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Otitis media is a nonspecific term describing inflammation of the middle ear, and is classified according to its clinical presentation.(1) Acute otitis media is characterized by rapid onset of symptoms, and episodes are more frequent in the first 3 years of life. Acute otitis media is the most frequent diagnosis in infants and children who visit physicians because of illness.(2) Acute otitis media occurs in adults, but with much less frequency. Otitis media with effusion (accumulation of liquid in the middle ear cavity) differs from acute otitis media in that signs and symptoms of acute infection are absent. Whether the type of effusion is serous, purulent, or mucous it is often difficult to determine due to the opacity of the tympanic membrane.
The middle ear and its functions are best described as an air-filled cavity that begins at the tympanic membrane and extends to the nasopharynx via the eustachian tube. Its primary functions are the regulation of atmospheric pressure between both sides of the tympanic membrane, protection from nasopharyngeal secretions, and draining secretions from the middle ear into the nasopharynx. In the adult, the eustachian tube lies at a 45° angle from the horizontal plane. In children that angle is only 10°. This may indeed help explain the increased rate of infection in infants and children, since the degree of angulation may cause improper drainage. Also, the tensor veli palatini, the muscle responsible for eustachian tube opening is less efficient.
Several risk factors contribute to the higher incidence and frequency of otitis media:
Season: Frequency of otitis media is greatest in the winter months and appears to parallel outbreaks of upper respiratory tract viral infections.
Malformations such as cleft palate, downs syndrome, and adenoid hypertrophy increase the likelihood of acute otitis media infections and recurrences.
Environmental Factors that increase the likelihood of infections are parental smoking, attending day care centers, and history of recurrent acute otitis media or respiratory tract infections in siblings.
Race: The incidence of acute otitis media is more predominant in Caucasians than Black Americans, and Native Americans and the Inuit seem to be particularly at risk. The differences among races are attributed to anatomic differences, living conditions, availability of medical care, and the generally small sample size of groups studied.
Age at first episode: The younger the child's first episode of otitis media, the greater the likelihood of developing recurrent, more severe episodes.
There are basically two situations which may occur with middle ear disturbances. First, a pathogen, such as a bacteria, may get into the middle ear and, as it propagates, fluid is unable to drain due to swelling and inflammation. Potential causes of this may include head trauma from birth or from an accident, or Eustachian tubes congested from allergies or colds.
Secondly, some experts feel that chronic ear complaints may be initiated by food or environmental allergies. Allergies could cause a fluid buildup in the ear, which may create pain or pressure in the child, but it is not an infection. However, this buildup can become a ripe medium for pathogen invasion. The biggest food culprits are wheat, corn, and dairy. Other common problem foods include soy, eggs, citrus, and peanut butter. It is thought that sugar may have a negative effect on the immune system.(3) The bacteriology of middle ear infections has changed very little since the mid-1970's with the exception of emergence of b-lactam resistance in some strains of H. influenza and M. catarrhalis. Bacterial cultures generally yield Streptococcus pneumonia (35%), Haemophilus influenzae (25%), and Moraxella catarrhalis (10%).(4)
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