دانلود رایگان ترجمه مقاله کاهش شنوایی حسی عصبی ناگهانی – Sage 2011

کاهش شنوایی حسی عصبی ناگهانی: مروری بر تشخیص، درمان و پیش آگهی

Sudden Sensorineural Hearing Loss: A Review of Diagnosis, Treatment, and Prognosis

Abstract

Sudden sensorineural hearing loss (SSNHL) is commonly encountered in audiologic and otolaryngologic practice. SSNHL is most commonly defined as sensorineural hearing loss of 30dB or greater over at least three contiguous audiometric frequencies occurring within a 72-hr period. Although the differential for SSNHL is vast, for the majority of patients an etiologic factor is not identified. Treatment for SSNHL of known etiology is directed toward that agent, with poor hearing outcomes characteristic for discoverable etiologies that cause inner ear hair cell loss. Steroid therapy is the current mainstay of treatment of idiopathic SSNHL in the United States. The prognosis for hearing recovery for idiopathic SSNHL is dependent on a number of factors including the severity of hearing loss, age, presence of vertigo, and shape of the audiogram.

Introduction

Sudden sensorineural hearing loss (SSNHL) is most often defined as sensorineural hearing loss of 30dB or greater over at least three contiguous audiometric frequencies occurring over 72 hr (Wilson, Byl, & Laird, 1980). SSNHL is a relatively common complaint in otologic and audiologic practices (1.5-1.7 per 100 new patients presenting in our practice). For 7% to 45% of patients, a defined cause can be identified and specific therapeutic regiment used for treatment (Byl, 1984; Chau, Lin, Atashband, Irvine, & Westerberg, 2010; Fetterman, Saunders, & Luxford, 1996; Huy & Sauvaget, 2005; NosratiZarenoe, Arlinger, & Hultcrantz, 2007; Shaia & Sheehy, 1976). The majority of patients with sudden SNHL have no identifiable cause for hearing loss and are classified as “idiopathic” (Byl, 1984; Chau et al., 2010; Fetterman et al., 1996; Nosrati-Zarenoe et al., 2007; Shaia & Sheehy, 1976). Despite extensive research, controversy remains in the etiology and appropriate care of patients with idiopathic SSNHL Regardless of etiology, recovery of hearing thresholds following SSNHL may not occur, may be partial, or can be complete. Factors impacting hearing recovery include age at onset of hearing loss, hearing loss severity and frequencies affected, presence of vertigo, and time between onset of hearing loss and visit with the treating physician (Byl, 1984). Over 1,200 articles on SSNHL are available on PubMed, and many more articles on the subject predate the PubMed era. For practitioners, the enormous number of articles on this topic can be overwhelming, particularly as recommendations vary greatly between publications. In this article, we summarize the available literature and suggest guidelines for evaluation and management of SSNHL.

Epidemiology

The incidence of SSNHL is 5-20 per 100,000 (Byl, 1984; Fetterman et al., 1996; Hughes, Freedman, Haberkamp, & Guay, 1996). The true incidence of SSNHL may be higher than these estimates because affected individuals who recover quickly do not present for medical care (Byl, 1984; Simmons, 1973). Although individuals of all ages can be affected, the peak incidence is between the fifth and sixth decade of life. SSNHL occurs with equal incidence in men and women (Byl, 1984; Fetterman et al., 1996; Nosrati-Zarenoe et al., 2007; Shaia & Sheehy, 1976). Nearly all cases are unilateral; less than 2% of patients have bilateral involvement and typically bilateral involvement is sequential (Byl, 1984; Fetterman et al., 1996; Huy & Sauvaget, 2005). Accompanying symptoms include tinnitus (41% to 90%) and dizziness (29% to 56%) (Byl, 1984; Fetterman et al., 1996; Huy & Sauvaget, 2005; Xenellis et al., 2006). Many patients report first noting their hearing loss on awakening (Chau et al., 2010).