Outer and Middle Ear Disorders
The outer (external) and middle ear comprise the receptive and transformer structures for the auditory system. The external ear includes the auricle (also referred to as the pinna) and the external auditory canal. The external auditory canal is a skin-lined opening that ends at the eardrum or tympanic membrane. The subcutaneous support of the outer third of the external canal is cartilage, whereas the medial two-thirds of the canal (i.e., the portion adjacent to the tympanic membrane) is bony. The tympanic membrane has three cellular layers: the lateral squamous cell layer, the middle fibrous layer, and the medial respiratory epithelial layer. The tympanic membrane is held in position by a bony trough located at the medial end of the external auditory canal in which a fibrous ligament called the annulus resides. The superior portion of the membrane contains a higher proportion of elastin within its fibrous layer and is referred to as the pars flaccida; the rest of the membrane is referred to as the pars tensa.
The middle ear is an aerated space that begins laterally with the tympanic membrane and ends medially with the bony encasement of the cochlea and the vestibule. The middle ear space is divided into separate regions based on their relationships to the tympanic membrane annulus. The protympanum is the anterior-most space of the middle ear and contains the opening of the Eustachian tube, which connects the middle ear to the nasopharynx. The mesotympanum is on the same plane as the tympanic membrane and it contains the handle of the malleus, the long process of the incus, the stapes, the oval and round windows, and the tympanic segment of the facial nerve. The hypotympanum is inferior to the annulus and is the typical location of the bony covering of the jugular bulb; however, this bulb may lack a bony covering, creating a risk of jugular bulb injury during middle ear surgery. The epitympanum is above the tympanic membrane and is closely related to the pars flaccida portion of the tympanic membrane. This space contains the head of the malleus and the short process of the incus and is confluent with the air cells of the mastoid portion of the temporal bone by an opening called the additus ad antrum. The external and middle ears are surrounded by vital neural and vascular structures that can become involved in the disease processes that affect the ear. (For more information on the anatomy and physiology of the outer and middle ears, see Musiek and Baran, 2020, and Chapter 2, “Structure and Function of the Auditory and Vestibular Systems.”)
A wide variety of diseases, both congenital and acquired, can affect this portion of the auditory system, resulting in significant hearing dysfunction. As a whole, diseases of the external and middle ears are quite prevalent and account for a large portion of health care resources. This chapter examines a selection of the diseases and conditions that affect the external and/or middle ears.
Aural atresia is a condition in which the external auditory canal (EAC) fails to develop properly, resulting in an abnormally closed or absent canal (see also Chapter 9, “Hereditary and Congenital Hearing Loss”). Any interruption of the embryologic development of the EAC can result in atresia with varying degrees of severity. This condition is usually congenital in nature; however, acquired atresia can also occur and is most commonly related to chronic infections or trauma of the external auditory canal.
Atresia of the external auditory canal is typically discovered during a newborn screening examination. The condition is characterized by the absence of an external auditory canal or the presence of a blind pouch in the canal, and it may involve one or both ears. Microtia, which is the malformation or absence of the pinna, is frequently present with aural atresia; however, the pinna is normal in many patients with atresia. The middle ear may also be involved in individuals with aural atresia. In these cases, the tympanic membrane is typically absent and the ossicles may be significantly malformed or completely absent. In addition, the inner ear may be malformed; however, this condition is less common than external and/or middle ear malformations due to the separate and distinct embryologic development of the inner ear. When the EAC is shallow or blunted, the atresia may not be identified at birth and diagnosis is often delayed until entrance into school. In these cases, a routine hearing screening test administered in school may identify hearing loss and ultimately lead to the medical diagnosis of aural atresia.
The absence of an external canal results in a conductive hearing loss. In the event that the condition is bilateral and left untreated, the patient is likely to experience significant speech and language delays. The external canal, if not completely absent, may be as small as a pinpoint in size. This narrowing, or stenosis, of the ear canal may lead to the collection of epithelial skin cells in the external auditory canal—a condition known as an external canal cholesteatoma that can result in inflammation, pain, and/or aural discharge (otorrhea). Other systemic congenital anomalies may be present, but special attention should be paid to craniofacial anomalies, such as cleft palate, which may be an important consideration during perioperative airway management (see Schuknecht, 1989).
Congenital aural atresia generally occurs in 1 out of 10,000 to 20,000 live births. Typically, males are affected more than females and unilateral atresia is approximately three times more common than bilateral atresia (De la Cruz & Chandrasekhar, 1994). Also, the right ear tends to be involved slightly more frequently than the left ear, and the atretic portion of the external canal is more frequently bony rather than membranous (Jahrsdoerfer, 1978).
This condition is primarily a congenital malformation of the external ear canal that may occur in conjunction with a number of syndromes (e.g., Pierre Robin, CHARGE, VATER, Goldenhar, and Treacher Collins). Anomalies of the ear tend to develop along with other craniofacial malformations during the early stages of fetal development due to their common embryologic origins. Five branchial arches and their associated structures form the major structures of the head and neck. The ossicles begin to develop in the 4th gestational week and this process continues to the 16th gestational week when the ossicles reach adult size. During the 8th gestational week, the first branchial groove forms a plug of cells that migrates medially to oppose the developing middle ear cleft. The plug of cells begins to hollow out to form an epithelial-lined external auditory canal during the 6th month of gestation. Any interruption during this external and middle ear development typically results in ossicular malformation or atresia of the canal (see Lambert, 1998).
The severity and location of aural atresia can be classified in a number of ways. A commonly used classification system was described by Schuknecht (1989). Type A, or meatal atresia, involves the lateral cartilaginous portion of the canal, which is extremely narrowed in the atretic ear, preventing sloughing skin cells and cerumen from exiting the external canal. These sloughing skin cells can form a cyst, which then can erode soft tissue and bony structures. Type B, or partial atresia, involves a narrowing of the cartilaginous and bony portions of the canal. In this condition, the narrowed ear canal typically allows visualization of the tympanic membrane, but malformations of the ossicles are common. Type C, or total atresia, involves complete atresia of the cartilaginous and bony portions of the canal; however, the mastoid and middle ear are aerated. The bone adjacent to the middle ear is referred to as the atretic plate. The tympanic membrane is typically absent, and the ossicles are fused and frequently adherent to the atretic plate. Type D, or hypopneumatic atresia, is similar to type C; however, the mastoid is poorly pneumatized and the facial nerve has an aberrant course within the temporal bone.
The audiologic evaluation of an individual with atresia can be difficult, but it is a critical component of the diagnostic workup, especially in the case of pediatric patients. Audiologic evaluation is accomplished through two different approaches (routine threshold test procedures or threshold auditory brainstem response [ABR] tests) that are dependent on the presence of either unilateral or bilateral atretic involvement (see discussion that follows). Either way, when evaluating an infant or a very young child, the recommended approach is through the use of the auditory brainstem response (ABR) evaluation.
Most individuals with atresia present with a significant conductive hearing loss on the involved side. If a patient presents with involvement of only one ear, auditory sensitivity should be determined initially for the normal or nonatretic ear. This may be accomplished using standard audiometric test procedures, if feasible. However, in cases of infants, young children, or difficult to test patients, an ABR procedure may be used. It is recommended that a frequency-specific ABR (tone-bursts) be used in order to establish the level of hearing sensitivity across a range of frequencies. Once air-conduction hearing thresholds have been established, it is recommended that bone-conduction testing be performed on the atretic side with masking delivered to the uninvolved ear.
In cases of bilateral atresia, bone-conduction ABR is critical in determining serviceable hearing; however, it is nearly impossible to determine with any degree of certainty which ear is the better hearing ear due to the presence of the bilateral conductive loss and related masking dilemmas.
Atresia of the external auditory canal is typically found during a routine neonatal screening examination shortly after birth, as it may be heralded by microtia. The examination of aural atresia begins with inspection and palpation of the head and neck. The patient may have dysmorphic features or craniofacial anomalies that may require further workup and intervention prior to addressing the aural atresia (e.g., as in the case of Pierre Robin sequence syndrome with cleft palate). Otologic examination involves inspection and palpation of the auricle with careful photographic documentation of any degree of microtia. One must also examine facial nerve function as the facial nerve may have a highly variable course in atretic ears. Examination of the external auditory canal may be limited, but an attempt to evaluate the canal must be made. The use of a microscope to inspect the canal may uncover a stenotic or narrowed meatus and allow for cleaning of cerumen and squamous debris. Computed tomography (CT) scanning is vital in determining the location and severity of the compromise, as well as to aid in preoperative planning. The gold standard imaging procedure is a high-resolution CT scan of the temporal bone with 1- to 2-mm slices.
Audiologic management in cases of atresia varies depending on a variety of factors (i.e., unilateral versus bilateral atresia, hearing sensitivity of the nonatretic ear in cases of unilateral atresia, the extent of the atresia, the age of the patient, etc.). If serviceable hearing is documented through pure-tone testing, a bone-conduction hearing aid is often a viable option in many cases (Declau, Cremers, & Van de Heyning, 1999). Keeping in mind, however, that in cases of unilateral atresia, if the nonatretic ear demonstrates any degree of hearing loss, this should be managed with traditional amplification or medically if indicated. For preschool and school-age children, utilization of an FM system in the classroom should be considered in order to provide them with the best possible signal-to-noise ratio in an effort to maximize their speech understanding and academic success.
The type of treatment utilized for aural atresia is based on the severity of disease. Documentation of audiologic function must occur early in the evaluation of these patients, whether by bone-conduction audiometry or evoked auditory responses. Careful examination of the CT scan must be performed. Lack of sensorineural function and/or the presence of a malformed inner ear are contraindications for surgical intervention. Jahrsdoerfer and colleagues developed a 10-point grading scale of temporal bone anatomy that is used commonly today in determining candidacy for surgical intervention (Jahrsdoerfer, Yeakley, Aguilar, Cole, & Gray, 1992). The grading scale is based on a system that awards points for the normal radiographic appearance of specific temporal bone structures. Specifically, 2 points are awarded for the presence of a stapes and 1 point is awarded for the presence of a normal finding for each of the following structures: open oval window, middle ear space, facial nerve, malleus/incus complex, pneumatized mastoid, incus-stapes connection, round window, and the appearance of the external ear. A score of 10 would suggest an excellent candidate, whereas a score of 5 or less is considered poor and disqualifies a patient for surgical intervention.
Surgical correction of the atretic ear canal is difficult and requires a combination of skill and experience. Typically, microtia is surgically addressed by a reconstructive surgeon prior to the creation of a new external auditory canal. Microtia repair usually occurs when the child reaches 6 or 7 years of age and aural atresia repair is performed 1 to 2 years later. Patients with incomplete atresia or stenotic ear canals require careful cleaning of the canal and close follow-up to prevent cholesteatoma formation and/or canal restenosis. If the canal cannot be cleaned adequately, then surgical correction becomes necessary.
Repair of the atretic canal involves a postauricular incision and the drilling of a new external auditory canal within the temporal bone while carefully avoiding the mastoid air cells, the middle cranial fossa dura mater, and the facial nerve. Once the middle ear is reached, careful inspection of the ossicles is performed. A tympanic membrane graft is fashioned from temporalis fascia and draped over the ossicles. A skin graft is then carefully placed into position to provide the lining for the newly created canal. Patients are followed closely as outpatients, and debridement of the canal is performed frequently in the clinic using a microscope.
Patients who are poor reconstructive surgical candidates based on their scores on the Jahrsdoerfer grading scale may be candidates for amplification using a softband bone-anchored device or a surgically implanted osseointegrated device. The softband option involves attaching a bone-conduction device to a headband by means of special plastic snap. The bone-conduction device is then positioned on the head over the mastoid process and sound is transmitted to the cochlea through bone-conduction mechanisms. It is ideal for infants and young children who are not yet candidates for surgical intervention. Patients must have a significant sensorineural reserve to be candidates for the placement of this type of device, as well as for the implantation of an osseointegrated device. For patients who are candidates for an osseointegrated device, the surgical implantation process involves the placement of a metal implant in the temporal bone to which a hearing aid can be attached externally. Similar to a bone-conduction hearing aid, an osseointegrated device directly conducts sound through the temporal bone to the cochlea.
Case 4–1: Canal Atresia and Stenosis
History
This 1-month-old female was referred for an audiologic evaluation due to a failure on her newborn hearing screening bilaterally. She was accompanied to her appointment by her mother who reported no significant family history or risk factors for hearing loss. The patient’s birth history was unremarkable; however, her mother reported that her daughter had been evaluated previously by a pediatrician who had diagnosed one definitive episode of otitis media.
Audiology
Upon otoscopic examination, the tympanic membranes could not be visualized in either ear; however, this was not due to debris in the ear canal. Tympanograms were attempted and yielded atypical findings. Results demonstrated flat tracings with small equivalent ear canal volumes bilaterally. While this could initially be interpreted as an error in test administration (incorrect probe placement against the canal wall), this finding actually supports the “ultimate” clinical diagnosis of atresia and stenosis that was rendered following completion of the infant’s audiologic, medical, and radiologic assessments. Due to the patient’s age, an ABR test was performed (Figure 4–1A) during her audiologic evaluation. Results for a click-stimulus ABR yielded no identifiable waveforms for the right ear and a threshold at 80 dB nHL (70 dB estimated hearing level) for the left ear. An unmasked bone-conduction response was obtained at 45 dB nHL (estimated hearing level 25 dB HL). Frequency-specific ABR results could not be obtained at the time of this evaluation as the patient awoke prior to test completion. Due to the abnormal results noted during her audiological evaluation, the patient was referred to otolaryngology for further evaluation.
Medical Examination
The patient presented with normal appearing mastoids and pinnae; however, the tympanic membranes could not be visualized during a routine otoscopic exam. Given the abnormal clinical exam, it was recommended that the infant undergo an examination under the microscope in the operating room along with imaging studies. In addition, it was recommended that the ABR be repeated in the operating room for confirmation of results. Once in the operating room, the medical examination under the microscope confirmed what first appeared to be bilateral canal atresia. The ABR was repeated under sedation and results confirmed the presence of a significant hearing loss bilaterally. Due to the presence of significant ear canal compromise bilaterally, it was not possible to effectively mask each ear independently; however, given the click-evoked ABR test results suggesting a moderately severe hearing loss in the left ear, a profound hearing loss in the right ear, and a normal to near normal unmasked bone conduction threshold, coupled with the medical finding of canal atresia on the left side and severe stenosis on the right side, it is likely that there is a significant conductive hearing loss or component bilaterally. However, at this time a definitive determination of the exact type, extent, and configuration of hearing loss in each ear cannot be made.
Figure 4–1. Auditory brainstem response results (A) and imaging results (B) for an infant with canal atresia and stenosis (Case 4–1). The upper two waveforms in both figures are air-conduction results, while the lower two waveforms on the left-hand figure are unmasked bone-conduction results.
A CT scan was also ordered to further evaluate the auditory structures (Figure 4–1B). Results from the CT procedure demonstrated normal internal auditory canals and a normal middle ear space with all three ossicles appearing normal in structure and size in both ears. The cartilaginous external auditory canals were patent bilaterally; however, they appeared to terminate near the junction of the bony external auditory canals. In addition, both cochleae appeared normal. The CT images revealed a complete osseous obstruction of the left external auditory canal at the bony canal, and severe stenosis of the right external auditory canal was observed.
Impression
External auditory canal atresia of a significant portion of the left ear canal and severe canal stenosis of the right ear.
Audiologic Recommendations and Management
Given the fact that the patient presented with a maximum conductive hearing loss in at least one ear and most likely in both ears (see previous discussion) secondary to canal atresia (left ear) and stenosis (right ear), it was recommended that the patient be fit with a softband bone-anchored device. The patient’s mother had a consultation with the audiologist following medical clearance (see the following section) and the patient was fit with the recommended softband device. It was recommended that further frequency-specific results for bone conduction be obtained in order to maximize the device fitting and patient outcomes.
Medical Recommendations and Management
The patient was medically cleared to be fit with a softband device. While too young to prescribe an exact course of medical management for the outer ear conditions identified, the patient will be closely monitored with appropriate medical recommendations and interventions to follow in the future.
Eustachian tube anatomy and function is vital as it connects the middle ear space with the nasopharynx, and dysfunction of this connection can lead to significant otologic disease (Bluestone, 1998). The middle ear opening to the Eustachian tube is located in the anterior medial aspect of the middle ear. The proximal one-third of the tube passes through the petrous portion of the temporal bone. The distal two-thirds is primarily cartilaginous and terminates in the superior-lateral aspect of the nasopharynx. Redundant cartilage of this tube protrudes into the nasopharynx and is referred to as the torus tubarius. Two muscles, the tensor veli palatini and the levator veli palatini, which have attachments to the palate, are responsible for active dilation of the distal portion of the Eustachian tube. Bluestone describes the three physiologic functions of the Eustachian tube as (1) ventilation of the middle ear, (2) protection from the nasopharynx, and (3) clearance of secretions of the middle ear.
The Eustachian tube is a dynamic structure that is closed at rest but opens passively in response to changes in atmospheric pressure and actively in response to activities such as sneezing, swallowing, or yawning. The tube also can be opened forcibly by autoinsufflation. If the tube fails to open or becomes blocked, the air within the middle ear is absorbed, creating a vacuum or a negative pressure condition. This negative pressure leads to retraction of the tympanic membrane and may lead ultimately to further disease of the middle ear (e.g., otitis media). In some individuals, the tube may be abnormally patent (i.e., open), which is referred to as a patulous Eustachian tube.
The symptoms of Eustachian tube dysfunction depend on the type of dysfunction present. Occlusion of the tube that results in negative middle ear pressure typically results in a sensation of pain and pressure in the ear as the tympanic membrane retracts. Patients also indicate difficulty in “popping” their ears by autoinsufflation, and they may also experience tinnitus and disequilibrium. Chronic occlusion of the tube may lead to the development of serous fluid collection within the middle ear, a condition referred to as otitis media with effusion. This effusion leads to a conductive hearing loss, and the fluid may become infected, leading to acute otitis media. Persistent effusion with associated conductive hearing loss may affect speech and language development in children (Dhooge, 2003).
Patients with patulous Eustachian tubes experience autophony, which is the perception of one’s own breathing and speech as being excessively loud. This perception of increased loudness of one’s breathing and speech is due to the existence of a persistently patent or open tube.
According to Bluestone (2004), Eustachian tube dysfunction affects 70% to 90% of children by the age of 2 years. He also reported that Eustachian tube dysfunction is more common in children less than 5 years of age as well as in males, Native Americans, and patients with lower socioeconomic status. In addition, Eustachian tube dysfunction reportedly accounts for more than 2 million adult medical visits per year (McCoul et al., 2019).
Middle ear disease is extremely prevalent in children and can be attributed primarily to a developing Eustachian tube. The fundamental differences between pediatric and adult Eustachian tube anatomy accounts for the increase in dysfunction of this tube in children as compared to adults. The Eustachian tube is shorter in children and reaches adult size by 7 years of age (Sadler-Kimes, Siegel, & Todhunter, 1989). In addition, the tube slopes approximately 10º from the horizontal plane of the skull base in infants and young children compared with a 45° slope that is noted in adults (Proctor, 1967). These differences can have a detrimental effect on middle ear ventilation, protection, and fluid clearance.
Obstruction of the tube may be due to intrinsic inflammation within the nasal cavity, the middle ear, or the tube itself. Tobacco use, gastroesophageal reflux, nasal polyps, allergic rhinitis, chronic sinusitis, and upper respiratory infections are common causes of this inflammation. Functional obstruction can also occur in children with cleft palate defects because the peritubal muscles are unable to effectively open the distal portion of the Eustachian tube. Extrinsic obstruction of the Eustachian tube may also result from the presence of a mass within the nasopharynx, such as a nasopharyngeal carcinoma or adenoid hypertrophy.
Patulous Eustachian tube has been associated with extensive weight loss and pregnancy, which may deplete peritubal soft tissue mass or change tissue characteristics, respectively, allowing the tube to abnormally remain open. In addition, a neurologic insult, such as a stroke, and degenerative neurologic disorders, such as multiple sclerosis, may lead to muscle atrophy, allowing for abnormal tube patency.
The site of pathology leading to Eustachian tube dysfunction may lie on multiple levels. The primary pathology may reside within the nasal cavity as described previously with either inflammation or a mass effect obstruction. In addition, the tube can be obstructed due to inflammation within the tube itself, or it functionally may not open due to peritubal muscle dysfunction. Typically, the site of lesion does not lie within the bony portion of the Eustachian tube.
Traditional audiologic evaluation typically includes tympanometry to assess middle ear function (see Chapter 3, “Audiologic, Vestibular, and Radiologic Procedures”). Tympanometry was first reported in the assessment of Eustachian tube dysfunction in the late 1960s (Holmquist, 1969) and has been an integral part of the evaluation since that time (Leo, Piacentini, Incorvaia, & Consonni, 2007). A number of tests can be performed with tympanometric procedures to measure Eustachian tube function. These generally require acquiring a baseline tympanogram, then creating positive and/or negative pressure in the ear canal and asking the patient to swallow several times. Following this procedure, the tympanogram is retraced and if the peak pressure changes, the Eustachian tube is functioning. If there is no change in the peak pressure, the findings suggest Eustachian tube dysfunction.
During tympanometric testing, individuals with patulous Eustachian tubes often show oscillations that correspond to the patient’s breathing patterns (inhalations and exhalations), with these oscillations becoming more notable with hard breathing (see Fowler & Shanks, 2002, for additional discussion).
When using regular tympanometry, patients who present with Eustachian tube dysfunction (exclusive of patulous tubes) often present with either negative pressure and/or reduced compliance. In addition, a traditional audiologic evaluation including pure-tone threshold testing, speech recognition thresholds, and speech recognition testing is recommended to determine if the Eustachian tube dysfunction has impaired the patient’s hearing sensitivity and/or speech understanding. If hearing loss is present, it will be either conductive or mixed in nature (dependent on whether or not a preexisting sensorineural loss is present).
A thorough examination of the head and neck is vital to diagnosing the etiology of Eustachian tube dysfunction. Otoscopy with pneumatic insufflation is key to determining the appearance of the tympanic membrane, the presence of an effusion, and the compliance of the tympanic membrane. Rhinoscopy assists in identifying nasal masses or inflammatory conditions. A thorough evaluation of the nasopharynx is mandatory and can be accomplished by direct inspection with a rigid or a flexible nasopharyngoscope. A Valsalva test involves forced expiration with a closed mouth and an occluded nose while the tympanic membrane is inspected. A tympanic membrane bulging laterally as the middle ear space is filled with air indicates a patent Eustachian tube. A Politzer test involves inspection of the tympanic membrane while air is injected into the nasopharynx as the patient swallows. The tympanic membrane should respond in a manner similar to the Valsalva test.
Radiographic evaluation with plain film, lateral view X-ray of nasopharyngeal soft tissue may reveal adenoid hypertrophy or other nasopharyngeal masses. Computed tomography (CT) and magnetic resonance imaging (MRI) can clearly delineate skull base anatomy and pathology and is routinely utilized in evaluation of masses of the nasopharynx.
In most instances, Eustachian tube dysfunction is managed otologically. Audiologic support for this is primarily diagnostic in nature.
Management of Eustachian tube dysfunction depends on the etiology. Inflammatory conditions such as allergies or upper respiratory infections are typically treated medically with oral steroids, intranasal steroid sprays, antihistamines, and/or allergy immunotherapy. Obstruction, whether intrinsic or extrinsic, that has been refractory to medical management typically is treated with myringotomy and placement of a pressure equalization (PE) tube (also referred to as a tympanostomy tube) in the tympanic membrane in order to equalize the pressure between the middle ear and the external environment, thus bypassing the role of the Eustachian tube in this function (Bluestone, 2004). It should be noted that although Eustachian tube dysfunction is most common in children, it is not uncommon for it to be observed in adults.
Case 4–2: Eustachian Tube Dysfunction
History
This 52-year-old male reported 6 weeks of chronic aural fullness and pressure with no noticeable hearing loss. He also reported occasional tinnitus, which he described as a “cracking” sound. No other significant audiologic or otologic symptoms were reported.
Audiology
Routine pure-tone testing revealed hearing thresholds within normal limits for both ears and excellent word recognition performance was noted bilaterally (Figure 4–2). Tympanometry indicated normal volume and compliance bilaterally with excessive negative pressure bilaterally.
Medical Examination
The patient presented with normal appearing mastoids, pinnae, ear canals, and tympanic membranes without evidence of fluid, perforation, or retraction.
Figure 4–2. Pure-tone, speech audiometry, and tympanometry results for a 52-year-old male with Eustachian tube dysfunction (Case 4–2).
Bilateral Eustachian tube dysfunction.
Audiologic Recommendations and Management
It was recommended that the patient follow up with an otolaryngologist, with subsequent audiologic follow-up as necessary.
Medical Recommendations and Management
Following medical and audiologic evaluation, it was recommended that the patient undergo a bilateral myringotomy and PE tube placement under local anesthesia in the office.
Additional Comments
The patient received significant benefit from the bilateral PE tube placement, with relief of his pressure and aural fullness symptoms noted posttube placement bilaterally.
Otitis media refers to inflammation of the middle ear and involves a broad range of disease processes. This inflammation, which is typically preceded by some form of Eustachian tube dysfunction, is accompanied by a fluid collection (or effusion) behind the tympanic membrane. In acute otitis media, a purulent effusion develops rapidly due to bacterial colonization and is characterized by systemic symptoms. This purulent effusion may resolve into a serous effusion (a collection of fluid in the middle ear space) before complete resolution occurs. The presence of a serous effusion for more than 30 days, regardless of etiology, is referred to as chronic otitis media with effusion. The condition where either three or more bouts of acute otitis media occur within 6 months, or four or more episodes of acute otitis media occur in 1 year, is referred to as recurrent acute otitis media. Chronic suppurative otitis media refers to persistent inflammation and disease of the middle ear with compromise of the tympanic membrane. Due to the fact that it is often associated with cholesteatoma, further discussion of this chronic condition is reserved for the cholesteatoma section of this chapter.
Otitis media is ubiquitous and may be due to a variety of etiologies. Infections, allergies, and environmental factors have all been found to contribute to otitis media (Danishyar & Ashurst, 2019). Common etiologies include, but are not limited to, immunodeficiencies, anatomic abnormalities, viral pathogens, passive smoke exposure, and daycare attendance (Bluestone, 2004). It has also been well established that exposure to secondhand smoke significantly increases the risk for otitis media in children (Jones, Hassanien, Cook, Britton, & Leonardi-Bee, 2012). Otitis media accounts for one of the most common pediatric diagnoses made by primary care providers and results in a significant consumption of health care funds annually (Bluestone, 2004).
Acute otitis media typically is accompanied by fever, otalgia, pressure, and irritability. These symptoms may be decreased or absent in older patients. Although acute otitis media usually is responsive to antimicrobial therapy, complications that can occur include meningitis, labyrinthitis, petrositis, brain abscess, facial paralysis, and coalescent mastoiditis. Any evidence of mental status change in the case of acute otitis media or of a failure of symptoms to improve following appropriate medical treatment should raise the suspicion of one of these complications.
The presence of an effusion also causes a conductive hearing loss. In some cases, chronic otitis media with effusion may be completely asymptomatic with the exception of a conductive hearing loss. As small children are prone to this condition, they may be unable to adequately describe their symptoms, particularly the presence of a hearing loss. It therefore falls on clinicians to look carefully at these patients for any “hidden” symptoms.
Otitis media can occur across the life span, but is more common in children than adults. Acute otitis media is extremely prevalent. A recent study evaluating the epidemiology of acute otitis media found that by 1 year of age, 23% of children experience more than one episode, with this rate increasing to 60% by 3 years of age (Kaur, Morris, & Pichichero, 2017). This middle ear condition is more common in young children and occurs much less frequently in children over the age of 6 years (O’Neill, Roberts, & Bradley Stevenson, 2006). The rates of acute otitis media are higher in children with repeated exposure to large numbers of other children, such as in day care settings (Paradise et al., 1997). Approximately 2.2 million episodes of otitis media with effusion are diagnosed annually in the United States (Rosenfeld et al., 2016).
Otitis media with effusion typically presents in children less than 6 years of age and may be secondary to upper respiratory infections or acute otitis media (Rovers, Schilder, Zielhuis, & Rosenfeld, 2004). The rate of middle ear effusion is reported to be higher in pediatric patients in an ICU setting than in other settings (Derkay, Bluestone, Thompson, & Kardatske, 1989), and the overall incidence of chronic otitis media with effusion in children is reported to range from 15% to 20% (Zielhuis, Rach, van den Bosch, & van den Broek, 1990).
An upper respiratory viral infection commonly occurs in conjunction with acute otitis media and results in a breakdown of the protection that the nasal mucosa provides against bacterial infection (Henderson et al., 1982). The primary cause of otitis media is Eustachian tube dysfunction. When bacteria are allowed to colonize the middle ear space, otitis media occurs. The most common bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis (Bluestone, Stephenson, & Martin, 1992). Conditions that impair immune system function, such as diabetes or HIV, can increase the risk of infection. Anatomic abnormalities of the Eustachian tube secondary to craniofacial conditions such as cleft palate also increase risk of acute otitis media. Tobacco smoke exposure, adenoid hypertrophy, lower socioeconomic status, and group day care attendance are additional risk factors. Finally, chronic infectious or inflammatory granulomatous diseases, such as tuberculosis or Wegener’s granulomatosis, can induce exudation of fluid from the middle ear mucosa and lead to the development of otitis media (da Costa & Polanski, 2015).
Otitis media, by definition, is located primarily in the middle ear; however, as previously described, its etiology depends on Eustachian tube dysfunction as bacteria typically migrate or reflux into the middle ear from the nasopharynx. Due to the confluent relationship between the middle ear and the mastoid, an effusion that fills the middle ear typically extends into the mastoid as well. Therefore, patients with serous otitis media or acute otitis media will often be found to have fluid in their mastoid air cells as well as their middle ears on CT scans. In the situation of acute otitis media, increasing middle ear pressure due to accumulating purulent effusion can lead to perforation of the tympanic membrane and drainage of pus into the external auditory canal (Bluestone & Klein, 2003).
In cases of otitis media, the audiologic evaluation is an integral part of the entire medical workup. The audiologic examination for the patient with otitis media typically includes tympanometry and routine audiologic evaluation appropriate to the patient’s age (Aithal, Aithal, & Pulotu, 1995). Tympanometry, although first introduced by Metz in the mid-1940s (Metz, 1946), truly began its clinical integration in the early 1970s. Tympanometry allows for objective evaluation of the middle ear status with most patients with otitis media presenting with negative pressure and/or reduced compliance. As the disease progresses, tympanograms typically change from a negative pressure peak early on to a flat tympanometric configuration (little to no compliance) with significant fluid accumulation in the middle ear at advanced stages of the disease. The audiologic evaluation typically reveals a conductive or mixed hearing loss (depending if a preexisting sensorineural loss is present). Although in the early stages of development of otitis media (i.e., when Type C tympanograms are observed), hearing thresholds may fall within normal limits. The configuration of the hearing loss, if one is noted, is usually rising (i.e., poorer hearing thresholds in the low frequencies when compared to the high frequencies). This ascending contour is often noted at the beginning of the disease process as the tympanic membrane and the ossicular chain increase in stiffness with decreasing middle ear pressure. As the fluid in the middle ear accumulates over time, a mass effect may result, and the configuration flattens as the high frequencies also are compromised. The degree of hearing loss is usually in the mild range (20 to 40 dB HL), but it can fluctuate considerably (Jerger & Jerger, 1981).
Pneumatic otoscopy is key to the diagnosis of otitis media. In acute otitis media, the tympanic membrane appears red and bulging; however, the purulent middle ear effusion behind the eardrum may not be easily visualized due to thickening of the tympanic membrane. Chronic otitis media with effusion is characterized by a clear, honey-colored fluid in the middle ear. A thorough examination of the upper aerodigestive tract is indicated to identify associated diseases and/or the etiologic causes for otitis media. In addition, the palate must be examined if an adenoidectomy is being considered. Performing an adenoidectomy on a patient with a cleft palate or a submucous cleft can lead to velopharyngeal insufficiency and nasal reflux.
Due to the low incidence of otitis media in the adult population, the presence of unilateral effusion, without a clear precipitating event, is a concerning finding. A thorough evaluation of the nasopharynx in these cases must be performed to rule out a neoplasm. Appendixes 4A through 4D provide examples of a normal tympanic membrane, as well as eardrums with a variety of otologic conditions.
Audiologic management is reserved for cases in which hearing loss is present and traditional medical management is unsuccessful. Hearing loss typically ranges from mild to moderate depending on the stage of the disease. In such cases, either traditional hearing aids, softband bone-anchored aids, or osseointegrated devices are highly successful. However, long-term complications can develop if the underlying medical condition is not resolved, and patients should be made aware of this possibility (Hobson et al., 2010). Most patients with purely conductive hearing losses present with excellent word recognition abilities (90% to 100%); therefore, amplification will provide the additional gain needed for everyday functioning for patients for whom medical intervention is unsuccessful or contraindicated. These patients typically do well with and receive benefit from their hearing aids or devices. It should be kept in mind that long-standing, untreated conductive hearing loss is a form of auditory deprivation, which in some cases can affect higher-order auditory processes. If central auditory dysfunction secondary to auditory deprivation is suspected, then a central auditory processing assessment should be completed and appropriate management procedures implemented (see Chapter 7, “Disorders of the Central Auditory Nervous System”).
Acute otitis media can resolve spontaneously; however, the use of oral antibiotics helps to shorten the duration of symptoms and prevent complications. Compared with simple observation, treatment of acute otitis media with antibiotics results in a 25% decrease in pain in children less than 2 years of age (Rovers et al., 2006). Treatment of acute otitis media with antibiotics—such as amoxicillin, cephalosporins, and macrolides—are directed at the most common organisms found in the middle ear. However, there is some concern regarding the frequent usage of antimicrobial drugs and the bacterial resistance that can result (Goossens, Ferech, Vander Stichele, & Elseviers, 2005).
Recurrent acute otitis media is often surgically treated with myringotomy and PE tube placement. The 2016 American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) Clinical Practice Guidelines on otitis media with effusion have provided specific guidelines with respect to the recommendations of PE tube placement for children with chronic bilateral otitis media. The guidelines recommend that children with otitis media should be monitored in 3 to 6 months intervals until effusion has resolved, structural abnormalities are identified or suspected, or a hearing loss is diagnosed. With respect to PE tube insertion, the guidelines recommend that children ≥3 months of age with chronic otitis media and documented hearing difficulties be offered the option of PE tubes. The reader is referred to the AAO-HNS guidelines mentioned previously for a full review of the recommended guidelines.
The placement of the PE tube allows for adequate aeration of the middle ear space, preventing the accumulation of an effusion. Tympanostomy tubes also alleviate many of the symptoms of acute otitis media when it occurs. A great variety of tubes are available commercially that differ in size, duration of effectiveness, and composition. Tubes that remain in place longer have a higher risk of leaving a tympanic membrane perforation. Adenoidectomy can also be a key component of the treatment of otitis media. This procedure has been shown to decrease the morbidity of otitis media in some patients (Gates, Avery, Prihoda, & Cooper, 1987). This surgical procedure is typically performed in cases of persistent or recurrent otitis media following an initial trial with tympanostomy tubes. However, in general, adenoidectomy is not performed in children under the age of 2 years.
History
This 3-year-old female was seen for an audiologic evaluation following a failed preschool hearing screening test. The patient’s parents reported that their daughter had a history of occasional otitis media and a speech and language delay with no other significant audiologic, developmental, or neurologic symptoms reported.
Audiology
Pure-tone testing was completed using conditioned play audiometric procedures. Test results documented a mild conductive hearing loss in both ears (Figure 4–3A). Tympanometry revealed little or no compliance with normal ear canal volume measures bilaterally and word recognition was excellent for both ears.
Medical Examination
The patient presented with normal appearing mastoids, pinnae, and ear canals; however, evaluation of the tympanic membranes with a microscope revealed excessive purulent fluid in both middle ears.
Impression
Recurrent otitis media with effusion in both ears.
Audiologic Recommendations and Management
Reevaluation following medical intervention.
Medical Recommendations and Management
It was recommended that the patient undergo bilateral PE tube placement.
Additional Comments
A postoperative audiogram revealed normal peripheral hearing bilaterally (Figure 4–3B). Ear canal volume measures were larger in both ears than expected for a child of this age, indicating that the PE tubes were in place and were patent.
Figure 4–3. Pure-tone air- and bone-conduction thresholds, speech audiometry, and tympanometry results for a 3-year-old with bilateral otitis media (Case 4–3). Results are shown for both preoperative testing (A) and postoperative testing (B).
History
An 83-year-old male with a history of age-related hearing loss was evaluated due to a decrease in his hearing sensitivity and the report of a right-sided aural fullness following an upper respiratory infection lasting 6 months.
Audiology
Test results indicated a mild sloping to severe sensorineural hearing loss in the left ear and a moderate to moderately-severe mixed hearing loss in the right ear (Figure 4–4A). Tympanometry revealed normal pressure, volume, and compliance for the left ear and reduced compliance and negative pressure with normal volume for the right ear. Word recognition was fair bilaterally.
Medical Examination
The patient presented with a normally appearing mastoid, pinna, and ear canal bilaterally. Otoscopic examination of the tympanic membrane under the microscope revealed dullness with excessive fluid for the right side, and a normal tympanic membrane on the left side.
Impression
Otitis media with effusion in the right ear.
Audiologic Recommendations and Management
Reevaluation following medical intervention.
Medical Recommendations and Management
It was recommended that the patient undergo unilateral PE tube placement in the right ear under local anesthesia in the office.
Additional Comments
One month following PE tube placement, the patient’s postoperative audiogram revealed a symmetric sensorineural hearing loss with recovery of the conductive component in the right ear. Tympanometric testing for the right ear showed a large volume consistent with a patent PE tube (Figure 4–4B).
Chronic otitis media is a distinct entity from other forms of otitis media. This disease may manifest itself in the following conditions: persistent perforation of the tympanic membrane, erosion of the ossicles, the presence of granulation tissue in the middle ear, and cholesteatoma. The term, cholesteatoma, is used to describe a collection of keratin-producing squamous epithelial cells within the middle ear or mastoid. The term, however, is a misnomer in that a cholesteatoma is not a neoplasm. Johannes Müller first described this condition in the 19th century as “a pearly tumor” (Müller, 1838) and presumably this label led to the coining of the term, cholesteatoma, which continues to be the term used for this middle ear pathology. A cholesteatoma contains viable and nonviable squamous epithelial cells with a blend of osteolytic enzymes, cholesterol crystals, and keratin debris.
Figure 4–4. Pure-tone air- and bone-conduction thresholds, speech audiometry, and tympanometry results for an 83-year-old male with otitis media in the right ear (Case 4–4). Results are shown for both preoperative testing (A) and postoperative testing (B). continues
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