Otitis media with effusion ( Part 1 )

Otitis media with effusion (OME) describes perfectly the pathology. It describes an inflammatory condition of the middle ear cavity caused by a negative middle ear cavity pressure. This results in fluid being drawn out from the inflamed mucosal lining, into the middle ear space as an effusion.

So how this comes about? What are the symptoms? Our middle ear space cavity connects with the back of our nose by the Eustachian tube. This tube is usually closed, to prevent bacteria from entering the sterile middle ear. However during swallowing, tiny muscles open this tube for a fraction of a second, and air is pushed up the tube, into the middle ear space. This maintains a middle ear air pressure that is the same as the atmospheric pressure outside the eardrum. When the air pressures on either side of our eardrums are the same, our eardrums are at their most flexible and responsive to sounds, and our hearing is at its best.

Normal Eardrum

When middle ear pressure drops, the eardrum is drawn inward and cannot vibrate easily to sounds; hence our hearing becomes impaired. As the inflammation increases, effusion fluid fills the middle ear space. When this fluid contacts the eardrum from within, it prevents it from moving. Now our hearing gets even worse. Hence patients with partial or complete OME suffer with the following symptoms:

• ear pressure sensations  during the descent in an aeroplane,

• bubbling noises during swallowing,

• hearing loss like having water in the ears after a shower,

• ringing noises called tinnitus from within their ears and

• sometimes pain in the ear.

Otitis media with effusion

Any condition that can cause obstruction of the Eustachian tube can cause OME in one or both ears. So what conditions would make the tube less easier to open during swallowing, or cannot open at all. Common causes are nose allergies, viral infection of the upper nasal airway and middle ear infections. Less commonly are tumours like cancers of the naso-pharynx. Of these, treating your nose allergy and taking precautions not to catch a cold, may help in preventing OME.

OME is quite common in children. A Chinese University of Hong Kong study by MCF Tong et al shows that OME in Hong Kong is present in one/both ears of 9% of children aged 2-10 years. This prevalence is no different from similar studies in the West. OME in children can causes hearing difficulties, and therefore speech delay, inattention, poor behaviour and poor school performance as they cannot hear well.  As middle ear infection is the commonest infection of childhood, it is naturally a major cause of OME in kids. A child’s nose is small and narrow, and the immunity of the child remains underdeveloped against the challenge of viruses and bacteria. In addition the rising trend of nasal and food allergies is thought also to be a factor.

In teenagers to adulthood in Hong Kong, middle ear infections are less common. So for adults, when OME is noted, cancer of the nasopharynx is a possible cause and should be excluded by an ENT examination. The south China region has the highest incidence of nasopharyngeal cancer in the world, with about 30 new cases per 100,000 population diagnosed each year. Early diagnosis is vital to good prognosis.

In summary, otitis media with effusion causes blocked ears and hearing loss. It is usually temporary and lasts a few weeks especially after a cold. If it persists, an ear and/or nasopharynx examination is recommended with your doctor. In children, it can cause speech delay whilst in aduts, cancer of the nasopharynx has to be excluded.

The Chinese version of this article was published in Hong Kong Economic Journal on June 6, 2013 and Part 2 will be published in Hong Kong Economic Journal on June 20, 2013.