Otitis media

OVERVIEW: What every practitioner needs to know

Are you sure your patient has otitis media? What should you expect to find?

• Acute otitis media (AOM) is diagnosed based on three criteria:

  Onset of acute illness including nonspecific signs of illness (fever, irritability, headache, anorexia, vomiting, and diarrhea) and specific signs (ear pain, otorrhea, hearing impairment, tinnitus, and nystagmus)

  Fluid in the middle ear defined by bulging of the tympanic membrane, decreased mobility of the tympanic membrane or observation of an air fluid level

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  Inflammation of the tympanic membrane

• If appropriately treated with an antibiotic, sterile middle ear fluid may persist for weeks to months after each episode of AOM and is part of the initial disease and not a new episode of AOM.

• Observation of inflammation of the tympanic membrane and identification of middle ear effusion are the keys to diagnosis of AOM.

How did the patient develop otitis media? What was the primary source from which the infection spread?

• AOM occurs as a result of the following sequence: congestion of the mucosa of the upper respiratory tract usually due to a viral infection; swelling of the mucosa of the Eustachian tube (which connects the posterior nasopharynx with the middle ear space); obstruction of the tube at its narrowest section, the isthmus; accumulation secretions that are constantly formed by the middle ear mucosa behind the Eustachian tube obstruction; and, if viral or bacterial pathogens are present, inflammation of the middle ear mucosa and tympanic membrane and development of purulent middle ear fluid.

• AOM occurs at all ages but attack rates are highest during the first 3years of life. By 3 years of age, a majority of children have had at least one episode of AOM. The age of the first episode of AOM signals a child who is likely to be susceptible to recurrent AOM. Children who are breast fed have fewer episodes of AOM than those who are bottle fed. Although AOM is infrequent in adults, the microbiology and treatment are the same. Males are more frequently affected than females. Severe and recurrent disease has been identified in certain racial and ethnic groups including Native Americans, Alaskan and Canadian Eskimos, and Australian aboriginal populations. The severity of disease in these groups may be due to climate extremes, a genetic susceptibility, or the consequences of poverty including crowding, poor hygiene, and decreased access to medical care.

Which individuals are at greater risk of developing otitis media?

• Anatomic or physiologic defects including cleft palate or other craniofacial abnormalities are associated with recurrent episodes of AOM. Children with immunodeficiencies such as chronic granulomatous disease or human immunodeficiency virus (HIV) infection may have recurrent and severe AOM as the initial or frequent sign of the underlying pathology. A genetic predisposition to severe and recurrent AOM has been identified in children born into families with siblings and parents who have a history of middle ear disease. In addition, certain racial and ethnic groups have are particularly affected by middle ear disease and its complications (see above). Infants in group day care are exposed to peers who come to the program with contributions of respiratory infections from each household; the result is up to eight episodes of respiratory infections—including AOM—per year for each of the first 3 years of life.

• Anatomic, physiologic, and immunologic defects are associated with recurrent AOM. Among healthy children, genetic susceptibility and environmental exposure to respiratory agents are the key risk factors for severe and recurrent AOM.

Beware: there are other diseases that can mimic disease otitis media:

• Otalgia or ear pain can be caused by otitis externa, a foreign body in the external ear canal or referred pain from dental disease. Middle ear effusion may result from barotrauma or allergy and be accompanied by hearing impairment.

What laboratory studies should you order and what should you expect to find?

Results consistent with the diagnosis

• Accurate clinicial diagnosis is sufficient for diagnosis of AOM. Other laboratory tests such as white blood cell (WBC) count are neither sensitive nor specific for diagnosis of AOM. If the patient is systemically ill, cultures of blood should be considered. If there is purulent drainage in the external canal, careful cleansing of the canal and culture of the pus as it emerges from the tympanic membrane perforation provides specific information about the pathogen associated with the episode of AOM.

Results that confirm the diagnosis

• Blood cultures

• Other fluid cultures, polymerase chain reaction (PCR) assays, etc.

What imaging studies will be helpful in making or excluding the diagnosis of otitis media?

• Imaging studies of patients with AOM are warranted only if there is concern for complications of the middle ear disease such as mastoiditis, petrositis, labyrinthitis, or brain abscess or meningitis.

What consult service or services would be helpful for making the diagnosis and assisting with treatment?

• The patient with severe or recurrent disease may require consultation with an otolaryngologist. In selected children or adults, placement of tympanostomy tubes may be of value in reducing the incidence of disease and decreasing time of middle ear effusion. In a rare circumstance, severe and recurrent AOM may identify a congenital or acquired immune deficiency. Other signs of recurrent infection are usually present in such patients which prompt consultation with an immunologist.

If you decide the patient has otitis media, what therapies should you initiate immediately?

• The decision to treat AOM with an antimicrobial drug is based on the age of the patient and the certainty of diagnosis. All patients with AOM do not benefit from antimicrobial agents since many episodes of AOM are due to viral agents and some episodes of bacterial AOM respond without use of antimicrobial drugs. Infants aged less than 2 years with a certain diagnosis of AOM should be treated. Some children aged more than 2 years with an uncertain diagnosis of AOM or mild disease can be managed with observation and without antimicrobial drugs. If the disease persists or becomes more severe antimicrobial agents can then be provided.

• Seventeen antimicrobial drugs (16 oral and one parenteral preparation, ceftriaxone) have been approved for treatment of AOM. In addition, two otic preparations (ofloxacin otic and ciprofloxacin—dexamethasone otic) also are available for treatmet of AOM with otorrhea in children with tympanostomy tubes in place or tympanic membrane perforation.

Key principles of therapy

1. Anti-infective agents

The microbiology of AOM has been so consistent in identifying the pneumococcus and Haemophilus influenzae as the usual agents of AOM that choice of antimicrobial drugs can be based on the assumption of providing coverage for those two agents. Amoxicillin is the drug of choice for initial therapy of AOM. If the patient has severe otalgia or a temperature greater than 39°C, amoxicillin-clavulanate should be considered to cover β-lactamase producing H. influenzae.

If I am not sure what pathogen is causing the infection, what anti-infective should I order?

Treatment options for otitis media are summarized in Table I.