Mastoiditis

Definition

Otitis media is an infection of the middle ear space, behind the eardrum (tympanic membrane).

Description

A little knowledge of the basic anatomy of the middle ear will be helpful for understanding the development of otitis media. The external ear canal is that tube which leads from the outside opening of the ear to the structure called the tympanic membrane. Behind the tympanic membrane is the space called the middle ear. Within the middle ear are three tiny bones, called ossicles. Sound (in the form of vibration) causes movement in the eardrum, and then the ossicles. The ossicles transmit the sound to a structure within the inner ear, which sends it to the brain for processing.

The nasopharynx is that passageway behind the nose which takes inhaled air into the breathing tubes leading to the lungs. The eustachian tube is a canal which runs between the middle ear and the nasopharynx. One of the functions of the eustachian tube is to keep the air pressure in the middle ear equal to that outside. This allows the eardrum and ossicles to vibrate appropriately, so that hearing is normal.

By age three, almost 85% of all children will have had otitis media at least once. Babies and children between the ages of six months and six years are most likely to develop otitis media. Children at higher risk factors for otitis media include boys, children from poor families, Native Americans, Native Alaskans, children born with cleft palate or other defects of the structures of the head and face, and children with Down syndrome. Exposure to cigarette smoke significantly increases the risk of otitis media; as well as other problems affecting the respiratory system. Also, children who enter daycare at an early age have more upper respiratory infections (URIs or colds), and thus more cases of otitis media. The most usual times of year for otitis media to strike are in winter and early spring (the same times URIs are most common).

Otitis media is an important problem, because it often results in fluid accumulation within the middle ear (effusion). The effusion can last for weeks to months. Effusion within the middle ear can cause significant hearing impairment. When such hearing impairment occurs in a young child, it may interfere with the development of normal speech.

Causes & symptoms

The first thing necessary for the development of otitis media is exposure to an organism capable of causing the infection. These include a variety of viruses, as well as such bacteria as Streptococcus pneumoniae (causes about 35% of all acute ear infections), Haemophilus influenzae (causes about 23% of all acute ear infections), or Moraxella catarrhalis (causes about 14% of all acute ear infections).

There are other factors which make the development of an ear infection more likely. Because the eustachian tube has a more horizontal orientation and is considerably shorter in early childhood, material from the nasopharynx (including infection-causing organisms) is better able to reach the middle ear. Children also have a lot of lymph tissue (commonly called the adenoids) in the area of the eustachian tube. These adenoids may enlarge with repeated respiratory tract infections (colds), ultimately blocking the eustachian tubes. When the eustachian tube is blocked, the middle ear is more likely to fill with fluid. This fluid, then, increases the risk of infection, and the risk of hearing loss and delayed speech development.

Most cases of acute otitis media occur during the course of a URI. Symptoms include fever, ear pain, and problems with hearing. Babies may have difficulty feeding. When significant fluid is present within the middle ear, pain may increase depending on position. Lying down may cause an increase in painful pressure within the middle ear, so that babies may fuss if not held upright. If the fluid build-up behind the eardrum is sufficient, the eardrum may develop a hole (perforate), causing bloody fluid or greenish-yellow pus to drip from the ear. Although pain may be significant leading up to such a perforation, the pain is usually relieved by the reduction of pressure brought on by a perforation.

Diagnosis

Diagnosis is usually made simply by looking at the eardrum through a special lighted instrument called an otoscope. The eardrum will appear red and swollen, and may appear either abnormally drawn inward, or bulging outward. Under normal conditions, the ossicles create a particular pattern on the eardrum, referred to as "landmarks." These landmarks may be obscured. Normally, the light from the otoscope reflects off of the eardrum in a characteristic fashion. This is called the "cone of light." In an infection, this cone of light may be shifted or absent.

A special attachment to the otoscope allows a puff of air to be blown lightly into the ear. Normally, this should cause movement of the eardrum. In an infection, or when there if fluid behind the eardrum, this movement may be decreased or absent.

If fluid or pus is draining from the ear, it can be collected. This sample can then be processed in a laboratory to allow any organisms present to multiply sufficiently (cultured) to permit the organisms to be viewed under a microscope and identified.

Treatment

Antibiotics are the treatment of choice for ear infections. Different antibiotics are used depending on the type of bacteria most likely to be causing the infection. This decision involves knowledge of the types of antibiotics that have worked on other ear infections occurring within a particular community at a particular time. Options include sulfa-based antibiotics, as well as a variety of penicillins and cephalosporins.

Some controversy exists regarding whether overuse of antibiotics is actually contributing to the development of bacteria, which may evolve and become able to avoid being killed by antibiotics. Research is being done to try to help determine whether there may be some ear infections which would resolve without antibiotic treatment. In the meantime, the classic treatment of an ear infection continues to involve a 7-10 day course of antibiotic medication.

Some medical practitioners prescribe the use of special nosedrops, decongestants, or antihistamines to improve the functioning of the eustachian tube.

In a few rare cases, a procedure to drain the middle ear of pus may be performed. This procedure is called myringotomy.

Alternative treatment

Some practitioners believe that food allergies may increase the risk of ear infections, and they suggest eliminating suspected food allergens from the diet. The top food allergens are wheat, dairy products, corn, peanuts, citrus fruits, and eggs. Elimination of sugar and sugar products can allow the immune system to work more effectively. A number of herbal treatments have been recommended, including ear drops made with goldenseal (Hydrastis canadensis), mullein (Verbascum thapsus), St. John's wort (Hypericum perforatum), and echinacea (Echinacea spp.). Among the herbs often recommended for oral treatment of otitis media are echinacea and cleavers (Galium aparine), or black cohosh (Cimicifuga racemosa) and ginkgo (Ginkgo biloba). Homeopathic remedies that may be prescribed include aconite (Acontium napellus), Ferrum phosphoricum, belladonna, chamomile, Lycopodium, pulsatilla (Pulsatilla nigricans), or silica. Craniosacral therapy uses gentle manipulation of the bones of the skull to relieve pressure, and improve eustachian tube function.

Prognosis

With treatment, the prognosis for acute otitis media is very good. However, long-lasting accumulations of fluid within the middle ear are a risk both for difficulties with hearing and speech, and for the repeated development of ear infections. Furthermore, without treatment, otitis media can lead to an infection within the nearby mastoid bone, called mastoiditis.

Prevention

Although otitis media seems somewhat inevitable in childhood, some measures can be taken to decrease the chance of repeated infections and fluid accumulation. Breastfeeding provides some protection against URIs, which in turn protects against the development of otitis media. If a child is bottle-fed, parents should be advised to feed him or her upright, rather than allowing the baby to lie down with the bottle. General good hygiene practices (especially handwashing) help to decrease the number of upper respiratory infections in a household or daycare center.

After a child has completed treatment for otitis media, a return visit to the practitioner should be scheduled. This visit should occur after the antibiotic has been completed, and allows the practitioner to evaluate the patient for the persistent presence of fluid within the middle ear. In children who have a problem with recurrent otitis media, a small daily dose of an antibiotic may prevent repeated full attacks of otitis media. In children who have persistent fluid, a procedure to place tiny tubes within the eardrum may help equalize pressure between the middle ear and the outside, thus preventing further fluid accumulation.

Key Terms

Adenoid

A collection of lymph tissue located in the nasopharynx.

Effusion

A collection of fluid which has leaked out into some body cavity or tissue.

Eustachian tube

A small tube which runs between the middle ear space and the nasopharynx.

Nasopharynx

The part of the airway into which the nose leads.

Ossicles

Tiny bones located within the middle ear which are responsible for conveying the vibrations of sound through to the inner ear.

Perforation

A hole.

Further Reading

For Your Information

Books

• Duran, Marlene, et al. "Infections of the Upper Respiratory Tract." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. 14th ed. New York: McGraw-Hill, 1998.
• "Otitis Media and its Complications." In Nelson Textbook of Pediatrics, edited by Richard Behrman. Philadelphia: W.B. Saunders Co., 1996.
• Ray, C. George. "Eye, Ear, and Sinus Infections." In Sherris Medical Microbiology: An Introduction to Infectious Diseases, edited by Kenneth J. Ryan. Norwalk, CT: Appleton and Lange, 1994.

  Periodicals

• Berman, Stephen. "Otitis Media in Children." The New England Journal of Medicine 332(June 8, 1995): 1560+.
• Daly, Kathleen A., et al. "Knowledge and Attitudes About Otitis Media Risk: Implications for Prevention." Pediatrics 100(December 1997): 931+.
• Dowell, Scott F., et al. "Otitis Media: Principles of Judicious Use of Antimicrobial Agents." Pediatrics 101(January 1998): 165+.
• Lary, Marvis J. "Otitis Media: Current Concepts." Physician Assistant 21(July 1997): 26+.
• Pizzuto, Michael. "Let's Hear A Little More About Antibiotics and Otitis Media." Consultant 37(March 1997): 502+.

  Organizations

• American Academy of Otolaryngology-Head and Neck Surgery, Inc. One Prince Street, Alexandria VA 22314-3357. (703) 836-4444.

Gale Encyclopedia of Medicine. Gale Research, 1999.