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How to treat Pull-out section

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inside Assessment Common causes of hearing loss in adults Treatment options Case studies

The authors

DR PATRICIA MACFARLANE, otolaryngology resident, Flinders Medical Centre, Adelaide, SA.

DR A SIMON CARNEY, senior lecturer and head of ENT unit, Flinders Medical Centre, Adelaide, SA.

HEARING LOSS

in ADULTS

Background

HEARING impairment is a common and often under-diagnosed condition affecting almost one in five people aged over 15 in Australia. This figure increases to almost 40% in people aged over 55, with men more likely to be affected than women, particularly in the older age groups. While it is often thought of as inevitable and part of the ageing process, hearing loss can cause significant disability with regard to a persons’ employment prospects, social interactions and, consequently, overall psychological wellbeing. GPs are often the first port of call for patients (or frustrated family mem-

bers) who are experiencing hearing difficulties. In most instances hearing loss will have a simple aetiology. However, there are a few important conditions in which hearing loss is a sign of more serious and possibly malignant disease. For some patients their hearing loss may be untreatable, but others may benefit from early diagnosis and referral to an otolaryngologist. This article aims to assist GPs in improving their otological examination skills and interpretation of tympanometry tests and audiograms, as well as reviewing some of the more recent advances in treating hearing loss in adults.

Types of hearing loss Historically hearing loss has been divided into three categories — conductive, sensorineural and mixed. Conductive hearing loss refers to conditions affecting the pinna, external auditory canal, tympanic membrane or middle-ear structures, which can impede the transmission of sound impulses from the external environment through to the stapes footplate. Such causes may be obvious on physical examination and are often amenable to treatment or surgical correction, although hearing aids may be a satisfactory non-surgical option for some patients. www.australiandoctor.com.au

Sensorineural hearing loss results from conditions affecting the inner ear or the central auditory pathway of the eighth cranial nerve and may be further subdivided into sensory (cochlear) and neural (auditory nerve and pathway) causes. Sensorineural hearing loss may occasionally be due to associated pre-existing medical conditions and may improve with control of the underlying disease process, but in most instances is not amenable to surgery. In such cases hearing devices may be of benefit. Mixed hearing loss is due to a combination of conductive and sensorineural processes. 31 August 2007 | Australian Doctor |

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How to treat – hearing loss in adults Assessment WHEN assessing a patient with hearing loss it is important to determine if they have experienced an acute loss of hearing (which is quite distressing and often prompts patients to present immediately to their GP or local emergency department), or if it has been a longstanding problem. Other symptoms to inquire about include the presence of tinnitus, vertigo, otalgia and otorrhoea, which together with findings on physical examination may identify the underlying cause of the hearing loss. In addition to taking a detailed medical history it is important to inquire about the following risk factors associated with hearing loss: ■ Environmental exposure to noise both at work and through hobbies such as hunting. ■ Family history of hearing impairment. ■ Previous head trauma. ■ Exposure to medications or chemicals known to be ototoxic (table 1). ■ Other medical problems such as diabetes, hypertension or Paget’s disease. As part of the initial physical examination in patients presenting with hearing loss, a brief cranial nerve examination as well as a basic assessment of vestibular function (simple recording of posture, balance and gait) should be undertaken. Wax obstructing vision in the external auditory canal needs to be removed before any assessment of hearing or otoscopic examination (figure 1). Agents that soften and help remove wax are available over the counter from pharmacies, although olive oil has been shown to be equally effective. Typically drops are applied to the affected ear twice a day for up to five days. Syringing of ears to remove wax is often performed in the community setting, but must not be undertaken in patients with known or suspected tympanic membrane perforations, a previous history of mastoid surgery or in the presence of acute infection or inflammation of the ear. During otoscopy the cause of a patient’s hearing loss may become apparent. Large or multiple bony exostoses of the external auditory canal, a condition also referred to as ‘surfer’s ear’ (figure 2), can cause a conductive deficit by significantly narrowing the diameter of the canal. The state of the tympanic membrane can give further clues as to the underlying aetiology. Tympanic membrane perforations or retractions, cholesteatoma (which may appear as wax or debris ‘stuck’ superiorly on the pars flaccida) or effusions in the middle-ear cleft may also be apparent. A conductive hearing deficit

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Figure 1: Wax impaction.

Figure 2: Bony exostosis.

Figure 3: Normal tympanic membrane.

Table 1: Medications and chemicals known to be ototoxic Drug class or Example chemical agent

Comment

Aminoglycoside Gentamicin, antibiotics tobramycin, amikacin

More likely with prolonged course or high doses and in people with renal impairment. May also cause vestibular damage Reversible dose-related hearing loss. More likely in people with renal impairment Hyperpolarisation of hair-cell membranes and raised auditory thresholds Reversible sensorineural hearing loss Documented ototoxic potential Documented ototoxic potential

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Cisplatin

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Aspirin

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Phenytoin, beta blockers, quinine Arsenic, cobolt, lead, lithium, mercury, thorium Cyanide, benzene, May be ototoxic aniline dyes, iodine, carbon tetrachloride Toluene, styrene May be ototoxic

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Table 2: Medical conditions associated with sensorineural hearing loss Aetiology

Example

Hereditary

Alport syndrome, Usher syndrome

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Diabetes, hypertension, Paget’s disease

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Viral, meningitis, syphilis

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Head injury, barotrauma, noise induced

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Polyarteritis nodosa, HIV/AIDS

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Multiple sclerosis

Neoplasm

Acoustic neuroma

Unknown

Ménière’s disease

| Australian Doctor | 31 August 2007

in the presence of an otherwise normal-appearing external auditory canal and tympanic membrane (figure 3) is usually due to otosclerosis. With the exception of a sensorineural hearing loss that occurs as part of an underlying genetic disorder or medical condition (table 2), sensorineural causes are usually not associated with external physical signs. Screening tests, such as freefield audiometry (the ‘whisper test’), can be conducted in the consulting rooms without the need for special equipment and may detect hearing impairment. If a patient is unable to hear a whisper at half a metre, it is likely they will have hearing-level thresholds of 25dB or worse. A more practical method of screening for hearing loss is to assess how well the patient hears instructions given by you (delivered in a normal conversational voice) as they enter the quiet confines of the consulting room. Appropriately performed Rinne’s and Weber’s tests using a 256Hz or 512Hz tuning fork can help determine the type of hearing loss. Care should be taken not to strike the tuning fork too hard or against a hard object, as this may produce overtones and give false results. Before performing the tests it is a good idea to ask the patient which ear they think is the better hearing one. This ear should be tested first. The simplest way of performing Rinne’s test is to gently strike the fork against your knee or elbow, and then place it on the patients’ mastoid process and ask the patient if they can hear it (figure 4A). The tuning fork should then be moved to the front of the ear and held about 2.5cm from the external auditory meatus, with the tines of the fork parallel to the ear (figure 4B). The patient is then asked which sound is louder, the tuning fork in front of or behind the ear. Rinne’s test is positive if air conduction is better than bone conduction, as is the case in a ‘normal’ ear. A conductive deficit is present if bone conduction is louder than air conduction (a negative Rinne’s test). Rinne’s test has a high specificity for conductive hearing loss, but a low sensitivity. If using a 512Hz tuning fork, there needs to be at least a 30dB air-bone gap for Rinne’s test to be accurate. Weber’s test is performed by striking the tuning fork again, this time placing it on the patient’s forehead (figure 5) (the bridge of the nose or apex of the skull may also be used) and asking the patient where they hear the sound, cont’d page 32

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Figure 4A: Rinne’s test. Holding the tuning fork on the mastoid process.

Figure 4B: Rinne’s test. Correct technique holding the tines of the fork parallel to the ear and (below) incorrect technique.

Figure 5: Weber’s test.

Bone conduction correct Figure 6: Air conduction masking with Barany box.

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How to treat – hearing loss in adults Figure 7: Audiograms. A: Normal.

B: Conductive hearing loss.

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ductive loss, bone conduction thresholds can also be tested. Masking is sometimes applied to the contralateral ear to give a more accurate result in the test ear. All this information is recorded on the audiogram and is important in interpreting the results of the hearing test. Standard symbols are used in audiology and are shown in figure 7. To be able to discriminate speech, people need to be able to hear sounds in the 500Hz to 3kHz frequency range. A person is considered to have normal hearing if they can detect sounds of ]

not notice much improvement in their hearing, compared with someone with a severe or profound hearing loss after treatment or aiding. The pattern of hearing loss on audiological testing can help determine the underlying cause of hearing loss. Presbyacusis, the progressive hearing loss associated with age, has a downwards-sloping line across the higher frequencies (figure 7C). Noise-induced hearing loss also shows a characteristic pattern of impaired hearing across the 4-6kHz range, recovering to a variable degree at 8kHz (figure 7D). Serial audiograms may be used to monitor the progression of hearing impairment in patients with potentially reversible causes of conductive hearing loss, who are not keen for surgical intervention. Tympanometry is often also performed as part of audiometry testing, to measure the compliance of the tympanic membrane and give an indication of the condition of the tympanic membrane and middle-ear cleft. A normal tympanogram is shown in figure 8A. Patients with middleear effusions have flat (type B) tympanograms (figure 8B), while those with eustachian tube dysfunction have a curve that is shifted to the left (type C tympanogram, figure 8C).

Common causes of hearing loss in adults Noise-induced hearing loss

NOISE-induced hearing loss due to exposure at work, recreation or in the home is one of the most common causes of hearing impairment worldwide. Although not all people exposed to loud noise develop noise-induced hearing loss, there is a strong correlation between prolonged exposure to noises >85dB and hearing loss. People employed in industrial workplaces and wearing no hearing protection are exposed to noises in the 90100+ dB range, with some hand-operated machinery producing noise up to 120dB. The effect of such daily exposure over several years is cumulative and can result in permanent damage to the

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auditory nerve. It can be avoided by use of well-fitting earmuffs or earplugs, which reduce the sound intensity levels by 15-25dB on average, usually bringing the noise thresholds back to an acceptable 85dB. As a rule, for every 3dB increase over 85dB, the maximum acceptable time to be exposed to the noise decreases by half. For example, in an 88dB environment a worker has a maximum exposure time of four hours, and two hours in a 91dB environment. Physical examination of the patient with noiseinduced hearing loss is unremarkable, and the audiogram has a characteristic appearance (figure 7D). Hearing aids may be of benefit in correcting the hearing loss. Patients should

| Australian Doctor | 31 August 2007

Figure 9: Sensorineural hearing loss.

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also be advised that their ears have been shown to be susceptible to noise damage and that they should wear ear protection in other noisy environments, such as motor racing or rock concerts. Cotton wool placed in the ear is no substitute for quality, well-fitting, personal protective equipment that complies with Australian Safety Standards. If noise-induced hearing loss is due to occupational factors, patients may wish to obtain legal advice as to their possible entitlement to compensation, although this is not always easy to prove.

Presbyacusis Presbyacusis is the progressive, symmetrical high-frequency hearing loss that occurs with age. It is not clear why some people develop presbyacusis while

others retain normal hearing, and we cannot predict who will be affected. Patients often complain of reduced speech discrimination, particularly in noisy environments, in addition to deafness itself. Presbyacusis is sensorineural in origin, and its audiogram is diagnostic (figure 7C). Patients with presbyacusis benefit from hearing aids. In particular, older patients who have not done well with conventional analogue hearing aids should be encouraged to be reassessed for digital hearing aids, which can be individually programmed and generally give better patient satisfaction rates.

Sudden-onset sensorineural hearing loss Sudden-onset sensorineural hearing loss is defined as an

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abrupt or rapidly progressive hearing loss of at least 30dB in three contiguous frequencies (figure 9). It is usually unilateral and may be associated with tinnitus. Sudden-onset sensorineural hearing loss is believed to be viral in origin; however, it may occasionally be due to vascular disease, autoimmune disease or neurodegenerative diseases. Physical examination is unremarkable. Traditionally, high-dose oral steroids (prednisolone 1mg/kg for five days in patients with no contraindications to steroids) have been given to speed up recovery. More aggressive treatment, such as the intra-tympanic injection of steroids, is advocated by a minority of otologists but is not standard practice. Studies suggest that 5065% of people will spontaneously recover without any treatment and, despite numerous studies and a Cochrane review, there is no conclusive evidence to prove that steroids improve the outcome. Despite this, because of the devastating effect of a persistent loss, most otologists still recommend a short course of steroids. In patients for whom steroids are not contraindicated and who have presented promptly for assessment (ideally within the first 24-48 hours), an oral course of prednisolone is recommended, and a phone call for urgent review and audiological testing made to the nearest ENT unit.

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Figure 10: Otitis media with effusion.

Figure 11: Cholesteatoma.

Figure 12: Traumatic perforation of the tympanic membrane.

Figure 13: A: Chronic suppurative otitis media. B: Chronic dry otitis media. A

Acoustic neuroma Acoustic neuromas are rare, benign slow-growing tumours of the auditory nerve that most commonly present with a unilateral hearing loss. They are often asymptomatic but if large enough they may present with imbalance or facial weakness due to compression of the facial or vestibular nerve within the internal auditory canal. All patients with a unilateral sensorineural hearing loss on audiological testing must be referred to an ENT surgeon for review to exclude an acoustic neuroma. Convincing, unilateral persistent tinnitus is also a rare indication for an acoustic neuroma screen. Most acoustic neuromas are identified while still small and asymptomatic and are monitored with MRI scans on a yearly basis. Active treatment is either stereotactic radiosurgery or surgical removal.

Conductive hearing loss Chronic otitis media with effusion

While far more common in children than in adults, some

B

adult patients do present with reduced hearing and on examination may be found to have an effusion (figure 10) Chronic otitis media with effusion (OME) is defined as a persistent effusion lasting more than 12 weeks. In most patients (children and adults alike) the effusion will improve and disappear completely with time. In adults OME is most likely to be due to associated rhinosinusitis or other nasal pathology leading to secondary eustachian tube dysfunction. Barotrauma caused by diving or air travel may also precipitate OME.

Resolution of OME secondary to rhinosinusitis or other nasal pathology can be hastened by use of topical nasal corticosteroids (eg, mometosome, budesonide) to control the underlying disease process. Topical decongestants should be avoided or at least limited to a short course (maximum three days) to avoid rebound nasal congestion and exacerbation of symptoms. In addition, the patient can be taught the Valsalva or Frenzel manoeuvres, which help to open the nasopharyngeal opening of the eustachian tube and assist with drainage of middle-ear fluid. The Frenzel manoeuvre is a modification of the Valsalva, in which the patient swallows while simultaneously performing the Valsalva manoeuvre. Adults with a middle-ear effusion lasting more than 12 weeks must be referred to an otolaryngologist for review to exclude a nasopharyngeal tumour obstructing the eustachian tube orifice. For a persisting effusion (with or without eustachian tube dysfunction) the patient may be offered a myringotomy and grommet insertion to restore middle-ear ventilation, improve hearing and promote resolution of the effusion. Patients with OME who fly are at risk of barotrauma. This risk tends to be less in patients whose middle ears are completely filled with fluid (as there is no room for gases to expand or contract), compared with those who have evidence of air-fluid levels or air bubbles in the middle ear. Ideally patients with an URTI and evidence of an effusion should be advised not to travel because of the risk of barotrauma. However, there are some simple preventive measures patients can take such as: ■ Chewing gum or yawning on descent. ■ Valsalva and Frenzel manoeuvres. ■ Topical nasal decongestants just before take-off and five minutes before decent begins. ■ Use of specialised occlusive ear plugs that allow for the slow equalisation of pressure between the external environment and middle ear. Patients who travel frequently and experience repeated bouts of barotrauma may benefit from myringotomy and grommet insertion.

Cholesteatoma Cholesteatoma is defined as the presence of squamous epithelium in the middle ear or mastoid cavity. It is thought to arise from a com-

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bination of factors, including tympanic membrane retraction due to eustachian tube dysfunction, and chronic inflammation of the middle ear. Cholesteatomas are most commonly found in the superior part of the tympanic membrane (pars flaccida), although the pars tensa may occasionally be involved. A patient with a cholesteatoma presents with hearing loss and often recurrent purulent ottorrhoea. There may also be associated tinnitus. If the cholesteatoma is extensive it may also produce imbalance due to labyrinthine erosion, or a facial nerve palsy from inflammation or compression of the nerve. On otoscopy a cholesteatoma is characterised by a retracted pocket of tympanic membrane filled with squamous epithelium, which often has a pearly appearance (figure 11). The cholesteatoma may be hidden behind a wax plug on the tympanic membrane, which requires gentle ear toilet to remove. This may need to be performed under direct vision with a microscope and suction equipment by an otolaryngologist. Left untreated, cholesteatomas continue to grow and invade the middle-ear structures and can lead to bony erosion of the ossicular chain, intracranial extension, abscess formation or cranial nerve defects. The risk of these potentially life-threatening complications means that all patients with suspected cholesteatoma must be referred to an otolaryngologist for assessment and discussion of surgical (or occasionally conservative) treatment options.

Tympanic membrane perforations Traumatic perforations of the tympanic membrane are usually associated with a blow to the ear or inadvertent placement of a foreign body in the ear canal. They present with bloody otorrhoea and a conductive hearing loss. The history is diagnostic and on examination there is usually dried blood in the external auditory canal, with a perforation visible in the pars tensa of the tympanic membrane (figure 12). Traumatic perforations frequently heal completely within a few weeks and require no special intervention. However, it is important to advise the patient to take precautions with water and to not try to clean their ear, as this may introduce bacteria into the middle ear, with subsequent infection. If the perforation persists at six

weeks, it is unlikely to close spontaneously. Patients with a long or recurrent history of middleear infections may have chronic tympanic membrane perforations associated with a conductive hearing deficit. There may also be a history of recurrent purulent discharge from the affected ear (active chronic otitis media [figure 13A]) or the ear may be dry (inactive chronic otitis media [figure 13B]). These patients will also benefit from referral to an otolaryngologist to discuss surgical options to close the perforation.

Otosclerosis Otosclerosis tends to affect people at an earlier age than presbyacusis. It is more common in women and its typical onset is during the third or fourth decade. It presents as a slowly progressive hearing loss that may be unilateral or bilateral. Bilateral losses are often asymmetrical. There may be a positive family history of otosclerosis, and women may find that the hearing loss worsens when they are pregnant or using oestrogen therapy (eg, the oral contraceptive pill). The underlying pathological process is restricted to the otitic capsule and results in fixation of the stapes footplate, leading to a conductive deafness. Otoscopic examination is normal, and serial audiograms show a progressive hearing loss. Patients with otosclerosis should also be referred to an ENT surgeon for consideration of a stapedectomy to treat the hearing loss.

When to refer to an otolaryngologist Hearing loss in adults is most commonly due to presbyacusis or noise exposure and may be managed appropriately in the community by GPs in association with audiologists. However, any of the following features in the history and/or on physical examination of the patient with hearing loss necessitate referral to an otolaryngologist for further investigation: ■ A chronically discharging ear. ■ A unilateral or asymmetrical hearing loss. ■ A persistent middle-ear effusion. ■ A suspicion of cholesteatoma. ■ Postural imbalance or vertigo. ■ Large exostosis. ■ A conductive hearing loss and normal physical examination (for otosclerosis). ■ Non-healing tympanic membrane perforation. ■ Facial weakness. ■ Unilateral or pulsatile tinnitus.

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How to treat – hearing loss in adults Treatment options

Summary

Prevention

hearing loss and whether the hearing loss is unilateral or bilateral, some patients may have deafness that is amenable to surgical correction. With all surgery to the ear there is the potential to cause irreversible deafness in the operated ear, and this must be taken into consideration before embarking on surgery.

ADEQUATE, well-fitting hearing protection is essential for preventing noiseinduced hearing loss and should be worn both in the workplace and during activities or hobbies that involve exposure to loud noises. Avoiding further exposure to medications known to be ototoxic is also important in patients with hearing loss.

Cochlear implants Hearing aids For many patients the fitting of an appropriately configured hearing aid results in a significant improvement in hearing. Patients with a moderate to severe hearing impairment subjectively benefit more from hearing aids than those with only moderate impairment. The audiologist plays an important role in choosing the most appropriate type of hearing aid for the needs of a given patient. In general, patients with low-tone hear-

ing loss receive the greatest quality-of-life benefit from hearing aids, although music lovers with high-tone losses also benefit. The circumstances of each individual patient need to be assessed before a decision on a hearing aid trial.

Surgery Depending on the underlying aetiology, the degree of

First introduced more than 20 years ago, cochlear implants were initially limited to post-lingually (after learning to speak) deaf adults with severe to profound bilateral hearing loss who derived little benefit from hearing aids. As technology and surgical expertise improves, more and more patients are now being considered for cochlear implants. Cochlear implants are designed to bypass the nonfunctioning inner-ear hair

cells and convert acoustic impulses to electrical signals that stimulate the auditory nerve directly. The signal is then transferred to the auditory cortex in the usual manner, resulting in a marked improvement in hearing. Patients likely to benefit most from cochlear implants are those with bilateral severe to profound hearing loss, regardless of age or duration of hearing loss. However, surgery does entail a 3-4 hour anaesthetic and a two-day hospital stay, which require the patient to be relatively fit. Some dizziness or unsteadiness on standing is expected in the postoperative period, although this settles for the most part in the first week or so. The cochlear implant is turned on 3-4 weeks later and a complex program of audiological rehabilitation then begins.

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Hearing loss is common and often goes undiagnosed or untreated.

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Screening for risk factors for hearing loss may allow early intervention and prevent further impairment (avoiding certain medications, noise exposure, etc).

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Otoscopy is an important part of the assessment of hearing loss and often leads to the correct diagnosis.

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Appropriately performed and interpreted tuning fork tests are useful in identifying the underlying type of hearing loss in the absence of easily assessable audiology.

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Audiometry identifies type and degree of hearing loss and helps determine the most appropriate treatment (observation, aiding or surgery).

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The most common causes of hearing loss in Australia are noise induced and presbyacusis — both are amenable to hearing aids.

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Consider referral to an otolaryngologist when a patient presents with hearing loss and there are unusual features on the history or examination findings.

Authors’ case studies

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| Australian Doctor | 31 August 2007

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HR, 45 and with no significant medical history apart from a history of smoking a pack of cigarettes a day for 20 years, presents to her GP in a distressed state. She has woken up this morning “completely deaf” in the right ear. There is no history of preceding infection, air travel, head trauma or ototoxic medication use. On examination there is minimal wax in the external auditory canal, and a normal tympanic membrane can be visualised bilaterally. The GP performs a screening hearing test, which confirms a loss in the right ear, followed by Weber’s and Rinne’s test, which confirm the presence of a sensorineural hearing loss. After discussion with the on-call ENT doctor at the nearest hospital, HR is started on a course of oral prednisolone (1mg/kg). She is seen in the ENT outpatient clinic the next day and reports no significant improvement in her hearing. Pure-tone audiology shows a 60dB right-sided sensorineural hearing loss. The steroids were continued for 10 days and she was advised to rest at home. Arrangements were made to review HR in the ENT clinic every 48 hours and she was reassured that many cases spontaneously resolve. A week later there was some improvement in hearing, which was confirmed on audiological testing. Her recovery was monitored through the ENT clinic and at two months she had almost fully recovered. However, an asymmetrical sensorineural loss persisted on pure-tone audiometry. An MRI of the right internal acoustic meatus excluded the presence of an acoustic neuroma. She was fitted with a unilateral digital hearing aid, which provided some limited benefit in stereo sound perception.

Figure 14: A: HN’s otosclerosis before surgery. B: Stapes prosthesis. C: Postoperative audiogram.

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Conductive deafness in an otherwise healthy woman HN is a 37-year-old mother of two. She has no significant past medical history of note and presents with a gradual onset of deafness, worse on the left, over several years, which had worsened during her last pregnancy. There is no family history of hearing impairment, and HN does not take any regular medications

ness. She is wondering what the cause is and if anything can be done about it. Physical examination, including otoscopy was unremarkable. A pure-tone audiogram was obtained (figure 14A) and showed a bilateral, asymmetrical, moderate to severe conductive hearing loss, which was worse on the left. A diagnosis of otosclerosis was made and the pathogenesis and likely outcome of the condition discussed with HN. Treatment options were also discussed, including observation, hearing aids and surgical correction by stapedectomy. Given her age, degree of hearing impairment and desire to avoid the use of hearing aids if possible, the decision was made to proceed with surgery on the left ear (figure 14B). Postoperatively the patient reported a marked improvement in hearing with the left ear, which was confirmed on audiological testing (figure 14C).

Hearing loss in an older man

and has not been exposed to ototoxic medications in the past. HN was aware that her hearing was not as good as her peers, and she now reports that the hearing loss is worsening and has started to become intrusive. She finds it difficult to hear in noisy environments, which is starting to interfere with her ability to work, and her family members have also started to complain about her deafwww.australiandoctor.com.au

BB, 73, lives independently with his wife in the community. His only medical problems are hypertension and diet-controlled prediabetes. He is on an ACE inhibitor. BB’s wife reports he has been deaf for years, and indeed he admits he has trouble hearing in a range of different situations — watching television, using the phone and in shopping centres. He has started withdrawing from social situations because he is embarrassed about constantly asking people to speak louder or to repeat themselves. On examination BB has impacted wax occluding both external auditory canals, which is removed by microsuction toilet of the ears. The remainder of the otoscopic examination is normal. A pure-tone audiogram is performed, which shows a presbyacusis pattern of hearing loss (figure 7C, page 32). He is referred to an audiologist for fitting and provision of hearing aids.

Online resources ■

ENT UK: www.entuk.org ■ ENT Net: www.entnet.org/health info

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How to treat – hearing loss in adults GP’s contribution

DR ANN PARKER Bowral, NSW

Case study JR, 51, presented with a history of sudden onset of hearing loss in the early hours of that morning. She had woken with vertigo while lying still and loud tinnitus. Over subsequent hours the tinnitus had persisted and her hearing was poor on the left side. She had no further vertigo but felt “fuzzy” in the left side of her head and unable to think clearly. She had no history of any other hearing problem, head injury or neurological symptom. Her work is office based and she had had no real exposure to loud noises.

She is an ex-smoker with well-controlled hypertension on telmisartan 80mg daily, and no history of other vascular or autoimmune conditions. There is a family history of presbyacusis in her mother. On examination, Rinne’s and Weber’s tests indicated a sensorineural cause, with the Weber’s test localising to the right ear. Vestibular system and ear examinations were normal. She was diagnosed with sudden-onset sensorineural hearing loss and started on prednisone 50mg for 10 days, then 25mg for a further two weeks. After referral to an ENT surgeon she had an MRI that showed some white-matter ischaemia, which was thought to be unrelated. Her audiogram 10 days after onset showed moderate highfrequency loss. Her hearing has improved to about 75% of normal and tinnitus remains but is no longer at distressing levels.

Questions for the authors How common is sudden-onset sensorineural hearing loss? In 25 years in practice I had not come across this condition, unless it may have been missed if patients had not presented with the complaint at the time. Sudden-onset sensorineural hearing loss is uncommon and the incidence is quoted in the American literature to be in the order of 5-20 per 100,000 people. It is thought that the actual incidence is higher, but that many cases go unreported. In our teaching hospital we have had five cases this year already. Does a prolonged course of prednisone, such as three

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2. Gina, 42, presents complaining of reduced hearing in her left ear since waking this morning. She feels otherwise well. Which THREE conditions would you consider in the differential diagnosis for Gina’s presentation? ❏ a) Wax in the external auditory canal ❏ b) Otosclerosis ❏ c) Sudden-onset sensorineural hearing loss ❏ d) Middle-ear effusion after an URTI 3. You examine Gina. Which TWO statements about your physical examination are correct? ❏ a) Inability to hear a whisper at a distance of half a metre suggests Gina has a hearing loss of 25dB or worse ❏ b) The correct tuning fork to use for performing Rinne’s or Weber’s tests is 128Hz ❏ c) If Gina has a conductive deafness in her left ear, her Rinne’s test will be negative in this ear ❏ d) If Gina has a sensorineural deafness in her left ear on Weber’s test the sound will be heard in her left ear

What is the nature of vascular causes of sudden-onset sensorineural hearing loss? While the exact aetiology of vascular causes of suddenonset sensorineural hearing loss is unknown, we do know that the cochlea is an end organ with little collateral blood supply, making it vulnerable to damage from vasospasm, hypotension,

4. You refer Gina for an audiogram and tympanogram. Which TWO statements about these tests are correct? ❏ a) Normal hearing is defined as the ability to hear sounds of )5-10dB across the range of frequencies ❏ b) If an air-bone gap is found it indicates that Gina has a sensorineural hearing loss ❏ c) If Gina has a middle-ear effusion she will have a type B tympanogram ❏ d) To hear speech, people need to be able to hear sounds in the 500Hz to 3kHz range 5. Ron, 67, is becoming increasingly deaf in both ears. He believes it is due to noise exposure in his previous work as a boiler-maker. Which TWO statements about noise-induced hearing loss are correct? ❏ a) All people who have worked in loud environments, such as Ron, will have some noise-induced hearing loss ❏ b) Ear protection needs to fit well and be able to reduce the sound level to )85dB to prevent noise-induced deafness ❏ c) Investigations show a high-frequency sensorineural hearing loss and a type A tympanogram ❏ d) Hearing aids are of little use in this condition 6. Lien, 72, presents as a new patient to your practice for a prescription of her regular medications. You notice that she has

emboli or thrombosis, with resulting ischaemia of the cochlea nerve and associated deafness. Established risk factors for ischaemic heart disease (such as hypercholesterolaemia) have not been confirmed in patients with sudden-onset sensorineural hearing loss; however, the presentation with sudden hearing loss is felt to be consistent with a vascular insult.

General questions for the authors Do you think we will see fewer cases of cholesteatoma in future because of better treatment of middle-ear disease in children? As a specialty we have been treating middle-ear disease earlier and more aggressively over the past 2-3 decades than previously, to address hearing and speech/language development concerns. As a consequence the number of cholesteatomas we are seeing has probably reached a plateau.

Should patients with a traumatic tympanic membrane perforation be given any prophylactic antibiotics orally or as ear drops? I understand now that aminoglycoside drops may not be safe in these circumstances. Traumatic tympanic membrane perforations do not necessarily require prophylactic treatment. In the setting of an actively discharging ear (acute otitis media, barotraumas, etc), topical antibiotic drops may lead to faster resolution of symptoms. Perforations due to noise or head injury, for example, are often dry and do not require antibiotics; however, patients should be advised to keep their ear dry and not attempt to clean their ear with cotton buds that may introduce bacteria and subsequent infection into the middle-ear cleft. When there is a perforation, ciprofloxacin drops should be used to avoid ototoxicity, which can occur with topical antibiotics.

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Hearing loss in adults — 31 August 2007 1. Which TWO statements about hearing loss in Australia are correct? ❏ a) Nearly 20% of people aged over 15 are affected ❏ b) The condition is more common in elderly women than men ❏ c) Two of the most common causes are presbyacusis and noise-induced hearing loss ❏ d) In patients aged over 55 the incidence rises to over 60%

weeks as recommended for this patient, have any benefit over a five-day course? Conclusive evidence of the benefit of steroids in treating sudden-onset sensorineural hearing loss is not available, with more research needed. Historically a five-day course of steroids has been used, with some studies advocating a slightly longer tapered course (10-12 days). The side effects of prolonged oral steroid medication must be considered before embarking on a treatment regimen that currently has limited evidence of efficacy.

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difficulty hearing you and she says she has been aware of reduced hearing for several years. Which THREE factors in the history would you consider as possibly related to her deafness? ❏ a) She suffers from Paget’s disease ❏ b) She was given aminoglycoside antibiotics for a septic episode four years ago ❏ c) Her brother has kidney failure and deafness ❏ d) She takes regular NSAIDs for osteoarthritis 7. Roman, 52, presents complaining of reduced hearing and a smelly discharge from his right ear. The clinical examination suggests Roman has a cholesteatoma. Which THREE statements about this condition are correct? ❏ a) Typical otoscopy findings include a retraction pocket in the superior tympanic membrane, filled with pearly-looking material ❏ b) As cholesteatoma is a slow-growing tumour and complications are rare, referral is not necessary ❏ c) Eustachian tube dysfunction is thought to be one of the factors involved in formation of cholesteatoma ❏ d) Cholesteatoma causes a conductive hearing loss, which may be associated with tinnitus 8. Elsa, 40, presents with a blocked feeling and reduced hearing in her left ear for the past two weeks. On examination she has a middle-ear effusion. Which TWO statements

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about middle-ear effusion in adults are correct? ❏ a) Effusions in adults are unlikely to resolve on their own, so patients should be promptly referred for myringotomy ❏ b) Barotrauma from diving or air travel can precipitate an effusion ❏ c) Regular use of decongestant nasal sprays is the best treatment for middle-ear effusion ❏ d) Patients with evidence of an air-fluid level on otoscopy should be counselled against flying 9. Which TWO conditions cause a conductive hearing loss? ❏ a) Acoustic neuroma ❏ b) Otosclerosis ❏ c) Tympanic membrane perforation ❏ d) Hearing loss due to high-dose salicylates 10. Which THREE statements about the timing of, and reasons for, referral to an otolaryngologist are correct? ❏ a) Adults with chronic otitis media with effusion should be referred if the problem has not resolved after 12 weeks ❏ b) Patients with sudden-onset sensorineural hearing loss should be seen within two weeks ❏ c) Patients with a unilateral sensorineural hearing loss should be referred to exclude acoustic neuroma ❏ d) Patients with a conductive hearing loss and a normal otoscopic examination should be referred for investigation of otosclerosis

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HOW TO TREAT Editor: Dr Marcela Cox Co-ordinator: Julian McAllan Quiz: Dr Marcela Cox

The mark required to obtain points is 80%. Please note that some questions have more than one correct answer. Your CPD activity will be updated on your RACGP records every January, April, July and October.

NEXT WEEK The next How to Treat, on adolescent gynaecology, aims to help GPs differentiate normal variations of puberty from true gynaecological problems, so appropriate advice can be given to young women and their families, and referral for endocrine or gynaecological assessment can occur when needed. The author is Professor Jenny A Batch, director of endocrinology and diabetes, Royal Children’s Hospital, Herston, Queensland.

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| Australian Doctor | 31 August 2007

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