Ear Infection

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Ear infection

Definition

Otitis media is an infection of the middle ear space, which lies behind the eardrum (tympanic membrane). It is characterized by pain, dizziness , and partial loss of hearing.

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 a tube that leads from the outside opening of the ear to a 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. These are the malleus, the incus, and the stapes. Their shapes are often described as a hammer, an anvil, and a stirrup. Sound in the form of vibration causes movement in the eardrum, and then in the chain of ossicles. The ossicles transmit the sound to the cochlea within the inner ear, which sends it to the brain for processing.

The nasopharynx is the passageway behind the nose that takes inhaled air into the breathing tubes leading to the lungs. The eustachian tube is a canal that 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 equalization of the air pressure 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. It is the most common pediatric complaint. Babies and children between the ages of six months and six years are most likely to develop otitis media. Children at higher risk for otitis media include boys, children from poor families, those with allergies , 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. Babies whose first ear infection occurs prior to six months of age are more prone to chronic problems with otitis media. There also appears to be some genetic predisposition towards otitis media, which may be related to the structure and function of the area in and around the middle ear. Exposure to cigarette smoke significantly increases the risk of ear infections , as well as other problems affecting the respiratory system. In addition, children who enter daycare at an early age have more upper respiratory infections (URIs or colds), and thus more cases of otitis media. Although the ear infection itself is not contagious, the URIs that predispose children to them certainly are. The most common times of year for otitis media to strike are winter and early spring, which are the same times that URIs are most common.

Otitis media is an important medical problem, because it often results in fluid accumulation within the middle ear. This is known as otitis media with effusion (OME). 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 and language processing. A chronic effusion also increases the risk for subsequent infections, as the fluid provides a growth medium for bacteria.

In adults, acute otitis media can lead to such complications as paralysis of the facial nerves. Recovery from these complications may take from two weeks to as long as three months.

Causes & symptoms

The first precondition for the development of acute otitis media is exposure to an organism capable of causing the infection. Otitis media can be caused by either viruses or bacteria. Virus infections account for about 15% of cases. The three most common bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis. As of 2003, about 75% of ear infections caused by S. pneumoniae are reported to be resistant to penicillin.

Otitis media may also be caused by other disease organisms, including Bordetella pertussis, the causative agent of whooping cough , and Pneumocystis carinii, which often causes opportunistic infections in patients with AIDS .

There are other factors that 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 can easily reach the middle ear. Discharges from the nasopharynx include infection-causing organisms. Children also have a lot of lymph tissue, some of which makes up the adenoids, in the area of the eustachian tube. The adenoids may enlarge with repeated respiratory tract infections, ultimately blocking the eustachian tubes. When the eustachian tube is blocked, the middle ear is more likely to fill with fluid. This fluid increases the risk of infection, and the corresponding risks of hearing loss and delayed speech development.

Recent advances in gene mapping have led to the discovery of genetic factors that increase a child's susceptibility to otitis media. Researchers are hoping to develop molecular diagnostic assays that will help to identify children at risk for severe ear infections.

Most cases of acute otitis media occur during the course of a URI. Symptoms may include cold symptoms, fever , ear pain, irritability, and problems with hearing. Babies may have difficulty feeding. When significant fluid is present within the middle ear, pain can increase depending on position. Lying down may cause an increase in painful pressure within the middle ear, so that babies often fuss if not held upright. Older children sometimes complain of a full sensation in the affected ear. 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 the pain may be severe before the eardrum perforates, 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 in the course of an infection. Normally, the light from the otoscope reflects off 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 the examiner to blow a puff of air gently 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. Movement of the eardrum can also be assessed by a tympanogram. A tympanogram is a quick, painless test. If there is fluid in the middle ear, the tympanogram reading will be flat. If the middle ear is filled with air, as it is normally, the test will also show whether it is at higher or lower pressure than it should be. This measurement could be an indicator of abnormal function of the eustachian tube.

Hearing tests, or audiograms, are sometimes used to determine whether hearing loss has occurred because of infection or persistent fluid, and whether the loss is severe. A hearing screen for children old enough to describe their own hearing reliably can be performed in schools or at the pediatrician's office. More accurate testing is done in a soundproof booth by an audiologist. This method can also be modified for use with children who can't give a verbal indication that they have heard a sound, but are old enough to turn their heads to see the source of a noise.

Fluid or pus draining from the ear 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. Cultures are also used to determine the sensitivity of the organisms to specific antibiotics.

Treatment

Chiropractic

One particular chiropractic procedure, known as the endonasal technique, is thought to help the eustachian tube to open and thus improve drainage of the middle ear. The tube is sometimes blocked off due to exudates or inflammatory processes. The endonasal technique can offer significant relief from earache .

Craniosacral therapy and osteopathy

Craniosacral therapy uses gentle manipulation of the bones of the skull to relieve pressure and improve eustachian tube function. This treatment may also help the eustachian tubes to assume a position in which they can drain on their own. The pressure exerted on a baby's head during the birth process sometimes contributes to the tubes being in a position in which it is hard for them to drain. Osteopaths practice a similar gentle manipulation of the bones of a child's head. One osteopathic study of children from kindergarten through third grade in a Missouri school district found a direct correlation between abnormal head shape at birth and susceptibility to otitis media during the early elementary school years. As of 2003 there are pediatric osteopaths who specialize in cranial work.

Herbal therapy

A number of herbal treatments for otitis media have been recommended, including eardrops made with goldenseal (Hydrastis canadensis ), mullein (Verbascum thapsus ), St. John's wort (Hypericum perforatum ), and echinacea (Echinacea spp.). Tinctures of echinacea, thyme (Thymus vulgaris ), and elderflower (Sambucus nigra ) are often recommended for oral treatment of otitis media due to chronic congestion. Warm garlic oil can be instilled directly into the ear. Steam inhalation infused with eucalyptus or chamomile may reduce the congestion of the URIs that often accompany otitis media.

Homeopathy

Homeopathic remedies that may be prescribed for middle ear infections include aconite, ferrum phosphoricum, belladonna , chamomilla, lycopodium, pulsatilla , or silica .

Nutrition

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. Other nutritionists have noted that children who were breastfed as babies are less susceptible to ear infections.

Acupuncture

Acupuncture can help to reestablish a normal flow of fluids within the head. This form of treatment may also enhance the immune system.

Allopathic treatment

Medications

Antibiotics are the treatment of choice for acute otitis media (AOM). 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, cephalosporins, and others. The patient's sensitivity to certain medications, as well as previously demonstrated resistant strains, also contributes to the choice of antibiotic. As of 2003, an 0.3% topical solution of ofloxacin has been recommended as a more effective medication than other oral or topical antibiotics.

Following a course of antibiotic treatment, approximately 40% of children will continue to have fluid behind the eardrum, resulting in otitis media with effusion (OME). The eardrum is no longer red or infected. The fluid may take weeks to months to resolve. Generally, it is safe to allow this condition to continue with observation for up to 12 weeks. At that time, hearing should be tested. If hearing loss is insignificant or only in one ear, observation can continue for up to a total of 4–6 months, at which time placement of ventilation tubes in the eardrum is often recommended. The tube functions as an accessory eustachian tube until it falls out. If hearing loss is significantly affecting both ears at any time after six weeks from diagnosis of OME, antibiotic treatment or tube placement should be considered.

The overuse of antibiotics is contributing to some strains of bacteria—particularly S. pneumoniae —developing resistance and becoming more difficult to treat. Research is being done to try to help determine whether there may be some ear infections that would resolve without antibiotic treatment. One pediatrician has suggested some changes in usage of antibiotics for otitis media. He describes five factors to use to determine whether antibiotic treatment can be limited to five days or perhaps avoided altogether. The factors to consider are the age of the child; time of year; severity of the infection; frequency of infection; and rapidity of response to antibiotics. Generally, otitis media clears more readily when it occurs in an older child, in the summer, and causes relatively mild symptoms in a child who has not experienced frequent infections in the past. Given these factors, it may be possible to avoid antibiotic use. The patient must be monitored to be sure the infection clears without complication. If antibiotic treatment is initiated and the infection clears quickly, a five-day course of medication may be all that's needed.

Whether or not antibiotics are used, such pain relievers as Tylenol or Motrin can be very helpful in reducing the pain and inflammation associated with otitis media.

The use of decongestants and antihistamines does not appear to shorten the course of infection.

Surgery

In a few rare cases, a surgical perforation to drain the middle ear of pus may be performed. This procedure is called a myringotomy. The hole created by the myringotomy generally heals itself in about a week. In 2002 a new minimally invasive procedure was introduced that uses a laser to perform the myringotomy. It can be performed in the doctor's office and heals more rapidly than the standard myringotomy.

Although some doctors have recommended removing the adenoids to prevent recurrent otitis media in young children, recent studies indicate that surgical removal of the adenoids does not appear to offer any advantages over a myringotomy as a preventive measure.

Expected results

With treatment, the prognosis for acute otitis media is very good. Long-lasting accumulations of fluid within the middle ear, however, place the patient at risk both for difficulties with hearing and speech, and for the repeated development of ear infections. Furthermore, without treatment, otitis media occasionally leads to serious complications, including an infection within the nearby mastoid bone, called mastoiditis.

Prevention

Although otitis media seems 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 hand washing) help to decrease the number of upper respiratory infections in a household or daycare center. Hand sanitizers are preferable to antibacterial soaps, which may contribute to bacterial resistance.

The use of pacifiers should be avoided or limited. They may act as fomites, particularly in a daycare setting. In children who are more susceptible to otitis media, pacifier use can increase by as much as 50% the number of ear infections experienced.

Two vaccines can prevent otitis media associated with certain strains of bacteria. One is designed to prevent meningitis and other diseases, including otitis media, that result from infection with Haemophilus influenzae type B. Another is a vaccine against Streptococcus pneumoniae, a very common cause of otitis media. Children who are at high risk or have had severe or chronic infections may be good candidates for these vaccines; in fact, a recent consensus report among pediatricians recommended routine administration of the pneumococcal conjugate vaccine to children younger than two years, as well as those at high risk for AOM. Parents should consult a healthcare provider concerning the advisability of this treatment.

Another vaccine that appears to lower the risk of AOM in children is the intranasal vaccine that was recently introduced for preventing influenza . Although the flu vaccine was not developed to prevent AOM directly, one team of researchers found that children who were given the vaccine before the start of flu season were 43% less likely to develop AOM than children who were not vaccinated.

As of early 2003, there is no vaccine effective against M. catarrhalis. Researchers are working on developing such a vaccine, as well as a tribacterial vaccine that would be effective against all three pathogens that commonly cause otitis media.

A nutrition-based approach to preventive treatment is undergoing clinical trials as of late 2002. This treatment involves giving children a dietary supplement of lemon-flavored cod liver oil plus a multivitamin formula containing selenium . The pilot study found that children receiving the supplement had fewer cases of otitis media, and that those who did develop it recovered with a shorter course of antibiotic treatment than children who were not receiving the supplement.

After a child has completed treatment for otitis media, a return visit to the practitioner should be scheduled. This visit should occur after the course of antibiotic has been completed. It 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 frequent bouts of otitis media or persistent fluid, a procedure to place ventilation tubes within the eardrum may help to equalize pressure between the middle ear and the outside, thus preventing further fluid accumulation.

Resources

BOOKS

Duran, Marlene, et al. "Infections of the Upper Respiratory Tract." In Harrison's Principles of Internal Medicine, 14th ed., edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1998.

"Otitis Media and its Complications." In Nelson's Textbook of Pediatrics, edited by Richard Behrman. Philadelphia: W.B. Saunders Co., 1996.

Pelletier, Kenneth R., MD. The Best Alternative Medicine, Part I: Chiropractic and Osteopathy. New York: Simon & Schuster, 2002.

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

Abes, G., N. Espallardo, M. Tong, et al. "A Systematic Review of the Effectiveness of Ofloxacin Otic Solution for the Treatment of Suppurative Otitis Media." ORL 65 (March-April 2003): 106–116.

Bucknam, J. A., and P. C. Weber. "Laser Assisted Myringotomy for Otitis Media with Effusion in Children." ORL-Head and Neck Nursing 20 (Summer 2002): 11-13.

Cripps, A. W., and J. Kyd. "Bacterial Otitis Media: Current Vaccine Development Strategies." Immunology and Cell Biology 81 (February 2003): 46–51.

Decherd, M. E., R. W. Deskin, J. L. Rowen, and M. B. Brindley. "Bordetella pertussis Causing Otitis Media: A Case Report." Laryngoscope 113 (February 2003): 226–227.

Goodwin, J. H., and J. C. Post. "The Genetics of Otitis Media." Current Allergy and Asthma Reports 2 (July 2002): 304-308.

Hoberman, A., C. D. Marchant, S. L. Kaplan, and S. Feldman. "Treatment of Acute Otitis Media Consensus Recommendations." Clinical Pediatrics 41 (July-August 2002): 373-390.

Linday, L. A., J. N. Dolitsky, R. D. Shindledecker, and C. E. Pippinger. "Lemon-Flavored Cod Liver Oil and a Multivitamin-Mineral Supplement for the Secondary Prevention of Otitis Media in Young Children: Pilot Research." Annals of Otology, Rhinology, and Laryngology 111 (July 2002): 642-652.

Marchisio, P., R. Cavagna, B. Maspes, et al. "Efficacy of Intranasal Virosomal Influenza Vaccine in the Prevention of Recurrent Acute Otitis Media in Children." Clinical Infectious Diseases 35 (July 15, 2002): 168-174.

Mattila, P. S., V. P. Joki-Erkkila, T. Kilpi, et al. "Prevention of Otitis Media by Adenoidectomy in Children Younger Than 2 Years." Archives of Otolaryngology—Head and Neck Surgery 129 (February 2003): 163–168.

Menger, D. J., and R. G. van den Berg. "Pneumocystis carinii Infection of the Middle Ear and External Auditory Canal. Report of a Case and Review of the Literature." ORL 65 (January-February 2003): 49–51.

Redaelli de Zinis, L. O., P. Gamba, and C. Balzanelli. "Acute Otitis Media and Facial Nerve Paralysis in Adults." Otology and Neurotology 24 (January 2003): 113–117.

Weiner, R., and P. J. Collison. "Middle Ear Pathogens in Otitis Prone Children." South Dakota Journal of Medicine 56 (March 2003): 103–107.