Idiopathic sudden sensorineural hearing loss: a review

Idiopathic Sudden Sensorineural Hearing Loss (ISSHL) remains one of the major unsolved otologic emergencies. It is characterized by the onset of an unilateral sensorineural hearing loss developing within 24 hours, and averaging on pure tone audiogram at least 30 dB HL for three subsequent octave steps, with no marked vestibular symptoms and no identifiable cause. ISSHL is a syndrome covering several heterogeneous entities resulting from different pathogenetic mechanisms. At this time, the audiogram is the unique tool which may help clinicians to identify these entities and provide a classification based on 5 types of hearing loss. Numerous experimental and clinical studies have investigated the mechanisms by which infectious, ischemic, mechanic or immunologic insults may induce cochlear dysfunction. However, extrapolation to humans and rationale therapeutic approaches to ISSHL remain uncertain. SSHL being a diagnosis of exclusion, retrocochlear and neurologic etiologies should be eliminated. No argument allows to consider ISSHL a therapeutic emergency. More precisely, the experimental data presently available on cochlear physiology suggests that a treatment could have some chance to be effective if undertaken within minutes following the onset of ISSHL, a condition never encountered in daily practice. Conversely, it is not justifiable to impute the absence of hearing recovery to a delay in therapy. The various therapeutic strategies currently recommended are highly empirical and should be questionned in terms of cost-effectiveness, the most common being high-dose corticosteroids. New investigation tests are required for improving our approach to ISSHL.     

Etiologic diagnosis of sensorineural hearing loss in adults

OBJECTIVE: To determine the etiology of adult-onset sensorineural hearing loss. STUDY DESIGN AND SETTING: This is a prospective cohort study of 60 adult subjects with bilateral sensorineural hearing loss of no obvious etiology by medical history and physical examination. These patients were evaluated at an academic medical center and underwent evaluation by high-resolution computed tomography of the temporal bone, autoimmune panel, and DNA testing for mutations of both the GJB2 gene and the mitochondrial DNA (1555A>G and 7445A>G). RESULTS: An etiologic diagnosis was achieved in 6 patients: cochlear otosclerosis, 1 case; dilated vestibular aqueduct, 1 case; a mitochondrial DNA 7445A>G mutation, 3 cases; and a mitochondrial DNA 1555A>G mutation, 1 case. CONCLUSION: This result underscores the importance of a search for the etiology of a hearing deficit in adult patients. There are specific interventions now available for the management of hearing-impaired patients with cochlear otosclerosis and mitochondrial DNA mutations.     

Idiopathic sudden sensorineural hearing loss in dialysis patients

Although sudden sensorineural hearing loss (SSNHL) affects chronic kidney disease (CKD) patients more frequently than non-CKD patients, few reports have described SSNHL in dialysis patients. We aimed to review the characteristics of SSNHL in chronic dialysis patients and evaluate treatment responses to steroid therapy. We retrospectively reviewed the records of dialysis patients diagnosed with idiopathic SSNHL at Asan Medical Center between January 2000 and December 2014. Pure tone and speech audiometry analyzes were performed before and 2?weeks and 2?months after treatment onset to evaluate outcomes. Twenty-two patients (11 men, 11 women; mean age: 49.9?±?11.7?years) were included; 16 (72%) and 6 (28%) had undergone hemodialysis and peritoneal dialysis, respectively, for a median of 49.2?±?41.4 (1–144) months. End-stage renal disease was most frequently caused by diabetic nephropathy (11 cases), chronic glomerulonephritis (1 case) and unknown factors (7 cases). Common accompanying symptoms included tinnitus (68.2%), ear fullness (45.5%) and vertigo (27.3%). The mean pure tone audiometry threshold at the initial presentation was 82.6?±?22.4?dB. At 2?months post-steroid treatment, 4 (18.2%), 4 (18.2%) and 6 (27.3%) patients exhibited a complete, partial, or slight recovery, respectively; 8 patients (36.3%) showed no improvement. Although we could not identify the specific cause of SSNHL in this population, our relatively large case series elucidates the precise clinical features of SSNHL in this population and demonstrates the outcomes of steroid treatment.     

Asymmetric sensorineural hearing loss in a community-based population

Asymmetric sensorineural hearing loss (ASNHL) is fairly common, but it can be an indication of retrocochlear pathology. The incidence of acoustic neuroma (AN) has been estimated at 1/100,000; however, the incidence of AN in patients with ASNHL is unknown. The limitation of health care resources challenges otolaryngologists to develop reasonable cost-containment guidelines for the evaluation of patients with ASNHL for the presence of retrocochlear pathology. A 5-year (1990 to 1994) retrospective study of all patients with ASNHL who were evaluated in a community-based general otolaryngology practice was performed. Demographic, historic, and audiologic data and results from ABRs and radiologic studies were summarized. ASNHL was present in 325 patients. Auditory brain stem response tests were performed in 179 patients (55%), and 92% (164 of 179) were normal. Patients with abnormal or inconclusive auditory brain stem responses and patients with severe SNHL were evaluated with radiologic studies (46 patients). Among the 193 patients who had diagnostic studies, 4 were found to have ANs, for a prevalence of 2.1%. The charge of diagnosis per AN was more than $41,000. In summary, a small percentage of patients with ASNHL have retrocochlear pathology, and the charge of diagnosis per AN can be excessive. A cost-containment approach for the evaluation and management of patients with ASNHL is proposed.     

Vestibular schwannoma in patients with sudden sensorineural hearing loss

Sudden sensorineural hearing loss (SSNHL) has several etiologies. It may be a presenting symptom of vestibular schwannoma (VS). This study aimed to establish the incidence of VS in patients with SSNHL, and we report several unusual cases among these patients. We reviewed retrospectively the charts and magnetic resonance imaging (MRI) findings of all adult patients who presented with SSNHL between 2002 and 2008. We utilized three-dimensional fast imaging with steady-state acquisition temporal MRI as a screening method. Of the 295 patients with SSNHL, VS was found in 12 (4%). All patients had intrameatal or small to medium-sized tumors. There were three cases with SSNHL in one ear and an incidental finding of intracanalicular VS in the contralateral ear. There were four cases of VS that showed good recovery from SSNHL with corticosteroid treatment. There were two cases that mimicked labyrinthitis with hearing loss and vertigo. A greater number of cases than expected of VS were detected in patients with SSNHL, as a result of increasing widespread use of MRI. Various unusual findings in these patients were identified. MRI would seem to be mandatory in all cases of SSNHL.     

Efficacy of serologic testing in asymmetric sensorineural hearing loss.

PURPOSE: The goal of this study was to determine the efficacy of a detailed questionnaire, auditory brain stem response testing (ABR), MRI, and an extensive battery of serologic tests in diagnosing asymmetric sensorineural hearing loss (ASNHL). METHODS AND MATERIAL: Patients with audiograms demonstrating ASNHL of 10 dB or greater in 2 consecutive frequencies or 15 dB in any 1 frequency between 250 and 6000 Hz were asked to participate. Patients underwent MRI scanning of the cerebellopontine angle, internal auditory canals, and posterior fossa with gadolinium contrast, ABR, and an extensive battery of tests. The causative diagnosis was made by the individual clinician based on each patient's history, physical examination, and test results. RESULTS: Forty-five patients completed the study. A review of the data confirmed the utility of a detailed history and physical examination, MRI, and fluorescent treponemal antibody test in all cases. Erythrocyte sedimentation rate, glycosylated hemoglobin, Lyme antibody titers, and total hemolytic component (CH50) were helpful in selected cases. Thyroid function testing, complete blood count, Sequential Multiple Analysis-7, prothrombin time/partial thromboplastin time, lipid profile, and ABR were of no value in these patients. CONCLUSION: A careful history and physical examination, MRI, and fluorescent treponemal antibody test should be performed for the evaluation of all patients with ASNHL; however, more extensive serologic testing, including sedimentation rate, glycosylated hemoglobin, Lyme antibody titers, and CH50, should be selectively performed, based on a suggestive history or suspicious physical findings.     

Hearing outcome of sudden sensorineural hearing loss: long-term follow-up.

OBJECTIVE: To evaluate the time-dependent progress and delayed improvement in patients who were treated with combination therapy including oral corticosteroid for idiopathic sudden sensorineural hearing loss. STUDY DESIGN AND SETTING: This retrospective study at a secondary referral and university-based center included 156 patients who were treated by 10-day course of admission therapy and followed for at least three months. RESULTS: Of 121 patients who recovered over three months of follow-up, 45.5% showed a delayed recovery after the end of 10-day course of therapy. Of these 55 patients, 78.2% recovered within one month, 5.5% recovered within one to two months, 12.7% recovered in two to three months, and 3.6% recovered later than three months after discharge. CONCLUSIONS: This study describes the long-term results for a three-month retrospective series of 156 patients diagnosed with idiopathic sudden sensorineural hearing loss, although this result should be further studied by additional research.     

The use of diagnostic testing in asymmetric sensorineural hearing loss

The etiology of an asymmetric sensorineural hearing loss can often be difficult to determine. Because a wide variety of pathologic processes may be responsible for the hearing loss, numerous diagnostic tests are usually used in the initial evaluation, including pure-tone audiometry, acoustic reflex testing, imaging, serologic testing, and auditory brainstem response testing. The diagnostic evaluations of 225 consecutive cases of asymmetric sensorineural hearing loss are reviewed. A cochlear site-of-lesion was demonstrated in the majority (194) of patients. Because all retrocochlear lesions (31) were associated with an abnormal auditory brainstem response, imaging should be performed in that group of patients. Magnetic resonance imaging offers greater specificity than computed tomography. Reflex decay, acoustic reflex testing, and rollover were all associated with a high false-negative rate. Whereas serologic testing for syphilis yielded several cases of otosyphilis, thyroid function testing was of little value. A diagnostic protocol for asymmetric sensorineural hearing loss is presented.     

Idiopathic sudden sensorineural hearing loss in patients undergoing long-term haemodialysis

Idiopathic sudden sensorineural hearing loss (ISHL) has been recently recognized and is increasing in frequency in patients undergoing long-term haemodialysis. Although this is one of the annoying complications impairing quality of life in haemodialysis patients, there has been little clinical evidence about ISHL in haemodialysis patients until now. We have examined retrospectively the clinical features of 6 ISHL patients, 3 males and 3 females, with a mean age of 54 years, who underwent regular haemodialysis with a mean haemodialysis duration of 90 months from 1985 to 1989. Although a specific cause for ISHL could not be identified in this study, more precise clinical features of ISHL in patients undergoing haemodialysis have been elucidated. ISHL seemed to develop more frequently in haemodialysis patients and occurred in patients undergoing haemodialysis for a relatively long time, being independent of the high-frequency-deficit type hearing disturbances usually observed in the early course of haemodialysis therapy. Above all, diabetic haemodialysis patients were more susceptible to ISHL, occurring in 4 cases out of 6. Its prognosis was not necessarily bad, showing a recovery rate of 83%, but more effective therapy should be explored for improving the quality of life in haemodialysis patients.     

Investigations into the cause of vertigo in sudden sensorineural hearing loss

In this light microscopic study of the temporal bone, an attempt has been made to find a morphologic correlate of vertigo associated with idiopathic sudden sensori-neural hearing loss (ISSHL). Hair cell densities of the three cristae and both maculae, as well as vestibular ganglion cell (neuronal) count estimation, was done in nine ears that had documented histories of ISSHL. There were five ears with vertigo and four without. These quantitative data--i.e., hair cell densities and neuronal counts, of the vertiginous ears (group I) and nonvertiginous ears (group II)--was compared by histograms and statistically. Additionally, in each of the two groups, the data from three opposite normal hearing ears were taken as a control and used for comparison with the ISSHL ears. The differences between the vertiginous, nonvertiginous, and control ears were not significant at the 0.01 level, indicating that the vertigo was not caused by hair cell or neuronal degeneration. Gross morphologic alterations in the vestibular system, such as membrane ruptures, endolymphatic hydrops, etc., were also assessed, but no clear-cut pathology was identified in the vertiginous and nonvertiginous ears. The absence of a light microscopic morphologic correlate for vestibular disturbances associated with ISSHL suggests that the symptoms could result from ultrastructural changes in the hair cells and their synapses or from biochemical alterations in their environment.     

Acyclovir in the treatment of idiopathic sudden sensorineural hearing loss.

BACKGROUND: Idiopathic sudden sensorineural hearing loss (ISSNHL) is a vexing problem that continues to pose a diagnostic and therapeutic enigma for the otologist. The aim of the study, adopting the viral theory, was to discover whether patients with ISSNHL would benefit from early treatment with acyclovir and hydrocortisone compared with patients treated by hydrocortisone alone. METHODS: Sixty patients with ISSNHL were treated in a prospective controlled randomized manner. Patients were seen within 7 days of onset and were divided randomly into 2 groups. The study group patients were treated with acyclovir and hydrocortisone, whereas those in the control group were treated with hydrocortisone alone. RESULTS: We compared the 2 groups before and after treatment regarding SRT, mean hearing level at each frequency, speech reception threshold improvement, gender, age, tinnitus, and balance complaints. The overall improvement was 78%. CONCLUSION: We conclude that there probably is no benefit from the addition of acyclovir in the treatment of ISSNHL.     

Intratympanic steroid treatment in idiopathic sudden sensorineural hearing loss: A control study

BACKGROUND AND OBJECTIVE: Although systemic steroids in sudden sensorineural hearing loss (SSHL) appears to be the most effective and the most widely accepted treatment today, a significant number of patients do not respond to steroid treatment or they cannot receive steroids for medical reasons. Intratympanic (IT) administration of steroids appears to be an alternative or additional method of management without the side effects of intravenous steroids. The aim of this study is to investigate the effectiveness and safeness of IT administration of steroids in patients who had not responded to IV treatment and to compare treatment efficacy with controls. STUDY DESIGN AND SETTING: Our study consisted of 37 patients with SSHL who, at the end of 10 days of therapy with intravenous steroids as a 1st line treatment, had pure-tone 4-frequency (0.5, 1, 2, and 4 kHz) average (PTA) of worse than 30 dB or worse than 10 dB from the contralateral ear (defined as failed intravenous treatment). They were randomized into 2 groups, treatment and control. The 19 patients of the treatment group received approximately 0.5 mL sterile aqueous suspension of methylprednisolone acetate in a concentration of 80 mg/2 mL by direct injection. The procedure was carried out 4 times within a 15-day period. An audiogram was performed before each injection and approximately 1.5 months after the last session. RESULTS: All patients tolerated the procedure well. No perforation or infection was noticed in any of the patients at their last visit. With regard to the 19 patients who received intratympanic treatment, in 9 patients, the PTA threshold improved more than 10 db, in 10 patients there was no change greater than 10 db, and no patients deteriorated more than 10 db. In the control group, none of the patients showed any change greater than 10 db. The difference was statistically significant (P = 0.002). The treatment group showed an improvement in mean PTA of 14.9 dB, whereas the control group showed a deterioration of 0.8 dB, and this difference also was statistically significant (P = 0.0005). IT treatment (P = 0.0001), better post-IV PTA (P = 0.0008), and absence of vertigo (P = 0.02) were good predictors of the outcome. In contrast, sex, age, affected ear, days to admission, and pattern of the initial audiogram showed no significant influence on the outcome. CONCLUSION AND SIGNIFICANCE: IT steroid administration after failed intravenous steroids is a safe and effective treatment in sudden sensorineural hearing loss.     

Evaluation of super-high-dose steroid therapy for sudden sensorineural hearing loss.

OBJECTIVE: To determine the efficacy of a high-dose steroid regimen for patients with sudden sensorineural hearing loss (SSNHL) and to evaluate the relationship between outcome and initial steroid dose. STUDY DESIGN AND SETTING: We conducted a retrospective study of 112 patients presenting to Saitama Medical Center. Patients received tapering courses of hydrocortisone (HC) with an initial dose of either 1200 mg or 600 mg. RESULTS: More than 87% of patients had recovery of hearing. When hearing stabilized, there were no significant differences between the 1200 mg and 600 mg groups in terms of hearing outcome (P>0.05). However, at completion of treatment, the 1200 mg group exhibited significantly superior complete recovery rate and improvement rate (P<0.05). CONCLUSION: Application of our treatment protocol of a tapered course of 1200 mg HC significantly and rapidly improves recovery outcomes in patients of SSNHL. EBM rating: C-4.     

Diagnosis and treatment of sudden-onset sensorineural hearing loss: a study of 51 patients.

OBJECTIVE: The study purpose was to determine the efficacy of steroid and antiviral therapy in the management of idiopathic sudden sensorineural hearing loss (SSNHL). STUDY DESIGN AND SETTING: We conducted a retrospective study of patients presenting to an academic tertiary care center. Fifty-one patients were evaluated. All patients were placed on the same treatment protocol. RESULTS: Thirty-seven patients (73%) had recovery of hearing. Ninety-one percent of patients with vertigo and all patients with mid-frequency hearing loss and up-sloping hearing loss recovered with treatment (P < 0.05). Recovery was significantly related to age, onset of hearing loss, and audiogram type; however outcome was not significantly related to gender, vertigo, tinnitus, or laterality (P < 0.05). CONCLUSION: Our treatment protocol produced a recovery rate, which exceeds the spontaneous recovery rate. Unlike prior studies, all patients with up-sloping and mid-frequency SSNHL had recovery. In addition, vertigo did not indicate a poor prognosis. SIGNIFICANCE: Antiviral therapy and increased length of steroid treatment may play a role in the improved recovery rates.