Sudden sensorineural hearing loss (SSNHL) is an otologic emergency
Sudden sensorineural hearing loss is defined as hearing loss of 30 or more decibels across 3 contiguous audiometric frequencies within 72 hours. The incidence is about 30 per 100 000 people annually and predominantly affects those aged 40–60 years.1 This type of hearing loss is typically unilateral and often idiopathic (90%), although it has been associated with infections, autoimmunity, and vascular diseases.1
Sudden sensorineural hearing loss can be associated with other otologic symptoms
Smoking, alcohol consumption, diabetes, and hypertension are risk factors. 1 Tinnitus, aural fullness, and vertigo can be associated with the presentation of SSNHL.2 Recent head trauma, barotrauma, or focal neurologic deficits suggest an alternative diagnosis.
A thorough otoscopic examination is required to rule out other etiologies
Otoscopic examination can rule out cerumen impaction, tympanic membrane perforation, foreign bodies, and middle ear effusions.2 Rinne and Weber tuning fork tests help differentiate between conductive versus sensorineural hearing loss (Appendix 1, available at www.cmaj.ca/lookup/doi/10.1503/cmaj.240457/tab-related-content). An audiogram should be obtained within 14 days of symptom onset but should not delay treatment.2
Corticosteroids are the first-line treatment for SSNHL
Patients can be treated with oral corticosteroids (prednisone 1 mg/kg/d, with a maximum dose of 60 mg/d for 10–14 d) and urgently referred to otolaryngology.2 Laboratory testing and computed tomography are not recommended.2 Specialist referral can facilitate further investigation with magnetic resonance imaging to rule out retrocochlear pathology. Treatment with intratympanic corticosteroid injections may be offered to patients at high risk of adverse effects from oral corticosteroids, with moderate or severe hearing loss, or to people who don’t respond to treatment, as salvage therapy.2–4
The prognosis of SSNHL is variable
About 50% of patients regain hearing to some extent.5 Older age, severe hearing loss, and vertigo are associated with worse outcomes, whereas shorter time to treatment with corticosteroids is a positive prognostic factor. 4,5 Residual hearing loss can be improved with hearing aids.2
Supplementary Information
Footnotes
Competing interests: None declared.
This article has been peer reviewed.
References
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