Family Practice Clerkship
Summer 2005
Introduction
Although tympanometry is often performed in evaluating AOM and differentiating it from OME, an accurate and precise diagnosis can be achieved by a physical examination with a thorough history with or without pneumatic otoscopy (Chamberlain, RL. Personal communication. March 2004). The most important aspect of the differential diagnosis comes from the history, whether there has been acute onset with associated infection or whether the present state is associated with a chronic matter. Furthermore, neither tympanometry nor pneumascopy are in wide use amongst UK GPs (SIGN, 2003).
Definitions
According to SIGN (Scottish Intercollegiate Guidelines Network), otitis media refers to both the acute process marked by active inflammation, labeled acute otitis media (AOM), and the presence of effusion in the middle ear without active pathogenesis, labeled otitis media with
effusion (OME). The term middle ear effusion (MEE) may be used to replace the somewhat misleading term otitis media, since effusion is present in both conditions, AOM and OME,
respectively (JHU, 2000).
Background
Otitis media (AOM and OME) is greatly underrepresented in the literature, and the studies available are poorly designed with innate flaws and arbitrary guidelines and exclusion-inclusion principles (SIGN, 2004; JHU, 2000).
Etiology
Of contemporary import in the etiology of AOM are s. pneumoniae (40%), H. influenzae (25-30%), Moraxella catarrhalis (10-20%), A. streptococci (3%), staphylococcus aureus (2%), and 1-2% by gram-negative cocci (JHU, 2000). Allergic complications are also significant in the primary development of or in associated causative factors, such as sinusitis. Viral AOM is also prevalent (30-40%), with the syncytial virus most commonly found (JHU, 2000).
The specific pathophysiology, however, is triggered by the occlusion of the eustachian tube, further inducing production of secretory epithelial cells (mucosa), compromization of mucociliary transport system, and finally the classic effusion feature, denoted as MEE and further delineated as either AOM or OME (JHU, 2000).
Incidence
Annually, the US spends an average of 5 billion and from 1993 to 1995 there were an estimated 20 million incidents of otitis media (AOM and OME) annually (JHU, 2000). In children under 5 years, AOM and OME, respectively is the most commonly diagnosed illness spectrum.
History
Over 80% of the time, a correct diagnosis comes almost entirely from the history; therefore, the clinician must take care to elicit the specific symptoms, as well as the nature of onset, whether acute or chronic.
Otoscopic Examination Findings
In otoscopy, careful attention must be placed on color, appearance or absence of landmarks, shape, and opacity. The color is normally a pearly gray; however, with AOM the color is either red or white. Normally, the landmarks the short process of the malleus, often the incus as well, the ligament attaching to the malleus, and the connical light cone reflex can be readily distinguished. In AOM, obstruction by effusion and distorted contour hinder the ability to view these landmarks, and often they are not distinguished.
The reflection of light on the tympanic membrane is normally appreciated as a triangular reflection; however in retracted (concave) or hyper-convective states, the light reflex will be appreciated as an oval or circular light pattern. Often with sever effusion, the tympanic membrane may be severely bulging or somewhat rotated; these features are most easily distinguished by noting the light pattern on the tympanic membrane. Generally, a healthy tympanic membrane is translucent, allowing the view of parts of the malleus and incus. In cases of AOM, however, opacity is a characteristic finding.
Treatment
Stemming form the ever-increasing incidence of antibiotic resistant strains of bacteria, particularly s. pneumoniae, treatment should not necessarily begin with antibiotic therapy, especially in the absence of comorbidities, such as sinusitis or lower respiratory infection. Recent UK statistics indicate delayed antibiotic therapy (72 hours after initial office visit, if child did not begin to improve) reduces the use of such agents 24% of the time (SIGN, 2004).
Symptomatic
Ibuprofen or acetaminophen given as needed for pain and reduction of fever are effective. Aural drops of benzocane and antipryine are effective in controlling pain of the tympanic membrane. In severe cases where the tympanic membrane is bulging and appears to be threatening to perforate, the option of performing a myringotomy must be seriously considered to minimize scaring and permit drainage, thus eliminating pain.
Antibiotic
The usual course with most antibiotics is 10-14 days; although, recent UK research suggests 5 days is adequate in most cases (SIGN, 2004). Antibiotic therapy usually consists of using either amoxicillin, which has a lower rate of stomach irritation, or ampicillin. Amoxicillin given 40-50 mg/ kg/ day for 5 days is adequate in low risk patients; whereas, the dose and duration is doubled in patients with increased risk of treatment failure (Rakel, 2002). Treatment options for reversing treatment failure include: amoxicillin-clavulanate, 80-90 mg/ kg/ day for 10 days; cefuroxime axetil, 80-90 mg/ kg/ day for 10 days; and ceftriaxone, IM 50 mg/ kg in a single dose (Rakel, 2002).
For patients allergic to penicillin, the following preparations should be considered when choosing antibiotic therapy: cefuroxime axetil, (under 2 years) 125 mg b.i.d. (over 2 years) 250 mg b.i.d.; trimethoprim-sulfamethoxazde, 8 mg/ kg trimethoprim and 40 mg/ kg sulfamethoxazde q. 24h in 2 doses; cefprozil, 30 mg/ kg/ in 2 doses; cefaclor 40 mg/ kg/ day in 3 doses; and cefixime, 8 mg/ kg/ day (Rakel, 2002).
While a great many cases of AOM remain undiagnosed due to a lack of symptoms, a significant minority, even with appropriate treatment, have incomplete resolution leading to OME, which can produce hearing loss. Persistent problems, defined by National Institute for Clinical Excellence (NICE), as, “more than four episodes in six months,” an in the US as “more than three episodes in six moths or more than four in twelve months,” require otorhinolaryngologic referral (SIGN, 2004). Serious complications, while rare since the advent of antibiotic therapy, can include: mastoiditis, osteomylitis, and possible infiltration into the central nervous system (Chamberlain, RL. Personal communication. March 2004). References Johns Hopkins University School of Medicine and The Institute for Johns Hopkins Nursing.: A View Through the Otoscope: Distinguishing Acute Otitis Media from Otitis Media with Effusion. Paramus: Innovative Medical Education, 2000. Pp. 3-8. Rakel, R. E.: Textbook of Family Practice. (6th ed.) Philadelphia: W. B. Saunders, 2002. Pp. 439-440. Scottish Intercollegiate Guidelines Network (SIGN): Diagnosis and Management of Childhood Otitis Media in Primary Care. Glasgow, 2004. Sections: 2-4.
