Nejm 2008;359:833; 1993;329:1092

Cause:

• Cochlear types include presbycusis in old age, high-frequency losses worst; Ménière's disease, unilateral in 85%; ototoxic drugs, eg, streptomycin, gentamicin, which can be unilateral; maybe prevent gentamicin hearing loss with resveratrol, a naturally-occurring polyphenol (ENT 2008;87:570) and exposure to loud noise, eg, rock and roll (Nejm 1970;282:467); autoimmune inner ear disease (Jama 2003;290:1875; 1994;272:611) w sudden (days) unilateral or bilateral loss due to anticochlear antibodies
• Neural (retrocochlear), often unilateral; include most commonly viral, like measles, mumps, and adenovirus infections; neuroma, vascular occlusion, hypercoagulopathy, meningitis, syphilis, multiple sclerosis, collagen vascular diseases, trauma (often with vertigo) (Nejm 1982;306:1029), and cerebellar-pontine angle tumors as well as acute idiopathic type in middle-aged pts
• Congenital genetic syndromes; syndromic-like maternally inherited diabetes and deafness (Ann IM 2001;134:721); and non-syndromic, 50% of which are autosomal recessive mutations of one of 28 genes (Nejm 2002;346:243)

Prevalence incr by smoking (Jama 1998;279:1715)

Si + Sx:Diminished discrimination, “hum” and Weber tests go to unaffected side, positive Rinné, no recruitment (except in Ménière’s and presbycusis); if loss >40 db at 2000 cps in best ear in elderly, it causes significant dysfunction and is markedly improved by hearing aid (Ann IM 1990;113:188). Vertigo with Ménière’s, trauma, and acute idiopathic type