Otitis media and middle ear effusion

By Marcello Cherchi, MD PhD

For patients

The middle ear (the space immediately behind the eardrum) can become inflamed, or filled with fluid, or infected. Symptoms can include ear discomfort, hearing loss or disequilibrium. Your doctor may examine you by looking in your ear with a microscope or otoscope. In some cases, tests of hearing or balance function may be appropriate. If the cause is thought to be infectious, your doctor may prescribe a course of antibiotics. If that fails, then you may be referred to an otolaryngologist.

For clinicians

Overview

The middle ear space can be filled with a (non-inflammatory, non-infectious) effusion; it can be affected by inflammation (with or without effusion) or infection.  Typical symptoms include aural fullness and pain, and possibly hearing loss and disequilibrium.  This condition is more frequent in children, probably because of the orientation of the Eustachian tube.  Physical examination under otomicroscopy or otoscopy may show a fluid meniscus behind the tympanic membrane; in some cases there may be nystagmus, though the patterns of nystagmus are neither specific nor sensitive for these middle ear conditions.  The hearing loss, if assessed by audiometry, is usually conductive in nature.  Some cases may have detectable abnormalities on otovestibular testing (vestibular evoked myogenic potentials, video head impulse testing, ocular motor testing, caloric testing, rotatory chair testing, posturography).  Imaging is usually not necessary with an initial episode.  If there is reason to suspect infection, then empiric treatment with antibiotics is reasonable.  If that fails, then referral to otolaryngology is appropriate to be evaluated for myringotomy or placement of a grommet.

Terminology

The phrase “middle ear effusion” refers to fluid in the middle ear. If the fluid is neither inflammatory nor infectious, then it is usually referred to as a “serous middle ear effusion.”

The phrase “otitis media” refers to an inflammatory process in the middle ear space, irrespective of whether any effusion is also present. If fluid is also present but no infection is involved, then it is referred to as “serous otitis media.” If otitis media involves infection, then it is designated according to the pathogen (e.g., “bacterial otitis media,” “tuberculous otitis media,” etc.”).

Epidemiology

Middle ear effusion and inflammation are more common in children than in adults, though some studies have also been conducted on adults (Mostafa, Shafik et al. 2013, Kalaycik Ertugay, Kulekci et al. 2015, Aarhus, Tambs et al. 2016, Kim, Lee et al. 2021, Tailor, Phillips et al. 2022).

Risk factors for middle ear effusion and inflammation include Eustachian tube dysfunction.

Pathophysiology

Effusion, inflammation or infection in the middle ear space have the potential to provoke aural symptoms (pain, fullness), auditory symptoms (hearing loss, tinnitus) and vestibular symptoms (disequilibrium).

Presentation: Hearing loss

Hearing loss is fairly common in cases of otitis media (Leskinen 2005, Hyden, Akerlind et al. 2006, Kalaycik Ertugay, Kulekci et al. 2015, Kim, Yang et al. 2016, Kim, Lee et al. 2021). The associated hearing loss is usually conductive, and is due to mechanical interference with the motion of the ossicular chain.

The Figure below, from Zaidi and Sinha (Zaidi and Sinha 2013), shows bilateral conductive hearing loss in a case of chronic bilateral suppurative otitis media.

Presentation: Disequilibrium

Vestibular symptoms are less common than auditory ones in middle ear effusions and otitis media, but do occur (Grace and Pfleiderer 1990, Leskinen 2005, Hyden, Akerlind et al. 2006, Gianoli and Soileau 2008, Kalaycik Ertugay, Kulekci et al. 2015, Saliba, Dagher et al. 2015, Aarhus, Tambs et al. 2016, Kim, Yang et al. 2016, Monsanto, Kasemodel et al. 2018, Monsanto, Kasemodel et al. 2020, Kim, Lee et al. 2021, Tailor, Phillips et al. 2022).

It is certainly possible for otitis media to develop into labyrinthitis (Hyden, Akerlind et al. 2006, Kitsko and Dohar 2007, Zaidi and Sinha 2013, Kim, Yang et al. 2016, Choi, Han et al. 2019). In such cases, presumably pathogens pass from the middle ear to the inner ear by traversing the oval and/or round windows. Labyrinthitis has been well-studied, and it is unsurprising that such patients can have vestibular symptoms.

But there are other cases of middle ear effusions and otitis media that do not appear to evolve into labyrinthitis, yet are still associated with vestibular symptoms. In such cases, the mechanism by which the middle ear process provokes vestibular symptoms is unclear. Temporal bone studies of patients who in life had chronic otitis media show reduced density of type I and type II vestibular hair cells and of dark cells (da Costa Monsanto, Erdil et al. 2016), suggesting that even if these patients do not clinically present with a discrete episode suggestive of labyrinthitis, the chronic otitis media still provokes pathology in the labyrinth.

Physical examination: Otomicroscopy/otoscopy

A binocular otomicroscopic examination, or at least a monocular otoscopic examination, is important in these patients. A middle ear effusion is often (though not always) visible as a fluid meniscus behind the tympanic membrane.

The Figure below, from Bhutta and colleagues (Bhutta, Thornton et al. 2017), shows a fluid meniscus from a serous middle ear effusion.

Physical examination: Nystagmus

Some investigators report nystagmus of various patterns in cases of acute otitis media (Kim, Yang et al. 2016, Choi, Han et al. 2019, Kim, Lee et al. 2021), including direction changing positional nystagmus, and direction-fixed nystagmus (paretic or irritative). One series of patients with acute otitis media without vestibular complaints reported nystagmus in 82% (28 out of 34) of patients; we find this statistic impressive, and far greater than in our own experience.

Testing

Audiometry often shows hearing loss (usually conductive) in the affected ear (Eliashar, Gross et al. 2004, Zaidi and Sinha 2013, Tailor, Phillips et al. 2022). Tympanometry often shows reduced compliance (peak immittance).

Vestibular evoked myogenic potentials are sometimes abnormal (Mostafa, Shafik et al. 2013) in a middle ear with effusion or inflammation, but whether this is an artifact of conductive hearing loss or reflects true vestibular dysfunction is not always clear. In this regard, some studies are careful to compare air-conducted and bone-conducted vestibular evoked myogenic potentials (Kolkaila, Emara et al. 2015).

Some patients with middle ear effusion or inflammation exhibit abnormalities on video head impulse testing, usually in the form of the presence of corrective saccades, or reduced gain (Abdelmotaleb, Sobhy et al. 2023). Comert and colleagues (Comert, Sencan et al. 2021) more specifically observed covert compensatory saccades in 32% of the patients, and reduced gain in the anterior canal on the affected side.

Several studies have explored ocular motor function with electronystagmography or videonystagmography in patients with middle ear effusion and/or inflammation. Eliashar and colleagues reported an “abnormal electronystagmogram” in all patients who had vestibular complaints; these “abnormalities” included spontaneous nystagmus and direction changing nystagmus. Gianoli and colleagues reported unilateral or bilateral caloric weakness in 19 (76%) out of 25 patients with chronic suppurative otitis media (Gianoli and Soileau 2008). Golz and colleagues (Golz, Netzer et al. 1998) studied 136 patients with middle ear effusion and reported abnormal electronystagmographic findings in 58% of patients, including 42 (31%) who exhibited spontaneous unidirectional nystagmus, and 24 (17.5%) who exhibited positional nystagmus. Lee and colleagues (Lee, Park et al. 2009) studied 25 patients with unilateral chronic otitis media and reported that 20 (80%) showed some ocular motor abnormality, with 5 (20%) exhibiting unilateral caloric weakness, 12 (48%) exhibiting head shaking nystagmus, and 7 (28%) exhibiting vibration induced nystagmus. Mostafa and colleagues (Mostafa, Shafik et al. 2013) studied 58 adults (mean age 29.5 years) and found 62% had a caloric weakness. Saliba and colleagues (Saliba, Dagher et al. 2015) studied 15 children with chronic middle ear effusion and found 2 (13%) had abnormal ocular motor findings, 1 with positional nystagmus, and 1 with both spontaneous and positional nystagmus.

Mostafa and colleagues (Mostafa, Shafik et al. 2013) studied 58 adults (mean age 29.5 years) and found 70% of patients rotatory chair abnormalities.

Of other vestibular tests, Lee and colleagues (Lee, Park et al. 2009) studied 25 patients with unilateral chronic otitis media and reported that 5 (20%) had abnormal subjective visual vertical (suggesting otolith dysfunction).

Some studies report abnormal findings on static or dynamic posturography (Gawron, Pospiech et al. 2004, Monsanto, Kasemodel et al. 2020, Abdelmotaleb, Sobhy et al. 2023).

Interestingly, of patients with abnormal vestibular test findings, not all complain of disequilibrium. For example, Lee and colleagues (Lee, Park et al. 2009) studied 25 patients with unilateral chronic otitis media and reported that 20 (80%) showed some ocular motor abnormality, yet none of these patients complained of dizziness or vertigo. Kim and colleagues (Kim, Lee et al. 2021) used “video Frenzel glasses” to study 34 adult patients with acute otitis media and reported that 28 (82%) exhibited either direction changing positional nystagmus, direction-fixed irritative nystagmus or direction-fixed paretic nystagmus, yet none of these patients complained of dizziness or vertigo. These findings suggest that middle ear effusion and inflammation can cause sub-clinical vestibular deficits.

Imaging

Imaging is usually not warranted with an initial presentation of middle ear effusion/inflammation/infection. In a patient with recurrent bouts, imaging may be appropriate, though at that point the patient should probably have already been referred to otolaryngology. Otolaryngologists in that circumstance may consider an MRI of the skull base without and with contrast to evaluate for obstructive causes of Eustachian tube dysfunction, mastoiditis or an abscess.

Treatment: Medical

Many cases of middle ear effusion resolve spontaneously.

If a middle ear effusion develops a superimposed infection, then antibiotic therapy is appropriate. In a patient without penicillin allergy, a course of amoxicillin, or amoxicillin-clavulanate is reasonable. In a patient with a penicillin allergy, consider a course of cefdinir, cefuroxime or cefpodoxime. If those approaches fail, then (whether or not the patient has a penicillin allergy), consider a course of ceftriaxone. If antibiotic treatment is failing, then the clinician should have a low threshold for referral to otolaryngology.

Treatment: Surgical

For patients with infectious otitis media who have failed empiric courses of antibiotics, referral to otolaryngology is appropriate. Commonly attempted procedures in this circumstance include myringotomy (Kim, Yang et al. 2016) or placement of a grommet (Grace and Pfleiderer 1990, Golz, Westerman et al. 1991, Golz, Netzer et al. 1998). These case series report significant improvement in auditory and vestibular symptoms.

References