Otitis Media With Effusion Workup

Traditionally, laboratory tests have rarely been used in the workup and diagnosis of otitis media with effusion (OME) unless another process is suspected. History taking and physical examination are sensitive and specific enough to facilitate accurate diagnosis and treatment of the disease. Obtaining cultures is not routine for this condition but is in Tympanocentesis.

In rare cases, the erythrocyte sedimentation rate (ESR) is obtained to rule out bony destruction, or the complete blood cell (CBC) count is assessed to rule out active infection.

In acute otitis media (AOM) histologic studies of the temporal bone reveal vascular dilatation and hyperplasia, inflammation and metaplasia of the mucosa, gland formation, edema, and infiltration with a mononuclear cell population. These same findings may be present, to a lesser degree, in otitis media with effusion.

Plain radiography of the mastoid was once used effectively to screen for otitis media with effusion (OME), but this imaging study is now rarely used for this purpose, given the sensitivity of history and physical examination in helping diagnose the disease.

CT scanning

Computed tomography (CT) scanning is extremely sensitive and not needed for diagnosis. However, CT scanning is important in attempting to rule out potential complications of otitis media (eg, mastoiditis, sigmoid sinus thrombosis, erosion of bone with intracranial extension) or unusual lesions (eg, cholesteatoma). This imaging modality is particularly important in unilateral otitis media with effusion when a nasopharyngeal or eustachian tube mass must be ruled out.

MRI

Magnetic resonance imaging (MRI) is particularly useful in the workup for soft-tissue masses that may be contributing to middle ear effusions (MEE) because of its superior ability to delineate borders within soft tissues and help determine the extent of potential intracranial extension (often helpful in nasopharyngeal masses). In addition, MRI and its closely associated variants of magnetic resonance venography (MRV) and magnetic resonance arteriography (MRA) demonstrate complications such as thrombosis of the intracranial sinuses very well. However, when intracranial extension is present, either from invasion from the nasopharynx or the temporal bone, CT scanning helps define the bony anatomy more specifically and should be used in conjunction with MRI.

Tympanometry is perhaps the most useful of all tests in association with otitis media with effusion (OME). This test reveals a type B result in 43% of cases of otitis media with effusion and a type C result in 47% of cases.

Previously, compared with myringotomy, a type B tympanogram was an imperfect measure of otitis media with effusion, with 81% sensitivity and 74% specificity. Studies later than 2001 have shown a higher rate of sensitivity and specificity, both around 90%. This is likely because of improvements in the technology used.

This test is particularly useful in small children whose external auditory canals may be too small or too collapsible to permit adequate visualization of the tympanic membrane. However, in those younger than 7 months, tympanometry is unreliable because of excessive compliance of the external auditory canal. The 2003 Agency for Healthcare Research and Quality (AHRQ) evidence report states that tympanometry results in children older than 4 years are reliable.

Tympanometry is a cost-effective adjunct to physical examination. Several studies have compared this test with pneumatic otoscopy in terms of accuracy in detecting middle ear effusion when compared with the criterion standard of myringotomy. Nearly all studies show that pneumatic otoscopy is slightly more sensitive, at around 93%, but they differ on specificity, showing rates from 50% to 88%. Many of the conclusions in these protocols stated that the greatest use for tympanometry is in aiding the clinician in ruling out middle ear effusion (MEE) for what appears to be an immobile tympanic membrane on examination.

According to the May 2004 clinical practice guideline on otitis media with effusion by the joint efforts of the American Academy of Family Physicians (AAFP), the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS), and the American Academy of Pediatrics (AAP) Subcommittee on Otitis Media With Effusion, audiology is a necessary component of the evaluation of certain patients with this condition.^[5]

The guidelines referred to randomized trials that sought to determine if any long-term detrimental effects of otitis media with effusion were observed in children who have no hearing loss or risk factors for speech and language delay.^[5] When these children were followed for several years, no long-term detrimental effects were identified. Such results have shifted the paradigm for treatment such that chronic otitis media with effusion but without hearing loss is no longer an absolute indication for the placement of tubes in children who are not at risk for language delays.^[5]

Studies examining hearing sensitivity in children with otitis media with effusion report that average pure tone hearing loss at 4 frequencies (500, 1000, 2000, and 4000 Hz) ranges from normal hearing to moderate hearing loss (0–55 dB). The 50th percentile is about 25 dB hearing level (HL), and approximately 20% of ears exceed 35 dB HL.

The committee not only stated that initial hearing testing can be done in a primary care setting for children aged 4 years or older, but it also stated that conventional audiometry with earphones is performed with a fail criterion of more than 20 dB HL at 1 or more frequencies (500, 1000, 2000, 4000 Hz) in either ear.^[5]

Language testing has also been advocated in the clinical practice guidelines for children with hearing loss (pure tone average greater than 20 dB HL on comprehensive audiometric evaluation). Testing for language delays is important, because communication is integral to all aspects of human functioning. Young children with speech and language delays during the preschool years are at risk for continued communication problems and later delays in reading and writing.

Tympanocentesis involves the aspiration of effusion from the middle ear. This procedure can be performed as an office procedure, even in small children, if necessary. Tympanocentesis can serve as both a therapeutic procedure and a diagnostic procedure.^[6] The therapy consists of the removal of a middle ear effusion (MEE) that can impair hearing or cause a sensation of aural fullness.

The criterion standard for documentation of a middle ear effusion is myringotomy, which has the advantage of increased exposure and better suctioning relative to tympanocentesis.^[7] The primary disadvantage is a larger incision with a greater, albeit small, chance of persistent perforation or otorrhea.