Otitis media with effusion, also known as glue ear, is a common childhood condition in which fluid builds up in the middle ear space causing discomfort and hearing loss. The condition may affect 1 (unilateral) or both (bilateral) ears. The cause of glue ear is unclear, but it may be related to narrow or blocked Eustachian tubes that connect the middle ear to the back of the throat. The Eustachian tubes equalise the air pressure in the middle ear, and drain fluid and mucus produced as a result of inflammation, infection or an allergic reaction from it. Previous infection, swollen adenoid glands, allergy or smoke irritation may all affect Eustachian tube function. When the drainage process does not work properly, the middle ear air pressure can become negative, causing fluid to build up, affecting the movement of the eardrum and the transduction of sound (conversion of a sound wave into an electrical signal), resulting in conductive hearing loss (NHS Choices 2015).
Children are more susceptible to problems with the middle ear because the Eustachian tube is narrower and more horizontal during childhood, so it does not drain as effectively as in adulthood. As the Eustachian tube develops with age, glue ear becomes much less common. It is estimated that 1 in 5 children around the age of 2 years will be affected by glue ear, and about 8 in every 10 children will have had glue ear at least once by the time they are 10 years old (NHS Choices 2015). The most common sign of glue ear is conductive hearing impairment with associated speech and language problems; less common symptoms include ear pain, sleeping problems, balance problems, and tinnitus. If glue ear is unilateral, these are normally minor problems, but prolonged bilateral glue ear with significant hearing loss can delay speech development, affect educational progress and, in rare cases, cause permanent damage to hearing. Glue ear does not normally need treatment because the condition improves by itself, usually within 3 months. For persistent cases, surgery may be indicated. This usually means surgical drainage of fluid from the middle ear (myringotomy), insertion of grommets, adenoidectomy and tonsillectomy, or a combination of these. Normalising the pressure in the ear may reduce the symptoms associated with glue ear and may reduce the need for surgery.