Causes of Sensorineural Hearing Loss (SNHL)
Approximately 1% of cases of sudden SNHL are due to retrocochlear disorders that may be related to vestibular schwannoma, demyelinating disease, or stroke. Another 10 to 15% are due to another identifiable cause such as Meniere's disease, trauma, autoimmune disease, syphilis, Lyme disease, or perilymphatic fistula. The remainder are idiopathic and almost exclusively unilateral.
Rare cases of bilateral sudden deafness most often reflect a psychiatric (functional) cause or a neurologic process (e.g., neoplastic dural infiltration of the posterior cranial fossa, paraneoplastic syndrome, or encephalitis).
Steroids to Treat Hearing Loss
Oral corticosteroids are routinely used for primary treatment of sudden sensorineural hearing loss, once primary causes are ruled out, although data are limited to support their use; there are also limited data to support the use of intratympanic corticosteroids for primary therapy or for treatment of those whose hearing did not improve with initial therapy. A clinical trail sponsored by the National Institutes of Health that compares oral with intratympanic corticosteroid treatment for primary therapy is under way.
New England Journal of Medicine - Vol. 359, No. 8, August 21, 2008