Sudden Hearing Loss

Sudden Hearing Loss

Enrique Perez

Laura J Bontempo


The rapid onset of unilateral or bilateral hearing loss can be a devastating event. Beyond the immediate sensory disorientation, which can lead to difficulty with sound localization and the ability to understand speech, particularly in noisy environments, persistence of hearing loss can significantly impact quality of life. This impact is even more pronounced in patients who experience hearing loss along with other common coexisting symptoms such as vertigo and tinnitus.1

Sudden hearing loss is a subjective complaint of rapid-onset unilateral or bilateral hearing impairment. It is characterized as sensorineural, conductive, or mixed types, depending on the underlying mechanism. Acute-onset sensorineural hearing loss (SNHL) can be further classified as sudden sensorineural hearing loss if the onset is rapid and the magnitude is severe. Sudden SNHL is defined as hearing loss of 30 decibels or greater across at least three consecutive frequencies within 72 hours.2

Approximately 15 000 to 60 000 annual visits for sudden hearing loss present to the emergency department (ED), urgent care, or primary care facilities annually.2 Alexander et al. found the annual incidence of sudden SNHL in the United States to be 5 to 27 per 100 000 people, increasing with advancing age.3 This figure may underrepresent the incidence of sudden hearing loss because patients may not seek care if they experience spontaneous hearing recovery.



Historical features that will help a clinician narrow the differential diagnosis of a patient with sudden hearing loss include unilaterality or bilaterality, symptom recurrence, associated trauma, and the presence or absence of associated symptoms.

Clinicians can make a fairly accurate determination on whether a patient is likely experiencing SNHL or CHL based on history alone. Whether sudden or not, CHL is more often associated with a history of penetrating or nonpenetrating trauma, or infectious symptoms such as ear drainage and otalgia. The patient may also report a history of recurring infections or prior otologic procedures. On the contrary, SNHL is more often associated with other inner ear-like symptoms such as vertigo, tinnitus, or aural fullness.

Vertigo complaints are present in 30% to 60% of cases of sudden SNHL.5,6,7 This may also indicate a poor hearing prognosis and is often associated with worse degrees of hearing loss.6 New-onset tinnitus is present in almost every case of sudden SNHL, and while having little bearing on the prognosis, it can lead to functional and psychological distress.8 Importantly, when evaluating patients with acute hearing loss, it is critical to remember that erroneously labeling a case of sudden SNHL as sudden CHL can lead to delays in treatment and potentially worse hearing outcomes.

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Apr 18, 2023 | Posted by in OTOLARYNGOLOGY | Comments Off on Sudden Hearing Loss

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