Otitis media overview
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Otitis media is an inflammation of the middle ear, or middle ear infection (the word otitis is Latin and it means “inflammation of the ear”, and media means middle). Otitis media occurs in the area between the ear drum (the end of the outer ear) and the inner ear, including a duct known as the Eustachian tube. It is one of the two categories of ear inflammation that can underly what is commonly called an earache, the other being otitis externa. Diseases other than ear infections can also cause ear pain, including cancers of any structure that shares nerve supply with the ear. Otitis media is very common in childhood, with the average toddler having two to three episodes a year, almost always accompanied by a viral upper respiratory infection(URI), mostly the common cold. The rhinoviruses (nose viruses) that cause the common cold infect the Eustachian tube that goes from the back of the nose to the middle ear, causing swelling and compromise of pressure equalization, which is the normal function of the tube. In general, the more severe and prolonged the compromise of Eustachian tube function, the more severe the consequences are to the middle ear and its delicate structures. If a person is born with poor Eustachian tube function, this greatly increases the likelihood of more frequent and severe episodes of otitis media. Progression to chronic otitis media is much more common in this group of people, who often have a family history of middle ear disease.
Classification
Otitis media can be classified into many variants on the basis of etiology, duration, symptomatology, physical findings, and degree of severity. The terminology is sometimes confusing because of multiple terms being used to describe the same condition.
Causes
For each ear, a eustachian tube runs from the middle ear to the back of the throat. This tube drains fluid that is normally made in the middle ear. If the eustachian tube becomes blocked, fluid can build up. When this happens, germs such as bacteria and viruses can multiply and cause an infection. Ear infections are common in infants and children, in part because the eustachian tubes become easily clogged. Ear infections may also occur in adults, although they are less common than in children.
Risk Factors
Children below the age of seven years are much more prone to otitis media since the Eustachian tube is shorter and at more of a horizontal angle than in the adult ear. They also have not developed the same resistance to viruses and bacteria as adults. Numerous studies have correlated the incidence of acute otitis media in children with various factors such as nursing in infancy, bottle feeding when supine, parental smoking, diet, allergies and automobile emissions; but the most obvious weakness of such studies is the inability to control the variable of exposure to viral agents during the studies. One must also keep in mind that correlation does not establish causation. Breastfeeding for the first twelve months of life is associated with a reduction in the number and duration of all otitis media infections.[1]
Treatment
Primary Prevention
Specific prevention strategies applicable to all infants and children such as immunization against viral respiratory infections or specifically against the bacteria that cause otitis media are not currently available. Nevertheless, it is known that children who are cared for in group settings, as well as children who live with adults who smoke cigarettes, have more ear infections. Therefore, a child who is prone to otitis media should avoid contact with sick playmates and environmental tobacco smoke. Infants who nurse from a bottle while lying down also appear to develop otitis media more frequently. Children who have been breast-fed often have fewer episodes of otitis media. Research has shown that cold and allergy medications such as antihistamines and decongestants are not helpful in preventing ear infections. The best hope for avoiding ear infections is the development of vaccines against the bacteria that most often cause otitis media. Scientists are currently developing vaccines that show promise in preventing otitis media. Additional clinical research must be completed to ensure their effectiveness and safety.