Viral Causes of Sudden inner Ear Deafness

A Review of Hearing Loss Associated with Zika, Ebola, and Lassa Fever

The neglected tropical diseases Zika, Ebola, and Lassa fever (LF) have all been noted to cause some degree of hearing loss (HL). Hearing loss is a chronic disability that can lead to a variety of detrimental effects, including speech and language delays in children, decreased economic productivity in adults, and accelerated cognitive decline in older adults. The objective of this review is to summarize what is known regarding HL secondary to these viruses. Literature for this review was gathered using the PubMed database. Articles were excluded if there were no data of the respective viruses, postinfectious complications, or conditions related to survivorship. A total of 50 articles were included in this review. Fourteen articles discussing Zika virus and subsequent complications were included. Across these studies, 56 (21.2%) of 264 Zika-infected individuals were found to have HL. Twenty-one articles discussing Ebola virus and subsequent complications were included, with 190 (5.7%) of 3,350 Ebola survivors found to have HL. Fifteen additional articles discussing LF and subsequent complications were included. Of 926 individuals with LF, 79 (8.5%) were found to have HL. These results demonstrate a relationship between HL and infection. The true prevalence is likely underestimated, however, because of lack of standardization of reporting and measurement. Future studies of viral sequelae would benefit from including audiometric evaluation. This information is critical to understanding pathophysiology, preventing future cases of this disability, and improving quality of life after survival of infection.

Improvement in word recognition following treatment failure for sudden sensorineural hearing loss

Objectives

Patients with sudden sensorineural hearing loss (SSNHL) may have word recognition scores (WRS) that correlate with pure tone average (PTA). We hypothesize that there is a subset of patients with SSNHL who have improved WRS despite stable PTA.

Methods

Retrospective case review at a tertiary otolaryngology practice.

Results

We identified 13 of 113 patients with SSNHL whose WRS increased despite overall stable pure tone averages. There was an observed average improvement in WRS by 23.8 points in this patient cohort at follow-up, with mean initial PTA in the affected ear at 48.7 dB.

Conclusions

We identify a novel cohort of SSNHL patients that have failed treatment as measured by PTA, but who have increased WRS over time. These data have implications for patient counseling and lend insight into the pathophysiology of SSNHL.

IL4 receptor polymorphism is associated with increased risk of sudden deafness in Korean population

The interleukin 4 receptor (IL4R) polymorphism Q576R (rs 180275) has been well known to be associated with atopy and other inflammatory diseases. A single nucleotide polymorphism (SNP) A > G transition potentiates the binding specificity of the adjacent tyrosine residue. In this study we investigated the possible relationship between sudden deafness (SD) and IL4R polymorphism Q576R in 97 Korean SD patients and 613 controls using pyrosequencing method. The odds ratio (OR) for SD associated with the G vs. A allele was 2.58 [P < 0.0001, 95% confidence interval (CI) = 1.84-3.60]. We then sub-grouped SD into Tinnitus positive (+) and Tinnitus negative (-). G allele in Tinnitus (+) is significantly associated with the development of Tinnitus (+) [X(2) = 32.02, P < 0.0001, OR (95% CI) = 2.74 (1.91-3.93)] but not with Tinnitus (-). Taken together these results suggest that G allele could be a risk factor for SD.

Surdités brusques idiopathiques

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.

Intratympanic steroids for sensorineural hearing loss

Corticosteroids are standard treatment for a number of inflammatory and immune-mediated inner ear diseases. In recent years there has been growing interest in intratympanic administration of steroids as a means of achieving high inner ear drug concentration and low risk of systemic side effects. Idiopathic sudden sensorineural hearing loss seems to be the condition with the greatest potential for both study and clinical use of intratympanic steroid treatment. Despite promising preliminary observations, there re-main many unanswered questions about this treatment modality.

Transtympanic perfusion: indications and limitations

PURPOSE OF REVIEW

To review the most recent literature regarding the application of transtympanic inner ear perfusion in the treatment of inner ear disorders including Meniere disease, sudden sensorineural hearing loss, and autoimmune inner ear disease.

RECENT FINDINGS

The use of gentamicin perfusion in the management of Meniere disease with intractable vertigo has been demonstrated to have a very high rate of success, and is much less invasive than alternative surgical procedures such as vestibular nerve section or labyrinthectomy. The technique for achieving the highest rate of success while still minimizing the risk of cochleotoxicity continues to be investigated. Sustained delivery techniques such as the Silverstein MicroWick appear to achieve the best pharmacokinetic profile within the inner ear fluids. The end point of treatment does not necessarily require complete vestibular ablation to cure the patient, and shorter courses of treatment may help to reduce the risk of hearing loss. Cochlear Meniere disease can be treated with dexamethasone 4 mg/cc perfusion of the inner ear, which may improve the hearing, tinnitus, and pressure in the ear. Sudden sensorineural hearing loss has been managed with transtympanic steroid delivery, and this appears to be beneficial for some patients who have failed to respond to oral steroids, or have medical contraindications to systemic steroids.

SUMMARY

Inner ear perfusion via transtympanic delivery is an emerging technique in the management of inner ear disease. Improved results are expected over time as research in this area answers questions about dosage and delivery techniques, as well as identifying new applications and pharmaceuticals.

Oral steroid treatment of sudden sensorineural hearing loss: a ten year retrospective analysis

OBJECTIVE

To describe ten years of experience with Sudden Sensorineural Hearing Loss and compare the outcomes with and without treatment with oral corticosteroids.

STUDY DESIGN

Retrospective review of medical records.

SETTING

Large specialty hospital, Department of Otolaryngology.

PATIENTS

Patients presenting with sudden onset (72 hours) unilateral sensorineural hearing loss, with no evidence of Ménière's Disease, acoustic injury, retrocochlear disease, and other specifiable disorders.

INTERVENTIONS

The majority of patients received a standard course of oral corticosteroids (Prednisone 60 mg and taper). A smaller group declined treatment.

MAIN OUTCOME MEASURES

Recovery of hearing sensitivity was measured using standard audiometry and reported as change in Pure Tone Average. Word recognition scores were also analyzed.

RESULTS

When severe-to-profound cases are analyzed, a significant improvement (p <.01) in Pure Tone Average is seen in cases treated with steroids versus those untreated. When milder cases are included, a statistical floor effect prevents differentiation of these groups. Word recognition scores were significantly improved (p <.05) in the treated group.

CONCLUSIONS

Application of steroid medication significantly improves the recovery outcomes in cases of Severe Sudden Sensorineural Hearing Loss.

Sudden deafness: long-term follow-up and recurrence

We examined the long-term outcome for patients with idiopathic sudden sensorineural hearing loss (sudden deafness), including the incidence of recurrence of sudden deafness. The subjects were 1,798 individuals who came to Nagoya University hospital within 2 weeks of the onset of unilateral sudden deafness. Only 14 of the patients had a history of being diagnosed with sudden deafness. After their visit to our hospital, one patient had a recurrence in the ipsilateral ear and four patients experienced sudden deafness in the contralateral ear. We performed hearing examinations on 88 patients who revisited our hospital more than 10 years after unilateral sudden deafness. Of these patients, there was one with a recurrence in the ipsilateral ear and one with sudden deafness in the contralateral ear. Thus, in this series the recurrence of sudden deafness was rare.

[Cochlear hemorrhage. Unusual cause of sudden sensorineural deafness]

Sudden sensorineural hearing loss (SNHL) caused by intralabyrinthine hemorrhage is a rare entity usually associated to patients with previous pathological factors, such as blood dyscrasias, anticoagulant therapy and local hemorrhagic pathologies. We report the first-published case of sudden-onset deafness due to cochlear hemorrhage in a patient with no previous pathologies. We describe the history, diagnosis and follow-up of this patient in comparison to others previously published.

Role of viral and Mycoplasma pneumoniae infection in idiopathic sudden sensorineural hearing loss

Sudden deafness constitutes a challenge in terms of the etiopathogenic diagnosis. The causative origin of sudden deafness usually remains unknown. However, available evidence suggests that viral and Mycoplasma pneumoniae infection could be one factor involved. In order to analyze the incidence of these infectious agents, a microbiology study was carried out during the acute phase of the disease, and during convalescence, in 24 patients (17 men and 7 women; mean age 39.7 years; range 17-63 years) with idiopathic sudden hearing loss (SHL) according to previously published criteria. In the acute phase most of the patients presented IgG antibodies to Epstein-Barr virus (n = 23), herpes simplex virus (n = 24), parainfluenza virus (n = 24), varicella-zoster virus (n = 24) and cytomegalovirus (n = 20). Results obtained from 3 patients suggested the existence of a recent infectious process caused by Mycoplasma pneumoniae (IgM+) in 1 patient, Mycoplasma (IgM+) and influenza A virus (complement fixation titer > 1/64) in another and parainfluenza virus seroconversion (a fourfold higher titer between the acute phase and convalescence) in the third. In conclusion, the low incidence of documented positive serological tests in our series (12.5%) may be due to the presence of pathological situations other than acute infection and does not justify routine serological studies in patients with SHL.

Audiometric comparison of Lassa fever hearing loss and idiopathic sudden hearing loss: evidence for viral cause

A recently published prospective study on acute sensorineural deafness in Lassa fever among a West African population showed the audiometric pattern of a known virally induced hearing loss. Using the audiometric data from the patients with Lassa fever in that study, we analyzed and classified the initial hearing loss and final recovery into three groups by pure-tone average values and then did the same for 222 patients with idiopathic sudden hearing loss (SHL) in our study. Statistical analyses of the severity of initial hearing loss and the hearing recovery pattern indicate that the clinical course of our 222 patients with idiopathic SHL showed no statistically significant differences from the clinical course of the patients with Lassa fever. We found a marked difference in age, however, and a clinically significant difference in the incidence of bilateral hearing loss. In reviewing the literature on sudden sensorineural hearing loss, we found no apparent relation between severity of viral illness and initial hearing loss or subsequent recovery. Cummins et al. suggest that virally induced hearing loss in Lassa fever is linked to the host's immune response and not to the viremia. We thus propose a virally induced immune response mechanism for idiopathic sensorineural SHL. Further prospective studies are needed for verification.

Acute bilateral total deafness complicating mumps

While it is well known that mumps is a potential cause of deafness, it is not generally appreciated that it can produce total deafness. The damage is usually unilateral but bilateral disease has been recorded. A case is presented of severe bilateral hearing loss during a mumps epidemic in which, in spite of intensive conventional as well as lesser known therapy, no improvement occurred. In the absence of a successful therapeutic regime it is clearly advisable to intensify immunization in non-developed countries.

Sudden deafness due to infection by Mycoplasma pneumoniae

A case is described of sudden unilateral deafness associated with Mycoplasma pneumoniae. The hearing function of the patient returned to normal on the third day of treatment with tetracycline. M pneumoniae is a common causative agent of protean respiratory disease and the true incidence of hearing loss in these cases may be higher than reflected by the occasional reports. Therefore, appropriate laboratory studies should be included in the evaluation of sensorineural loss associated with diverse infections of the respiratory tract. Prompt diagnosis facilitates the administration of specific treatment. However, the actual contribution of tetracyclines to restoration of hearing cannot be assessed.