analogy is simply turning up a clear digital radio signal. A range of hearing aids are provided and serviced free on the NHS, and others are available privately. They have no major side effects, are suitable for patients of any age and, after some initial programming sessions by an audiologist, are straightforward to fit and use. They can also be personalised, and are generally well-tolerated. Another advantage is that they can be used in particular situations such as school or work, but taken out at other times, such as at night, or during periods where glue ear has resolved. Bone conducting hearing aids are sometimes used for young children, those with infected or narrow ear canals, and for some with learning difficulties who struggle with hearing aid moulds in their ears.
Grommets, also known as ventilation tubes (VTs) have been used as a treatment for glue ear for many years. They are small bobbin-shaped tubes which are inserted into the eardrum. Many different types are available, but the commonest ones are made of Teflon, an inert type of plastic.
Grommets are usually inserted under general anaesthetic, a procedure which takes about 20-30 minutes in total. Some cooperative teenagers and adults may have this done using local anaesthetic.
As with other treatments for glue ear, grommet insertion is considered very carefully, depending upon a number of individual factors, including the patient's age, history of middle ear infections, pain, speech delay, learning or behavioral difficulties, or problems with other treatments.
It can also depend on the appearance of the eardrum (for instance whether there is a retraction pocket, which is a localised area of scarring that may lead to problems). They are discussed in more detail under the separate grommets section.
Adenoidectomy (removal of the adenoids)
The adenoids lie at the back of the nose, and are fleshy tissues which are part of the basic immune system. They can be thought of as the tonsils of the nose, picking up bacteria and virus particles and relaying them to the immune system. In reality, their role in the immune system is relatively limited, particularly after two or three years of age. They are largest in pre-school children, gradually shrinking towards adolescence.
Lying at the back of the nose, the adenoids sit between the openings for the Eustachian tubes, which themselves connect the nose to the middle ears, allowing the ears to "pop". Very large adenoids may physically block the tubes, making glue ear more likely, but even small adenoids may reduce the effectiveness of the Eustachian tubes. This may be as a result of them harbouring bacteria and mucus. In either event, there is good evidence that removal of the adenoids is an effective treatment for glue ear, regardless of their size. Adenoid removal also improves the duration of benefit of grommets, so that grommet insertion and adenoidectomy are commonly performed at the same time- particularly in children with repeated glue ear, those who have had grommets before and those with blocked noses. Recent UK evidence (the TARGET study) is summarised at http://www.ncbi.nlm.nih.gov/pubmed/22443163 and adenoidectomy is also discussed in the NICE guidelines for glue ear http://www.nice.org.uk/nicemedia/pdf/CG60fullguideline.pdf
Further information about the adenoids and adenoidectomy procedure can be found in the respective section.
Special cases: Down Syndrome and Cleft Palate
The NICE Guidelines also look at children with Down Syndrome or cleft palate who are at particular risk of glue ear- most likely as a result of reduced effectiveness of the Eustachian tubes. As such, these children are likely to have more persistent glue ear, often lasting on and off into adolescence. Multiple repeated grommet insertions may eventually cause problems for the eardrums, and so hearing aids and other non-surgical methods are preferred in many cases.
Treatments for glue ear with no proven benefit
A review of the evidence by NICE (http://www.nice.org.uk/nicemedia/pdf/CG60fullguideline.pdf) has demonstrated that the treatments below have no strong evidence to support them and as such are not recommended for the management of glue ear:
• topical or systemic antihistamines
• topical or systemic decongestants
• topical or systemic steroids
• cranial osteopathy
• dietary modification, including probiotics
Flying and diving with glue ear and grommets
Children and adults with glue ear will struggle to "pop" their ears and equalise when flying, particularly on descent as the air pressure increases. This may be very painful. I recommend having simple painkillers available for children (paracetamol and particularly ibuprofen, which works more effectively for ear pain), and measures to help the ears to equalise (water, something to eat or suck, and decongestant drops or spray eg Otrivine 30 minutes before take off and landing). Once grommets are inserted, no such problems should occur, as the ears will not need to pop (unless a grommet becomes blocked).
Diving increases the pressure on the ears far more. In glue ear, this will be extremely painful and likely to result in trauma to the eardrum and perforation. With grommets in place, high pressure water will pass through into the middle ear, again causing pain and trauma. For these reasons, swimming should be restricted to the surface.
An excellent evidence-based review article on glue ear is available by clicking here.