It isn’t unusual to find fluid in the human ear. This condition, known as serous otitis media, is relatively common in children, particularly those who are exposed to second-hand smoke, who are recovering from ear infections or who have allergies or colds. According to a December 2007 article in “American Family Physician,” by age 3, more than 80 percent of children have been diagnosed with ear infections, otherwise known as acute otitis media. Many of these children subsequently develop persistent fluid collections in the middle ear space, and some experience temporary hearing loss as a result.
The structure of the ear contributes to abnormal accumulations of fluid, or effusions. The middle ear space, a hollow chamber behind the ear drum, normally connects to the atmosphere via the Eustachian tube, which opens in the back of the throat. If this conduit is plugged – a condition called Eustachian tube dysfunction – the pressure between the middle ear space and the outside air cannot equalize. The cells that line the middle ear chamber continue to use oxygen as they continue their metabolic activities, and soon a negative pressure develops within the chamber. This pulls tissue fluid into the space, which has no way to drain because the Eustachian tube is plugged. Once an effusion has formed, it is susceptible to bacterial colonization.
Since children – the most likely age group to acquire middle ear effusions – cannot always vocalize their symptoms, parents and health care providers need to be alert to the possibility of persistent serous otitis media. If a child doesn’t seem to hear normally, is unusually irritable or rubs at one ear constantly, a doctor should examine his ears. Usually a middle ear effusion can be visualized through the ear canal with a doctor’s otoscope. If the middle ear space is not readily visible, a simple test called a tympanogram can be used to evaluate the mobility of the eardrum and determine if an effusion is present. Children who are recovering from a bout of acute otitis media should be seen by their doctors two to three weeks after they’ve finished their antibiotics to ensure clearing of the middle ear space.
Nearly all cases of uncomplicated serous otitis media resolve spontaneously, but this can take several weeks or even months. A 2007 Cochrane review demonstrated that the use of decongestants and antihistamines to hasten healing is not helpful. In the absence of an infection, antibiotics are not beneficial, either. Any effusion that has not resolved within three months may require more aggressive treatment, and any evidence of hearing impairment due to a middle ear effusion merits further evaluation.
Persistent middle ear effusions sometimes re-infect, leading to a cycle of recurrent acute otitis media or even chronic otitis media. In addition, such effusions can thicken, leading to a condition known as “glue ear.” This can eventually impair hearing. In such instances the effusion may have to be surgically suctioned from the middle ear space. Small plastic tubes are subsequently inserted through the eardrums to assume the role of the dysfunctional Eustachian tubes. Untreated cases of glue ear may progress to a condition called otosclerosis, in which the tiny bones that transmit acoustic vibration through the middle ear become fused. This can result in permanent hearing loss, although corrective surgery can partially restore hearing.
Avoiding risk factors helps to limit the occurrence of middle ear effusions. Children and adults who are prone to ear problems should not be exposed to tobacco smoke, and those with allergies should avoid offending allergens whenever possible. Reducing the incidence of upper respiratory infections through frequent hand washing and avoiding people who are ill may help. Older children and adults whose ears plug frequently may benefit from performing a Valsalva maneuver, which involves pinching the nostrils together and blowing gently to “pop” the ears.