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 30 dB 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.

Figure 1.

Audiograms of a patient initially presenting with SSNHL ultimately found to have Meniere’s disease. Note near resolution of initial hearing loss following high-dose corticosteroid therapy. Initial audiogram following SSNHL (A); audiogram following 10-day course of 1mg/kg prednisone (B); and audiogram following onset of episodes of spinning vertigo lasting 30-60 min accompanied by left aural fullness and tinnitus. Circles represent right masked air levels; squares represent left masked air levels; right facing bracket represent right masked bone levels; squares represent left masked bone levels. SSNHL, sudden sensorineural hearing loss.

Figure 2.

MRI of patient with SSNHL. This patient’s moderate flat SSNHL resolved completely following treatment with 1mg/kg prednisone and oral antiherpetic medications for 10 days followed by a short prednisone taper. Note small left intracanalicular enhancing mass consistent with vestibular schwannoma (arrowhead). MRI, magnetic resonance image; SSNHL, sudden sensorineural hearing loss.

Figure 3.

Audiograms of two patients presenting with idiopathic SSNHL. Both patients were women in their mid-40s who presented with complaints of SSNHL within less than 1 week of onset. Both patients were treated with 1mg/kg prednisone and oral antiherpetic medications for 10 days. Initial audiogram following onset of SSNHL for Patient 1 (A); follow-up audiogram at 2 weeks (B); initial audiogram following onset of SSNHL for Patient 2 (C); follow-up audiogram at 3 weeks for Patient 2 (D). SSNHL, sudden sensorineural hearing loss.

Figure 4.

Proposed algorithm for evaluation of patients presenting with SSNHL. Many unnecessary tests can be avoided by using risk factor criteria for laboratory tests; however, in areas of high prevalence of a given infectious disease uniform testing for that agent should be considered. SSNHL, sudden sensorineural hearing loss.

Figure 5.

Pure-tone audiogram configurations associated with different hearing outcomes following idiopathic SSNHL. Upsloping (A), flat (B), downsloping (C), and profound (D) configurations are shown with corresponding hearing recovery rates. SSNHL, sudden sensorineural hearing loss.