Key Points
- Sudden hearing loss (SHL) is a frightening symptom that often prompts an urgent or emergent visit to a clinician. This guideline update focuses on sudden sensorineural hearing loss (SSNHL), the majority of which is idiopathic and which, if not recognized and managed promptly, may result in persistent hearing loss and tinnitus and reduced patient quality of life (QOL). SSNHL affects 5–27 per 100,000 people annually, with about 66,000 new cases per year in the United States.
- SHL is defined as a rapid-onset subjective sensation of hearing impairment in one or both ears. The hearing loss in SHL may be conductive (CHL), sensorineural (SNHL), or mixed (MHL), defined as both CHL and SNHL occurring in the same ear. CHL and the conductive component of MHL may be due to an abnormality in the ear canal, tympanic membrane (‘ear drum’), or middle ear.
- Physical examination will help determine if there is obstructing cerumen or a foreign body in the ear canal, if there is a perforation of the tympanic membrane, or if there is fluid in the middle ear.
- Tuning fork testing will enable the initial treating clinician to distinguish CHL from SNHL, so that the SSNHL evaluation and management (E&M) pathway can be triggered appropriately.
- SSNHL is a subset of SHL that is: a) sensorineural in nature, b) occurs within a 72-hour window, and c) meets certain audiometric criteria.
- SNHL is sometimes referred to colloquially as ‘nerve hearing loss’ and indicates abnormal functioning of the cochlea, auditory nerve, or higher aspects of central auditory perception or processing.
- The most frequently used audiometric criterion for SSNHL is a decrease in hearing of greater than or equal to 30 decibels affecting at least 3 consecutive frequencies. Because premorbid audiometry is generally unavailable, hearing loss is often defined in relation to the opposite ear’s thresholds.
- The CPG update group acknowledges that in both clinical practice and in research studies, less stringent criteria for SSNHL are employed.
- SSNHL is often but not always accompanied by tinnitus and/or vertigo. The tinnitus may persist and may be disturbing to the patient.
- Idiopathic sudden sensorineural hearing loss (ISSNHL) is defined as SSNHL with no identifiable cause despite adequate investigation. This is the situation in 90% of patients with SSNHL and is the primary focus of this CPG update. The use of SSNHL in this document refers to ISSNHL, after the appropriate workup has been done as denoted in KAS 1 and KAS 2.
Table 1. Definitions of Common Terminology
| Sudden Hearing Loss (SHL) | A rapid-onset subjective sensation of hearing impairment in one or both ears. |
|---|---|
| Sensorineural Hearing Loss (SNHL) | Hearing loss resulting from abnormal function of the cochlea, auditory nerve, or higher aspects of central auditory perception or processing. |
| Conductive Hearing Loss (CHL) | Hearing loss resulting from a problem conducting sound waves anywhere along the route through the outer ear, tympanic membrane, or middle ear. |
| Mixed Hearing Loss (MHL) | Hearing loss resulting from both SNHL and CHL occurring in the same ear. |
| Sudden Sensorineural Hearing Loss (SSNHL) | A subset of SHL that is a) sensorineural in nature, b) occurs within a 72-hour window, and c) consists of a decrease in hearing of greater than or equal to 30 decibels affecting at least 3 consecutive frequencies. |
| Idiopathic Sudden Sensorineural Hearing Loss (ISSNHL) | SSNHL with no identifiable cause despite adequate investigation. |
| Salvage Therapy | Any therapy offered after 2 weeks from symptom onset (even if initial therapy was observation). |
Table 2. Summary of Key Action Statements (KAS)
| Statement | Action | Grade |
|---|---|---|
| 1. Exclusion of CHL | Clinicians should distinguish SNHL from CHL when a patient first presents with sudden hearing loss. | Strong recommendation |
| 2. Modifying factors | Clinicians should assess patients with presumptive SSNHL through history and physical examination for bilateral sudden hearing loss, recurrent episodes of sudden hearing loss, and/or focal neurologic findings. | Recommendation |
| 3. Computed tomography (CT) | Clinicians should NOT order routine CT of the head in the initial evaluation of a patient with presumptive SSNHL. | Strong recommendation against |
| 4. Audiometric confirmation of SSNHL | In patients with sudden hearing loss clinicians should obtain, or refer to a clinician who can obtain, audiometry as soon as possible (within 14 days of symptom onset) to confirm the diagnosis of SSNHL. | Recommendation |
| 5. Laboratory testing | Clinicians should NOT obtain routine laboratory tests in patients with SSNHL. | Strong recommendation against |
| 6. Retrocochlear pathology | Clinicians should evaluate patients with SSNHL for retrocochlear pathology by obtaining an MRI or Auditory Brainstem Response (ABR). | Recommendation |
| 7. Patient education | Clinicians should educate patients with SSNHL about the natural history of the condition, the benefits and risks of medical interventions, and the limitations of existing evidence regarding efficacy. | Strong recommendation |
| 8. Initial corticosteroids | Clinicians may offer corticosteroids as initial therapy to patients with SSNHL within 2 weeks of symptom onset. | Option |
| 9a. Initial therapy with hyperbaric oxygen therapy (HBOT) | Clinicians may offer, or refer to a clinician who can offer, HBOT combined with steroid therapy within two weeks of onset of SSNHL. | Option |
| 9b. Salvage therapy with HBOT | Clinicians may offer, or refer to a clinician who can offer, HBOT combined with steroid therapy as salvage within one month of onset of SSNHL. | Option |
| 10. Intratympanic steroids for salvage therapy | Clinicians should offer, or refer to a clinician who can offer, intratympanic (IT) steroid therapy when patients have incomplete recovery from SSNHL 2–6 weeks after onset of symptoms. | Recommendation |
| 11. Other pharmacologic therapy | Clinicians should NOT routinely prescribe antivirals, thrombolytics, vasodilators, or vasoactive substances to patients with SSNHL. | Strong recommendation against |
| 12. Outcomes Assessment | Clinicians should obtain follow-up audiometric evaluation for patients with SSNHL at the conclusion of treatment and within six months of completion of treatment. | Recommendation |
| 13. Rehabilitation | Clinicians should counsel patients with SSNHL who have residual hearing loss and/or tinnitus about the possible benefits of audiological rehabilitation and other supportive measures. | Strong recommendation |
Diagnosis
- The distinction between SSNHL and other causes of SHL is one that should be made by the initial treating health care provider. (KAS 1) — by history, physical examination, and use of tuning fork tests (see Table 2)
- Nonidiopathic causes of SSNHL must be identified and addressed during the course of management. (KAS 2)
- Notable among these are vestibular schwannoma (acoustic neuroma) and stroke.
- Up to 90% of SSNHL, however, is idiopathic at presentation and is presumptively attributed to vascular, viral, or multiple etiologies.
- The most frequently used audiometric criterion is a decrease in hearing of ≥30 dB, affecting at least 3 consecutive frequencies.
- It is common clinical practice to treat patients with SSNHL that is of less severity than this definition according to the principles of the clinical practice guideline.
- Because premorbid audiometry is generally unavailable, hearing loss is defined as related to the opposite ear’s thresholds.
Figure 1. SHL Guideline Key Action Statements
Table 3. Recommended Technique for Weber and Rinne Testing
| Weber test | Rinne test |
|---|---|
| 1. Vibrate the tuning fork by striking it on your (covered) elbow or knee, not on a hard metallic or wooden surface. | 1. Vibrate the tuning fork by striking it on your (covered) elbow or knee, not on a hard metallic or wooden surface. |
| 2. Place vibrating tuning fork (256 or 512 Hz) at midline of forehead or on maxillary teeth (not false teeth) | 2. Place vibrating tuning fork (256 or 512 Hz) over the mastoid bone of one ear, then move the tuning fork to the entrance of the ear canal (not touching the ear) with the tines directed toward the ear. |
| 3. Ask where the sound is heard; it is normal to hear at the midline or ‘everywhere’ | 3. The sound should be heard better via air conduction (at the entrance to the ear canal) |
4. If the sound lateralizes to one ear, then:
| 4. If the sound is heard better by bone conduction in the same ear, then there is CHL in that ear. 5. If the sound is heard better by bone conduction but in the opposite ear, there is SNHL in the test ear. 6. Repeat for the other ear. |
Table 4. Some Symptoms and Signs Suggestive of Non-Idiopathic Sudden Sensorineural Hearing Loss
| Sudden onset of bilateral hearing loss |
| Antecedent fluctuating hearing loss on one or both sides |
| Concurrent severe bilateral vestibular loss with oscillopsia |
| Gaze evoked or downbeat nystagmus |
| Concurrent eye pain, redness, lacrimation, and photophobia |
| Focal neurological symptoms or signs such as headache, confusion, diplopia, dysarthria, focal weakness, focal numbness, ataxia, facial weakness |
| Recent head trauma |
| Recent acoustic trauma |
| Recent barotrauma |
Table 5. Selected Conditions That May Be Associated With Bilateral SSNHL
| Cause | Other Features |
|---|---|
| Infection (viral including herpes simplex virus [HSV], varicella zoster virus [VZV], human immunodeficiency virus [HIV] and others; bacterial; mycoplasma; Lyme; tuberculosis; syphilis; fungal) | Headache, fever, other cranial nerve palsies, abnormal cerebrospinal fluid (CSF) commonly seen in meningitis; Pinna or ear canal vesicles and facial weakness are often seen in VZV. (Ramsay Hunt Syndrome/Herpes Zoster Oticus) |
| Autoimmune inner ear disease | Hearing fluctuation, vertigo |
| Ototoxic Medication | Vestibular loss, oscillopsia |
| Trauma | Temporal bone fracture with possible Battle’s sign; cochlear concussion without visible fracture; barotrauma |
| Lead poisoning | Learning disabilities, other stigmata of lead poisoning |
| Genetic Disorders | May be syndromic or nonsyndromic and may present later in life |
| Mitochondrial Disorders including MELAS (Metabolic Encephalopathy, Lactic Acidosis and Stroke-like episodes) and others | Confusion, stroke like spells, elevated lactate, MRI white matter changes; others with variable phenotypes |
| Stroke | Vertigo, dysarthria, facial weakness, ataxia, nystagmus, unilateral numbness, abnormal CT or MRI or MR angiogram of the vertebrobasilar vasculature |
| Cogan’s syndrome | Non-syphilitic interstitial keratitis of the cornea, hearing loss, vertigo |
| Neoplastic (neurofibromatosis II, bilateral vestibular schwannomas, carcinomatous meningitis, intravascular lymphomatosis, others) | Abnormal brain MRI, cerebrovascular imaging study, or CSF |
| Sarcoidosis | Pulmonary symptoms, bilateral vestibular loss, elevated angiotensin converting enzyme (ACE) level, abnormal gallium scan |
| Hyperviscosity syndrome | Mucous membrane bleeding, neurologic and pulmonary symptoms, associated retinopathy |
Treatment
Table 6. General Guidelines for Corticosteroid Therapy for SSNHLa
| Systemic Corticosteroids | Intratympanic Corticosteroids | |
|---|---|---|
| Timing of Treatment | Immediate, ideally within first 14 days. Benefit has been reported up to six weeks post onset of SSNHL. | 1. Immediate 2. Salvage (rescue) after initial treatment fails or after 2 weeks from symptom onset |
| Dose | Prednisone 1 mg/kg/day (usual maximal dose is 60 mg/day) or Methylprednisolone 48 mg/day or Dexamethasone 10 mg/day | Dexamethasone 24 mg/mL (compounded), or 10 mg/mL (stock) if compounded concentration unavailable or Methylprednisolone 40 mg/mL or 30 mg/mL |
| Duration/Frequency | Full dose for seven to 14 days, then taper over similar time period. | Inject 0.4 to 0.8 mL into middle ear space up to four injections over a two-week period |
| Technique | Do not divide doses. | 1. Fill the middle ear with steroid solution 2. Keep head in otologic position (one side down, affected ear up) for 15–30 minutes |
| Monitoring | Audiogram at completion of treatment course and at delayed intervals. | Audiogram at completion of treatment course and at delayed intervals. Interval audiograms between injections may help direct early termination of therapy if hearing loss resolves. Inspect tympanic membrane to ensure healing at completion of treatment course, and at a delayed interval. |
| Modifications | Medically treat significant adverse drug reactions, such as insomnia. Monitor for hyperglycemia, hypertension in susceptible patients. | May insert pressure-equalizing tube if planning multiple injections, but this increases risk of tympanic membrane perforation. |
Table 7. Common Issues Raised by Individuals with SSNHL
| Counseling Topic | Type of Counseling | Suggestions |
|---|---|---|
| Is there anything I can do to restore my hearing? | Informational counseling | Discuss various treatment options and possible outcomes. |
| What are the risks of treatment? | Informational counseling | Benefits and risks of treatment options. |
| Will I lose hearing in my other ear? | Personal adjustment counseling | Advise that the risk of SSNHL in the other ear is very low. |
| Is there anything I can do to help my hearing now that medical therapies are done and I still have hearing loss? | Personal adjustment/informational counseling | Introduce amplification and rehabilitation options. |
| How will I be able to manage with hearing in just one ear? | Personal adjustment counseling | Discuss support groups such as Hearing Loss Association of America (HLAA). |
| Do I have to wear a hearing aid? | Personal adjustment/Informational counseling | Discuss types of hearing aids and Contralateral Routing of Signal (CROS) and Bilateral Contralateral Routing of Sound (BiCROS) option if appropriate. |
| Is there any surgery I can have to get my hearing back? | Informational/personal adjustment | Discuss surgical options (i.e. cochlear implant, osseointegrated implant) if a candidate. |
