Sudden Sensorineural Hearing Loss
Sudden sensorineural hearing loss (sudden SNHL) is considered a medically urgent
condition. About 40,000 Americans experience sudden SNHL each year. About half of
these patients recover their hearing partially or completely within two weeks. Even though
the etiology of this condition is multifactorial and often unknown, prompt initiation of
treatment, within a week of onset, has been shown to improve outcomes.
Diagnosis of sudden SNHL focuses on determining the causative factor. A full history and physical should include the following: The circumstances and time of onset should be elicited as well as any associated symptoms like vertigo, tinnitus or aural fullness. History of diving, flying or straining, autoimmune or hematologic disease, upper respiratory
illness, or otologic surgery should be included. Causes of sudden SNHL are many and
include, but the first two in the following list are by far the most common:
- Inflammation, most commonly viral, but also bacterial (meningococcal meningitis,
- Middle ear-inner ear interaction, pathology of the middle ear can affect the inner ear via the round window of the labyrinth, e.g. barotraumas
- Vascular insufficiency, particularly in the vertebrobasilar circulation, diabetics are at increased risk
- Meniere’s disease
- Autoimmune inner ear disease or a number of systemic autoimmune conditions
- Trauma, i.e. temporal bone fracture, labyrinth concussion, or a traumatic perilymph fistula
- Ototoxic medications, classically aminoglycosides
- Neurologic, multiple sclerosis
- Neoplastic, vestibular schwannoma, leukemia, myeloma and metastases to the temporal bone
A definitive diagnosis is identified in less than 10% of cases. Most cases are labeled as
idiopathic. Prompt identification of the problem is important, as treatment of idiopathic
sudden SNHL has been shown to be effective if commenced promptly. Laboratory studies
may include CBC, ESR, VDRL, lyme titer in endemic areas. MRI is ordered if a vestibular
schwannoma or multiple sclerosis is suspected. Referral to an otolaryngologist should
occur within a few days, in order to obtain an audiogram and full evaluation.
Treatment of sudden sensorineural hearing loss should be commenced as soon as possible, preferably within a few days of onset. A number of steroids, antivirals, vasodilators
and diuretics have been used for treatment of sudden SNHL. Steroids are the only
treatment currently supported by evidence. Prednisone 1 mg/kg is usually given for
2-4 weeks, followed by a taper. Hearing loss is followed with serial audiograms. If there
is no improvement, the patient may be a candidate for intratympanic steroid injections. Valacyclovir is commonly included in the treatment regimen for presumed viral cochleitis,
but the evidence for its efficacy is lacking. Surgery can be performed to reinforce the round
window and provide a better barrier between the middle and inner ear.
Prognosis for a partial or complete hearing recovery without
treatment is approximately 50%. If steroid treatment is
initiated within the first week, this recovery rate may be
higher. Prognosis is better if hearing loss is milder, if there is some recovery seen within 2 weeks, and if vertigo is absent.
Call us at 612-339-2836 or toll-free at 866-316-0769 to refer your patient for an appointment, or submit an online referral.