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Acute Otitis Media: Update on Diagnosis and Antibiotic Choices

Acute Otitis Media: Update on Diagnosis and Antibiotic Choices

Among American children, acute otitis media (AOM) is the most common bacterial infection treated with antibiotics. Rising rates of antibacterial resistance coupled with the increasing cost of antibiotics have focused attention on the need to prescribe these agents judiciously. Recently, the American Academy of Pediatrics issued recommendations on the diagnosis and management of uncomplicated AOM in children aged 2 months to 12 years.1 These guidelines apply only to otherwise healthy children who have no underlying conditions that may alter the natural course of AOM, such as cleft palate, Down syndrome, immunodeficiencies, or the presence of cochlear implants. Also excluded are children who have recurrent AOM or AOM with underlying chronic otitis media with effusion (OME). Highlights of the guidelines are presented here.

DIAGNOSTIC POINTERS

The diagnosis of AOM rests on:

•A history of acute onset.
•Evidence of a middle-ear effusion (MEE). 
•Signs and symptoms of middle-ear inflammation (Table 1).

History. Children with AOM generally present with a history of rapid onset of symptoms, including otalgia, irritability (in an infant or toddler), otorrhea, and/or fever. However, these symptoms—except for otorrhea—are nonspecific and often overlap with the symptoms of an uncomplicated upper respiratory tract viral infection. Other symptoms of an upper respiratory tract viral infection, such as cough and nasal discharge or stuffiness, often precede or accompany AOM and are also nonspecific. Thus, clinical history alone is a weak indicator of AOM, especially in younger children.

Otoscopic findings. Identification of an MEE and inflammatory changes in the tympanic membrane is essential for making the diagnosis. These findings are usually detected by pneumatic otoscopy, although pneumatic otoscopy can be supplemented with tympanometry or acoustic reflectometry. MEE can also be demonstrated directly by tympanocentesis or by the presence of fluid in the external auditory canal as a result of tympanic membrane perforation. Otoscopic findings that signal an MEE and inflammation have been well defined. Fullness or bulging of the tympanic membrane has the highest predictive value for an MEE (Figure).

Reduced or absent mobility of the tympanic membrane also suggests the presence of fluid in the middle ear. Opacification or cloudiness of the tympanic membrane that results from edema rather than from scarring is also consistent with an MEE. The strongest predictor of AOM is bulging of the membrane coupled with erythema and limited or absent mobility. An uncertain diagnosis of AOM is usually attributable to an inability to confirm the presence of MEE. Contributing factors include the inability to sufficiently clear the external auditory canal of cerumen, a narrow ear canal, or inability to maintain an adequate seal for successful pneumatic otoscopy or tympanometry. Acoustic reflectometry can be helpful, because it requires no seal of the canal and can ascertain the presence of middle-ear fluid through only a small opening in the cerumen. A key challenge is to distinguish AOM from OME, which is usually not treated with antibiotics. OME is relatively asymptomatic, and pneumatic otoscopy often reveals a retracted or concave tympanic membrane.

TREATMENT
Pain management. If otalgia is present, take steps to reduce the pain and discomfort—especially during the first 24 hours of the illness— regardless of whether an antibiotic is prescribed. Acetaminophen or ibuprofen is most often used in this setting; topical agents that contain benzocaine may provide additional relief in children older than 5 years.

The case for watchful waiting. During the past 30 years, placebocontrolled trials of AOM have consistently shown that most children will improve without antibacterial therapy—and without adverse sequelae. Between 7 and 20 children must be treated with antibiotics for 1 child to derive benefit. 2-4 Twentyfour hours after the onset of illness, symptoms diminished in 61% of children whether they received placebo or an antibiotic; by the seventh day after onset, symptoms resolved in approximately 75% of children.5 A meta-analysis showed a 12.3% reduction in the clinical failure rate within 2 to 7 days of diagnosis when ampicillin or amoxicillin was prescribed, compared with the initial use of placebo or observation (number needed to treat, 8).6 The decision to observe or prescribe an antibiotic is based on the child’s age, the certainty of the diagnosis, and the severity of the illness (Table 2). Watchful waiting is appropriate only for:

References

REFERENCES:
1. Subcommittee on Management of Acute Otitis Media. Diagnosis and management of acute otitis media. Pediatrics. 2004;113:1451-1465.
2. Rosenfeld RM, Vertrees JE, Carr J, et al. Clinical efficacy of antimicrobial drugs for acute otitis media: metaanalysis of 5400 children from thirty-three randomized trials. J Pediatr. 1994;124:355-367.
3. Del Mar C, Glasziou P, Hayem M. Are antibiotics indicated as initial treatment for children with acute otitis media? A meta-analysis. BMJ.. 1997;314: 1526-1529.
4. Glasziou PP, Del Mar CB, Hayem M, Sanders SL. Antibiotics for acute otitis media in children. Cochrane Database Syst Rev. 2000;(4):CD000219.
5. Rosenfeld RM, Kay D. Natural history of untreated otitis media. In: Rosenfeld RM, Bluestone CD, eds. Evidence-Based Otitis Media. 2nd ed. Hamilton, Ontario: BC Decker Inc; 2003:180-198.
6. Appelman CL, Van Balen FA, Van de Lisdonk EH, et al. Otitis media acuta. NHG-standaard (eerste herziening) [in Dutch]. ,i>Huisarts Wet.,/i> 1999;42: 362-366.
7. Clements DA, Langdon L, Bland C, Walter E. Influenza A vaccine decreases the incidence of otitis media in 6- to 30-month-old children in day care. Arch Pediatr Adolesc Med. 1995;149:1113-1117. Abstract.
8. Belshe RB, Gruber WC. Prevention of otitis media in children with live attenuated influenza vaccine given intranasally. Pediatr Infect Dis J. 2000;19(suppl 5): S66-S71.
9. Eskola J, Kilpi T, Palmu A, et al. Efficacy of a pneumococcal conjugate vaccine against acute otitis media. N Engl J Med. 2001;344:403-409.
10. Black S, Shinefield H, Fireman B, et al. Efficacy, safety and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Pediatr Infect Dis J. 2000;19:187-195.
11. Jacobs MR. Prevention of otitis media: role of pneumococcal conjugate vaccines in reducing incidence and antibiotic resistance. J Pediatr. 2002;141: 287-293.
 
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