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Primary Care Update Brief Summaries for Clinical Practice

www.Consultant360.com292  CONSULTANT APRIL 2012

Sudden Hearing Loss:

Guideline for Diagnosis and Management

Sudden hearing loss can befrightening for patients—and challenging for clini-cians. One of the manycauses is sensorineural

hearing loss (SNHL); early recogni-tion and treatment may improve thelikelihood of hearing recovery.

Recently, the American Acade-

my of Otolaryngology–Head andNeck Surgery Foundation pub-lished new guidelines on the diag-nosis and management of suddenhearing loss in adults; the focus ofthe recommendations is on suddenSNHL.1 Highlights of these guide-lines are presented here.

BACKGROUND

 Working definition. The guide-line panel defined sudden SNHL as

a hearing loss of at least 30 dB thataffects at least 3 contiguous fre-quencies and occurs over a 72-hourperiod.1 An abnormality of the co-chlea, auditory nerve, or higher as-pects of central auditory perceptionor processing is involved.

Causes. Up to 90% of cases ofsudden SNHL are idiopathic at initialpresentation (  Table ); however, vas-cular, viral, or multiple causes aretypically implicated.2 Among thecauses of sudden SNHL that need tobe recognized and addressed earlyare vestibular schwannoma (acousticneuroma), stroke, and malignancy.3

Epidemiology. The incidenceof sudden SNHL is reported to befrom 5 to 20 per 100,000 population;some estimates are as high as 160per 100,000.4,5 In the United States,about 4000 cases occur each year.

EVALUATIONHistory. The first step is to dis-

tinguish SNHL from conductivehearing loss (CHL) in a patient who

presents with sudden hearing loss. Ask the patient about recent trau-ma, external ear and canal pain, eardrainage, fever, and other systemicsymptoms.1 Patients with suddenSNHL often report tinnitus, ear full-ness or pressure, and vertigo; how-ever, these symptoms may also beassociated with CHL.

Physical examination. Inspectthe ear canals and visualize the tym-panic membranes. Causes of CHL in-clude cerumen impaction, middle earfluid, otitis media, foreign bodies, per-forated tympanic membrane, canaledema from otitis externa, otosclero-sis, trauma, and cholesteatoma.1 Theotoscopic examination typically re- veals abnormalities in patients withCHL, while otoscopic findings areusually normal in those with SNHL.

 Traditionally, the Weber andRinne tuning fork tests have beenused to distinguish SNHL from CHL. Although the results of these testscan be misleading,6,7 the guidelinepanel recommends that tuning forktests be used to confirm audiometricfindings.

 A Weber test is per formed byplacing the fork on the patient’sforehead; look for lateralization of

sound to one side. If the soundlateralizes to the affected side, it islikely that the hearing loss is con-ductive. If the sound lateralizes tothe opposite ear, the loss is proba-bly sensorineural.

 The Rinne test is done to com-pare bone conduction with air con-duction for both ears. An abnormal

result of a Rinne test indicates a con-ductive hearing loss of at least 20 dB.Patients with presumptive sud-

den SNHL should be assessed forbilateral hearing loss, recurrentepisodes of sudden hearing loss,and focal neurologic findings. These clinical features can point toan underlying cause of the hearingloss, such as autoimmune condi-tions, metabolic disorders, bilateralMeniere disease, and certain neu-

rological disorders.Diagnostic studies.  A CT scan

of the head is not warranted duringthe initial evaluation of patients withsudden SNHL. The scan providesno useful information that would af-fect initial management, and it posessignificant risks, including radiationexposure and adverse effects of in-travenous contrast. Reserve CT forpatients with focal neurological find-

Table – Causes of sensorineural hearing loss

Cause Examples

Infectious Viral and bacterial infections (including Lyme disease)

Vascular Stroke, other thromboembolic phenomena,hypercoagulable states

Neoplastic Vestibular schwannoma, malignancy

Inflammatory Immune-mediated or in conjunction with other factors

Idiopathic –Data from Stachler RJ et al. Otolaryngol Head Neck Surg. 2012.1

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www.Consultant360.com296  CONSULTANT APRIL 2012

Primary Care Update Sudden Hearing Loss:

Guideline for Diagnosis and Management 

ings, a history of trauma, or chronicear disease.

 The guideline panel also advis-es against routine laboratory testsin patients with idiopathic suddenSNHL. A specific test may be con-sidered if the history indicates itmight be useful in identifying a po-tential cause of the hearing loss,such as drawing Lyme titers in en-demic regions.

Further workup. For patients with idiopathic sudden SNHL, orderan MRI scan, auditory brainstem re-sponse (ABR), or audiometric fol-

low-up to detect retrocochlear pa-thology. A small but significant per-centage of these patients have anunderlying lesion, most often a ves-tibular schwannoma.1 In addition,MRI can help identify other causesof sudden SNHL, such as cochlearinflammation or multiple sclerosis,or it may reveal evidence of an un-derlying cause of the sudden SNHL,such as small vessel cerebral isch-emia. The overall percentage of MRI

abnormalities directly related to sud-den SNHL ranges from 7% to 14%.8,9  Thus, MRI has the highest yield ofany diagnostic test in the setting ofsudden SNHL.1 If MRI is contraindi-cated (eg, in patients with pacemak-ers or other metallic implants), an al-ternative is a fine-cut CT scan of thetemporal bones with contrast.

 The ABR test is highly sensitivefor vestibular schwannomas that arelarger than 1 cm; however, its report-ed sensitivity for smaller schwanno-mas varies from 8% to 42%.10-12 Con-sider the ABR test for the initial eval-uation of older patients in whom theconsequences of a missed diagnosisof a small tumor may be less worri-some than in younger patients.

 While the guideline panel gen-erally recommends MRI and ABR todetect any underlying retrocochlearpathology in patients with sudden

SNHL, serial audiometry is an optionin selected patients. For those whohave some residual hearing after theinitial episode of sudden SNHL, pro-

gression of hearing loss detected onrepeated hearing tests is suggestiveof retrocochlear pathology.

MANAGEMENT

Spontaneous recovery. Somepatients recover completely withoutmedical intervention, often within thefirst 3 days; others regain their hear-ing slowly over a 1- to 2-week period. The greatest spontaneous improve-ment in hearing occurs during thefirst 2 weeks; late recovery is rare.

Corticosteroids.  For patients with idiopathic sudden SNHL, corti-

costeroids may be offered as initialtherapy. These agents have sites ofaction in the inner ear, and they areeffective in the treatment of viral, vascular, syphilitic, autoimmune, en-dolymphatic hydrops (Meniere dis-ease), and other causes of hearingloss. The recommended regimenconsists of oral prednisone given at1 mg/kg/d in a single (not divided)dose, with the usual maximum doseof 60 mg/d, and treatment duration

of 10 to 14 days. Corticosteroidtherapy seems to be most effectiveduring the first 2 weeks after the ep-isode of sudden hearing loss; littlebenefit is seen after 4 to 6 weeks.

Consider intratympanic cortico-steroid perfusion for patients in whom systemic corticosteroids areineffective. The corticosteroid maybe delivered by a needle throughthe tympanic membrane, or it maybe placed into the middle earthrough a tympanostomy tube or amyringotomy. The intratympanicroute avoids the significant adverseeffects of additional systemic corti-costeroid therapy.

Other treatments. Hyperbaricoxygen therapy may be beneficial asan adjuvant intervention if this treat-ment is started within 3 months ofthe onset of idiopathic suddenSNHL. The greatest benefit has

been seen in patients with severe toprofound hearing loss.1

 Antivirals, thrombolytics, vaso-dilators, vasoactive substances, and

antioxidants have no role in the treat-ment of idiopathic sudden SNHLbecause their effectiveness has notbeen demonstrated in this setting.1

FOLLOW-UP

 Within 6 months of the diagno-sis of idiopathic sudden SNHL, orderfollow-up audiometric evaluation. Ifthe patient’s hearing loss is perma-nent, auditory rehabilitation may berequired. Counsel patients who haveresidual hearing loss about the po-tential benefits of hearing aids andassistive listening devices.

 A list of organizations thatprovide information and supportfor patients with hearing loss canbe found on the web site of theNIH National Institute on Deafnessand Other Communication Disor-ders: http://www.nidcd.nih.gov/directory/. n

REFERENCES:1. Stachler RJ, Chandrasekhar SS, Archer SM,et al. Clinical practice guideline: sudden hearingloss. Otolaryngol Head Neck Surg. 2012;146:S1.

DOI: 10.1177/01945998124364492. Rauch SD. Clinical practice: idiopathic suddensensorineural hearing loss. N Engl J Med. 2008;359(8):833-840.3. Saunders JE, Luxford WM, Devgan KK,Fetterman BL. Sudden hearing loss in acousticneuroma patients. Otolaryngol Head Neck Surg.1995;113(1):23-31.4. Byl FM Jr. Sudden hearing loss: eight years’experience and suggested prognostic table.

 Laryngoscope. 1984;94(5, pt 1):647-661.5. Klemm E, Deutscher A, Mosges R. A presentinvestigation of the epidemiology in idiopathicsudden sensorineural hearing loss [in German].

 Laryngorhinootologie. 2009;88(8):524-527.6. Miltenburg DM. The validity of tuning fork testsin diagnosing hearing loss. J Otolaryngol. 1994;23

(4):254-259.7. Browning GG, Swan IR, Chew KK. Clinical roleof informal tests of hearing. J Laryngol Otol.1989;103(1):7-11.8. Schick B, Brors D, Koch O, Schafers M, KahleG. Magnetic resonance imaging in patients withsudden hearing loss, tinnitus and vertigo. Otol

 Neurotol. 2001;22(6):808-812.9. Cadoni G, Cianfoni A, Agostino S, et al. Magneticresonance imaging findings in sudden sensorineu-ral hearing loss. J Otolaryngol. 2006;35(5):310-316.10. Chandrasekhar SS, Brackmann DE, DevganKK. Utility of auditory brainstem response audiom-etry in diagnosis of acoustic neuromas. Am J Otol.1995;16(1):63-67.11. El-Kashlan HK, Eisenmann D, Kileny PR. Auditory brain stem response in small acoustic neu-romas. Ear Hear. 2000;21(3):257-262.12. Schmidt RJ, Sataloff RT, Newman J, Spiegel JR,Myers DL. The sensitivity of auditory brainstemresponse testing for the diagnosis of acoustic neu-romas. Arch Otolaryngol Head Neck Surg. 2001;127(1):19-22.