Menière's disease and disorders of the carbohydrate metabolism involving the inner ear

Introduction: Menière's disease was described in 1861, but there are still uncertainties regarding its pathophysiology and treatment. Endolymphatic hydrops is recognized as a fundamental pathological characteristic of the disease, as a result of an inadequate absorption of the endolymph. A milder type of endolymphatic hydrops results from an altered chemical composition of the endolymph, due to disorders of the carbohydrate metabolism. Objective: To describe the association of both types of hydrops in patients with Menière disease. Methods: This was a retrospective study of 98 patients with Menière's disease, 62 of whom also presented disorders of the carbohydrate metabolism, and 5 patients with delayed endolymphatic hydrops, 2 of whom also presented disorders of the carbohydrate metabolism. Results: The follow-up of these patients showed that the correction of the metabolic disorders may help in the clinical treatment of Menière's disease and of delayed endolymphatic hydrops, but this does not happen in the more severe types of the diseases. Conclusion: Patients with Menière's disease may present simultaneous disorders of the carbohydratemetabolism, affecting the inner ear. The correction of these disorders helps the clinical treatment but does not preclude the progression of the more severe cases of Menière disease (AU)

Suspensory Tethers and Critical Point Membrane Displacement in Endolymphatic Hydrops

Abstract Introduction Grossly displaced membranes are characteristic of endolymphatic hydrops. The process whereby physiological membrane displacement becomes pathological may be mediated by stress, but the membrane biomechanics underlying this transition are unclear. Objective This study seeks to determine the role of suspensory tethers during pressure-induced membrane displacement in the generation of the membranous lesions seen in this disease entity using a biomechanical model approach. Methods The location of membrane suspensory tethers was identified histologically. The influence of tethers on model membrane configuration during displacement was assessed graphically. The relationship of membrane configuration during displacement to curvature radius was quantified trigonometrically. The relationship of curvature radius to stress susceptibility was determined mathematically. The net effect of suspensory tethers on membrane stress levels for various degrees of membrane distention and displacement was then calculated numerically. Results In the inferior labyrinth, suspensory tethers are found to occur on the membranes' boundaries. Such tethering is found to impose a biphasic effect on membrane curvature with increasing degrees of displacement. As a consequence, tensile stress susceptibility is found to decline with initial membrane displacement to a critical point nadir beyond which stress then increases monotonically. No such effect was found for the superior labyrinth. Conclusion Boundary tethers in the inferior labyrinth are associated with significant tensile stress reductions until a critical point of membrane displacement is reached. Displacements short of the critical pointmay be physiological and even reversible,whereas such displacements beyond the critical point are apt to be overtly hydropic and irreversible.

La pérdida súbita de la audición, ¿está asociada con un mayor riesgo de aterosclerosis? / 1 IS SUDDEN HEARING LOSS ASSOCIATED WITH INCREASED RISK OF ATHEROSCLEROSIS?

Objective: sudden sensorineural hearing-loss (SSNHL) patients constitute approximately 2­3% of referrals to ear, nose and throat (ENT) clinics. Several predisposing factors have been proposed for this condition; one of which is vascular disorders and perfusion compromise. In this research the atherosclerotic changes and their known risk factors are studied in SSNHL patients. Study Design: This was a case-control study. Methods: Thirty SSNHL patients and 30 controls were evaluated with regard to cardiovascular risks including history, heart examination, blood pressure, body mass index, waist circumference, electrocardiogram, blood sugar, triglycerides, cholesterol, high-sensitivity C-reactive protein (HSCRP); also, carotid artery color Doppler study was undertaken to measure intima media thickness (IMT). Results: IMT and HSCRP showed an increased risk in the case group compared with the controls (P=0.005 and P=0.001). However, waist circumference, history of smoking, fasting blood sugar, lipid profile, and electrocardiogram revealed no significant difference between the two groups. Interestingly, blood pressure and body mass index were higher in the controls in this study. Conclusion: Sudden sensorineural hearing loss may be associated with subclinical atherosclerosis, suggesting cardiovascular check-up in selected cases if associated with other risk factors.

Utilidad de ePEAT en determinar candidatura para implante coclear en pacientes pediátricos con malformaciones de oído interno: comunicación preliminar / Use of ePEAT to determine candidacy for cochlear implant in pediatric patients with inner ear malformations: preliminary communication

En candidatos a implante coclear con malformaciones del oído interno donde se encuentra un nervio coclear anormal, los estudios tradicionales y las imágenes muchas veces no pueden dar respuesta definitiva acerca de la funcionalidad y presencia del nervio coclear. Para esto ayudarían los estudios de electrofisiología. Se presentan tres casos clínicos de pacientes con malformaciones del oído interno que fueron evaluados con ePEAT para ayudar a determinar su candidatura a implante coclear. Los estudios electrofisiológicos no reemplazan a los estudios tradicionales de evaluación auditiva ni a los estudios por imágenes, sino que los complementan. Los casos presentados, demuestran que en casos de malformaciones de oído interno o CAI muy estrecho, en que se cuestiona seriamente la existencia de un nervio coclear funcional, y en casos de neuropatía auditiva, se hace necesario evaluar la función de la cóclea separadamente de la del nervio auditivo y la función del tronco. Para esto se utilizamos los ePEAT. Los ePEAT entregan información valiosísima ya que nos permite conocer las reales capacidades de los pacientes para transmitir un estímulo auditivo hacia el sistema nervioso central, definiendo mejor las expectativas con el uso implante, asistiéndonos en nuestra toma de decisiones.

In cochlear implant candidates with inner ear malformations, where there is an abnormal cochlear nerve, traditional studies and images cannot often provide definitive answers about the functionality and presence of the cochlear nerve. In these cases, electrophysiology studies can be used. We present 3 cases of patients with inner ear malformations who were evaluated with ePEAT to determine their candidacy for a cochlear implant. Electrophysiological studies do not replace traditional hearing screening studies or imaging studies, but complement them. The cases presented in this study demonstrate that in patients with inner ear malformations or very narrow internal auditory canal, where we question the existence of a functional cochlear nerve, and in cases of auditory neuropathy, it is necessary to evaluate the cochlear function separately from the auditory nerve and from the brainstem. In these cases we use ePEAT. ePEAT give us valuable information about the real abilities of patients to transmit an auditory stimulus to the central nervous system, which help us to define expectations with cochlear implant use, assisting us in our decision-making.

Terceira janela da orelha interna: o que significa / Third window: what is it means

A deiscência do canal semicircular superior foi descrita por Minor e cols. em 1998 e tem como definição a ausência de cobertura óssea sobre o canal semicircular superior na zona próxima à duramáter na fossa craniana média, o que seria equivalente a uma terceira janela. Sabe-se que qualquer processo que crie uma comunicação adicional com o labirinto leva a sinais e sintomas clínicos semelhantes, sendo, portanto, denominado terceira janela. Os objetivos deste trabalho são apresentar o conceito de terceira janela, destacar a fisiopatologia, a clínica e os diagnósticos diferenciais, e discutir os achados de imagem, inclusive com casos de nosso serviço. As janelas redonda e oval são as duas aberturas fisiológicas do sistema hidráulico da orelha interna. Medianteuma terceira janela, este sistema é rompido e há alteração da fisiologia do labirinto, gerando sinais e sintomas auditivos e vestibulares. Terceira janela é um novo conceito no campo da otologia. O tratamento por parte do otorrinolaringologista depende da identificação desse distúrbio peloradiologista.

The superior semicircular canal dehiscence was described first time by Minor in 1998 and the definition is the absence of bone cover on superior semicircular canal in the zone adjacent duramater, equivalent third window. Any process that does a labyrinth additional communication produces similar signs and symptoms, denominated third window. The objective of this study was to introduce the third window conception, emphasizing physiology,pathology, clinical issues and different diagnostic, discussing imaging findings, together with cases of owner service. The oval and round windows are physiologies openings hydraulic system of the inner ear. Through a third window, this system is breaking and has a labyrinth physiology disorder, producing vestibular signs and symptoms and hearing loss. Third window is a new conception. Adequate treatment by specialist doctor depends on correct identification by radiologist.

Metastatic involvement of the eighth cranial nerve: a temporal bone study

A total of 251 temporal bones belonging to 130 patients who had malignant disease were revised for evidence of metastatic involvement of the VIIIth nerve within the internal auditory meatus. Twenty-one bones from 14 cases, were recovered, found positive for secondary implication of the VIIIth nerve and included in the study. The pathologic findings of 21 temporal bones with metastatic involvement of the VIIIth nerve are reported and correlated with the clinical history, autopsy findings and pathologic changes in the inner ear. It was concluded that a generalized insight has been developed regarding the magnitude of metastatic [secondary] involvement of the VIIIth cranial nerve which may be more prevalent than realized. Diagnosis of VIIIth nerve involvement by metastatic disease may contribute clues to the prognostic evaluation of the patient's status. Five pattern of implicating the VIIIth nerve by metastatic malignancies within the internal auditory canal are recognized and reported

Toxic labyrinthine reaction: a human temporal bone study

The study material included 240 temporal bones with various pathological conditions involving the middle ear, internal auditory meatus and otic capsule in addition to 40 normal temporal bones to serve as controls. The bones were examined for histomorphologic changes in the inner ear and its fluid content. A significant correlation has been shown between the intralabyrinthine eosinophillic reaction and many of the pathological categories included in the study. It was concluded that speculation were inferred relating the toxic labyrinthine reaction to the immune mechanisms of the inner ear, to the development of secondary endolymphatic hydrops and to the modalities of hearing loss in otitic and meningitic conditions. The pathogenesis of intralabyrinthine eosinophilic exudate was hypothesized and pathophysiology of the consequent hearing loss was discussed

Avaliaçäo da funçäo labiríntica de crianças com distúrbios de linguagem / Evaluation of labyrinth function in childrens with language disorders

Sessenta e quatro crianças com distúrbios de linguagem foram submetidas à avaliaçäo otoneurológica com o objetivo de comparar o valor da electronistagmografia convencional com o da vecto-electronistagmografia como métodos de registro dos movimentos oculares à vestibulometria. Além da elevada incidência de casos coma chados anormais à vestibulometria com ambos os métodos, foi possível concluir que a vectoelectronistagmografia constitui-se no método mais adequado, em virtude de tender a mostrar um número maior de casos com alteraçöes vestibulares e por permitir a exploraçäo funcional dos canais verticais, que podem estar comprometidos em crianças com distúrbios de linguagem

Estudo da funçäo labiríntica em crianças com hipoacusia severa e profunda / Vestibular function in children with severe hearing deficiency

Estudaram-se em 50 crianças com hipoacusia profunda, na faixa etária de 4 a 14 anos - funçäo labiríntica e o desempenho motor, mediante registro eletronistagmográfico - que incluiu o registro dos nistagmos espontâneo, semi-espontâneo, optocinético, posicional e per-rotatório, bem como o rastreio pendular e o estudo do grau de desempenho motor avaliando a coordenaçäo visomotora, a coordenaçäo dinâmica geral, o equilíbrio e a lateralidade (dominância cerebral) das mäos, dos olhos e pés. Mediante uma avaliaçäo da funçäo labiríntica mais ampla que a encontrada na literatura e a análise quantitativa do atraso psicomotor médio, e de cada teste, pôde-se chegar às seguintes constataçöes a respeito da funçäo labiríntica do surdo profundo e de sua provável repercussäo no desempenho motor: que é grande a incidência de achados eletronistagmográficos anormais, independente do provável diagnóstico topográfico (periférico, central ou misto) em todos os testes realizados; que houve atraso do perfil psicomotor, em diferentes proporçöes, em todos os componentes do grupo de estudo, e alta incidência cerebral (lateralidade); que näo ocorreu digerença significativa no grau de desempenho psicomotor em estudo; que apesar de inúmeras correlaçöes dos resultados, os casos em que as provas labirínticas foram normais, näo revelaram desempenho psicomotor significativamente diverso daqueles que apresentaram exames labirínticos anormais; que näo há relaçäo de proporcionalidade entre a preponderância direcional da prova rotatória pendular decrescente e o percentual psicomotor médio

Síndrome de Behçet: relato de um caso clínico / Behçet's syndrome: report of a case

Os autores apresentaram um caso de doença de Behçet com comprometimento auditivo e vestibular, com a presença de sinais sugestivos de localizaçäo central a pesquisa otoneurológica. Devido a ocorrência de manifestaçöes cócleo-vestibulares ser rara, procurou-se enfatizar a necessidade de uma pesquisa otoneurológica acurada

The Influence of Rotatory Movement on the Tissue Catecholamines in Rats

The present study was designed to examine the possible relationship between the function of the labyrinth and the role of the sympathetic nervous system In experimental motion sickness produced by rotatory movement(8O r.p.m.). The catecholamines in the brain, the heart and the adrenal gland of rats were rapidly reduced to one half of normal values following exposure to rotatory movement. The pretreatment with streptomycin and dramamine completely prevented the depletion by the rotatory movement of the catecholamines in the brain, the heart and the adrenal gland, but scopolamine did not prevent the decrease. Bretylium or chlorpromazine signifcantly inhibited reduction of the catechol-amines in both of the brain and the heart. However they did not influence the decrease in the adrenal gland. The reduction of the tissue catecholamines in rotatory movement is presumed to be caused largely by activation of the sympathetic nervous system mediated through labyrinthine stimulation.