Diagnostic yield of MRI of the brain and IAC in patients with neurotologic complaints.

OBJECTIVES: Quantify number of MRI scans obtained in a tertiary neurotology practice and identify likelihood of pathologic findings. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary neurotology center. SUBJECTS AND METHODS: A retrospective analysis of all adult patients over 20 months (3/2012-10/2013) where MRI was deemed necessary for evaluation of neurotologic complaints. Demographics, clinical history, physical examination, and audiometric findings were used to categorize new patients into 7 groups: definite Meniere's disease (MD), probable MD, possible MD, vague dizziness, tinnitus only, asymmetric hearing loss (HL), and other symptoms to stratify risk for retrocochlear tumor and other relevant pathology. RESULTS: 1537 MRI scans were performed, 932 of these were for a new diagnosis. Discovering retrocochlear tumors was rare (1.4%). Patients with HL had a 0.3% (1/314) chance of retrocochlear tumor and 3.2% (10/314) chance of relevant pathology. Patients with only unilateral tinnitus had no evidence of retrocochlear tumors, and 3.8% chance of finding relevant pathology. Patients with "definite" or "probable" MD had no evidence of retrocochlear tumor or other relevant findings. All discovered acoustic neuromas were in the "possible MD" category, which had a 9.3% chance of finding all relevant pathology. CONCLUSIONS: In a tertiary neurotology center, the likelihood of finding a retrocochlear tumor on MRI is rare. In the current study, unilateral tinnitus exclusively, "definite MD," and "probable MD" failed to yield a single example of retrocochlear tumor. Patients with "possible MD" had the highest probability of finding retrocochlear tumors and other relevant pathology.

Evoked response audiometry in scrub typhus: prospective, randomised, case-control study.

OBJECTIVE: To investigate the hypothesis of cochlear and retrocochlear damage in scrub typhus, using evoked response audiometry. STUDY DESIGN: Prospective, randomised, case-control study. METHODS: The study included 25 patients with scrub typhus and 25 controls with other febrile illnesses not known to cause hearing loss. Controls were age- and sex-matched. All subjects underwent pure tone audiometry and evoked response audiometry before commencing treatment. RESULTS: Six patients presented with hearing loss, although a total of 23 patients had evidence of symmetrical high frequency loss on pure tone audiometry. Evoked response audiometry found significant prolongation of absolute latencies of wave I, III, V, and wave I-III interpeak latency. Two cases with normal hearing had increased interpeak latencies. These findings constitute level 3b evidence. CONCLUSION: Findings were suggestive of retrocochlear pathology in two cases with normal hearing. In other patients, high frequency hearing loss may have led to altered evoked response results. Although scrub typhus appears to cause middle ear cochlear and retrocochlear damage, the presence of such damage could not be fully confirmed by evoked response audiometry.

[Sphenoidal sinus polyp-cyst as casual finding in a patient with severe and sudden retrocochlear hearing loss]. / Pólipo-quiste del seno esfenoidal como hallazgo casual en paciente con hipoacusia brusca severa retrococlear.

We present the case of a 56 years old female controlled in our ENT Department because of right sudden hearing loss, tinnitus and vertigo. The endoscopic exam was normal. Audiogram showed a severe neurosensorial hypoacusia and PEATC confirmed the so called hypoacusia suggesting a retrocochlear origin of it. As imaging tests an otic-craneal CT and IRM were asked for, which informed of the presence of a cystic lesion versus polyp in sphenoidal sinus of 15 x 10 mm without other alterations or significant pathology.

Auditory brainstem response versus magnetic resonance imaging for the evaluation of asymmetric sensorineural hearing loss.

OBJECTIVES/HYPOTHESIS: Auditory brainstem response (ABR) testing and magnetic resonance imaging (MRI) are compared for the evaluation of patients with asymmetric sensorineural hearing loss (SNHL). MRI with gadolinium administration is the current gold standard for identifying retrocochlear lesions causing asymmetric SNHL. The study seeks to determine the sensitivity and specificity of ABR in screening for possible retrocochlear pathology. Most important among SNHL etiologies are neoplastic lesions such as vestibular schwannomas, cerebellopontine angle (CPA) tumors, as well as multiple sclerosis, stroke, or other rare nonneoplastic causes. The study results will allow the author to recommend a screening algorithm for patients with asymmetric SNHL. STUDY DESIGN: The study is a multi-institutional, institutional review board approved, prospective, nonrandomized comparison of ABR and MRI for the evaluation of patients with asymmetric SNHL. METHODS: Three hundred twelve patients (between the ages of 18 and 87) with asymmetric SNHL completed the study. Asymmetric SNHL was defined as 15 dB or greater asymmetry in two or more frequencies or 15% or more asymmetry in speech discrimination scores (SDS). These patients prospectively underwent both ABR and MRI. The ABR and MRI were interpreted independently in a blinded fashion. In addition to the ABR and MRI results, a variety of clinical and demographic data were collected. RESULTS: Thirty-one (9.94%) patients of the study population of 312 were found on MRI to have lesions causing their SNHL. Of the 31 patients with causative lesions on MRI there were 24 vestibular schwannomas, 2 glomus jugulare tumors, 2 ectatic basilar arteries with brainstem compression, 1 petrous apex cholesterol granuloma, 1 case of possible demyelinating disease, and 1 parietal lobe mass. Twenty-two of the 31 patients had abnormal ABRs, whereas 9 patients (7 with small vestibular schwannomas) had normal ABRs. This gives an overall false-negative rate for ABR of 29%. The false-positive rate was found to be 76.84%. Sensitivity of ABR as a screening test was 71%, and specificity was 74%. CONCLUSIONS: Ten percent of patients with asymmetric SNHL (by this study's criteria) are likely to have causative lesions found on MRI. Although the recently reported annual incidence of vestibular schwannoma in the general population is 0.00124%, for patients with asymmetric SNHL in this study, the incidence was 7.7% (nearly 4 orders of magnitude higher). ABR has been demonstrated to have low sensitivity and specificity in the evaluation of these patients and cannot be relied on as a screening test for patients with asymmetric SNHL. Keeping the use of MRI conditional on the results of ABR will annually result in missed or delayed diagnosis of causative lesions in 29 patients per 1,000 screened. The author recommends abandoning ABR as a screening test for asymmetric SNHL and adoption of a focused MRI protocol as the screening test of choice (within certain guidelines).

[Idiopathic sudden deafness]. / Les surdités brusques idiopathiques.

PURPOSE: Sudden idiopathic deafness is a sensorineural hearing loss with no recognized causes at the time of onset. The impairment site is usually localized in the cochlea, but some cases of retrocochlear lesions (e.g., cerebellopontine angle tumors, degenerative neural diseases, neuraxial ischemic lesions) can induce sensorineural deafness. The medical management of patients presenting with sudden deafness aims at detecting a causal mechanism, and at administering emergency therapeutic drugs. The diagnosis of idiopathic sudden deafness can be definitely made when no causes are found. Usually, the impairing mechanism involves the cochlea. The pathophysiology of this sensorineural alteration is still unknown. It is most likely that several mechanisms are associated together, their common point being an impairment to the feedback loop of the organ of Corti. CURRENT KNOWLEDGE AND KEY POINTS: It is very likely that reactivation of neurotropic viruses and/or cochlear ischemia are frequent etiologies. Whatever the cause, the treatment is to be administered urgently, and consists of a high-dose corticotherapy at the least. Other treatments have never really proven to be effective. It is secondarily checked that no retrocochlear pathological processes, such as a cerebellopontine angle tumor, is present, in particular in young people. FUTURE PROSPECTS AND PROJECTS: One of the current objectives is to determine when cochlear ischemia is involved, in a mini-invasive manner, such as with laser Doppler flowmetry, so that the treatment can be optimized. From a therapeutic point of view, early acoustic protection has been proven to be effective in cases of cochlear ischemia in small laboratory animals. Its efficacy in case of sudden deafness, non-exclusive of other causes than ischemia, is being assessed in a multicentric project.