Ear Infections (Otitis Media)

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Ear Infections (Otitis Media)

Introduction

Disease History, Characteristics, and Transmission

Scope and Distribution

Treatment and Prevention

Impacts and Issues

BIBLIOGRAPHY

Introduction

Otitis media is a recurring bacterial or, occasionally, viral, infection of the middle ear. The bacteria most commonly involved are Streptococcus pneumoniae, a type of Haemophilus influenzae, and Moraxella catarrhalis.

Disease History, Characteristics, and Transmission

The human ear is composed of three parts—the external or outer ear, the middle ear, and the inner ear. The outer ear is the visible portion that lies outside of the skull. It functions as a sound trap to route sound waves via a canal to the middle ear. Separating the outer and middle ear is the tympanic membrane or eardrum. In the middle ear, an arrangement of three bone spasses the sound vibrations to nerve cells that form the inner ear. The eustachian tube connects the middle portion of the ear to the nasal cavity and throat. Normally the eustachian tube acts to equalize the pressure on the two sides of the eardrum. However, when the inflammation associated with otitis media affects the eardrum, the pressure difference on either side of the eardrum can become so great that the eardrum ruptures, a painful complication.

There are several different kinds of otitis media. One type, called acute otitis media, tends to be associated with a runny or stuffy nose, and is triggered when the eustachian tube becomes blocked during the upper respiratory infection. In addition to inflammation, pus and fluid accumulate in the middle ear. The infection can also be associated with fever and irritable behavior. Other symptoms include interrupted sleep, tugging at the effected ear, and loss of balance due to the ear blockage. The acute infection tends to be of short duration.

An ear infection that does not display symptoms, including fever and irritable behavior, is known as otitis media with effusion (the infection was known as serous or secretory otitis media). Often, after the acute version of the infection, otitis media with effusion can last longer.

If the infection lasts longer than several weeks, it is referred to as chronic otitis media. The chronic form can involve bacteria growths that have become colonized, or well established in the ear. These growths are often present as surface-adherent, polysaccharide (slime)-enclosed communities called biofilms. Antibiotic treatment will kill some of the bacteria and lessen the infection. However, bacteria deeper within the biofilm survive and can be the cause of a future infection. This is the reason that chronic otitis media can persist for years.

WORDS TO KNOW

ANTIBIOTIC RESISTANCE: The ability of bacteria to resist the actions of antibiotic drugs.

BIOFILM: Biofilms are populations of microorganisms that form following the adhesion of bacteria, algae, yeast, or fungi to a surface. These surface growths can be found in natural settings such as on rocks in streams, and in infections such as can occur on catheters. Microorganisms can colonize living and inert natural and synthetic surfaces.

COLONIZATION: Colonization is the process of occupation and increase in number of microorganisms at a specific site.

Scope and Distribution

In humans, episodes of otitis media typically can begin as early as a few months of age. It is a common childhood ailment. Less frequently, the infection occurs in adults. More than 10 million children visit a doctor for treatment of ear infections each year in the United States. As children grow older and the structure of the ear changes, the frequency and incidence of ear infections usually drop. Specifically, as children mature, the eustachian tube becomes more slanted from inside to outside, which allows fluid to drain more easily. In the earlier years of childhood, the eustachian tube can have a more horizontal orientation or can even slant more towards the inside of the ear, which impedes fluid drainage and encourages the development of frequent infections.

Treatment and Prevention

Treatment of otitis media can involve decongestants or antihistamines to help clear the blocked eustachian tube and antibiotics if the bacteria are the cause of the infection (antibiotics are not effective against viruses). Even with antibiotic treatment an infection may take weeks or months to completely clear, as bacteria within the biofilm are progressively killed. For this reason, the full course of antibiotic therapy must be followed. Stopping treatment early, because symptoms diminish or disappear, may allow bacteria to survive. These survivors may develop resistance to the antibiotic that was used, making treatment of the next infection more difficult.

When a chronic infection does not respond to treatment, more drastic action may be necessary. Surgery to install a plastic drainage tube—a procedure called myringotomy—may be performed. Less frequently, surgical removal of infected, swollen adenoids or tonsils may be done. Myringotomy is a common childhood surgery in the United States. The tube is removed later, as the maturing eustachian tube more naturally drains fluid from the middle ear.

Research concerning the nature of the biofilms formed by bacteria in otitis media is underway. It is unclear whether there are some distinguishing features about the bacteria that make them more likely to cause an infection. If so, identification of the genetic factors involved is important, since it could lead to better strategies to deal with an infection or, perhaps, help in the development of preventive measures. Current research also aims to discover why some children are more prone to ear infections than other children and to develop more accurate and rapid means of diagnosing otitis media.

Impacts and Issues

Otitis media is the number one reason that parents bring a sick child to a physician. Medical costs and lost wages due to otitis media in the United States alone are estimated to be almost $5 billion per year. The ultimate challenge for researchers in otitis media is to create a vaccine for infants that would prevent the first acute otitis media infection. Several vaccine candidates are at different stages in the testing and approval process, from animal testing to first-phase clinical trials.

OTITIS MEDIA VS. SWIMMER'S EAR

The The Centers for Disease Control and Prevention (CDC), Division of Parasitic Diseases is careful to warn the public that middle ear infection is not the same as Swimmer's Ear. The CDC states, “If you can wiggle the outer ear without pain or discomfort then your ear infection is probably not Swimmer's Ear.”

SOURCE: The Centers for Disease Control and Prevention (CDC), Division of Parasitic Diseases

Otitis media can be a serious infection, producing chronic diminished hearing ability or permanent hearing loss. Hearing impairment in a child during the years of language acquisition can result in learning and socialization delays, and speech disabilities.

As with other chronic bacterial infections, the symptoms associated with chronic ear infections can be less severe and uncomfortable than those of the acute form of the infection. Chronic infections may thus escape detection for long periods of time, potentially leading to serious complications, including permanent damage to the ear and hearing loss.

See AlsoAntibiotic Resistance; Swimmer's Ear and Swimmer's Itch (Cercarial Dermatitis).

BIBLIOGRAPHY

Books

Friedman, Ellen M., and James P. Barassi. My Ear Hurts!: A Complete Guide to Understanding and Treating Your Child's Ear Infections. Darby, PA: Diane Publishing Company, 2004.

Schmidt, Michael A. Childhood Ear Infections: A Parent's Guide to Alternative Treatments. Berkeley, CA: North Atlantic Books, 2004.

Periodicals

Jackson, Patricia L. “Healthy People 2010 Objective: Reduce Number and Frequency of Courses of Antibiotics for Ear Infections in Young Children.” Pediatric Nursing 27 (2000): 591–595.

Web Sites

National Institute on Deafness and Other Communication Disorders. “Otitis Media (Ear Infection).” July 2002. <http://www.nidcd.nih.gov/health/hearing/otitism.asp> (accessed April 10, 2007).

Brian Hoyle

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