Bucle vascular de la arteria cerebelosa antero inferior como causa de vértigo. Presentación de caso / Vascular loop of the antero-inferior cerebellar artery as a cause of vertigo. Case presentation

RESUMEN La compresión vascular del nervio vestíbulo-coclear puede manifestarse con una sintomatología variada, incluyendo el vértigo, cuya causa, poco frecuente, son las asas vasculares. Se presenta el caso de un paciente del sexo masculino de 41 años, quien acudió a consulta en el Hospital General Universitario Dr. Gustavo Aldereguía Lima, de Cienfuegos, por presentar hipoacusia y acufenos del oído izquierdo, además vértigos. Se realizó una resonancia magnética simple que mostró un asa vascular en la arteria cerebelosa inferior anterior que ingresaba al conducto auditivo interno, lo cual explicaba la sintomatología. El paciente tuvo mejoría clínica después de tratamiento sintomático. Por lo poco común de la entidad se decidió la presentación del caso.

ABSTRACT Vascular compression of the vestibule-cochlear nerve can manifest itself with a variety of symptoms, including vertigo, the cause of which is infrequent by vascular loops. We present the case of a 41-year-old male patient who came to the Dr. Gustavo Aldereguía Lima University General Hospital in Cienfuegos for hearing loss and tinnitus in the left ear, as well as dizziness. A simple MRI was performed that showed a vascular loop in the anterior inferior cerebellar artery that entered the internal auditory canal, which explained the symptoms. The patient had clinical improvement after symptomatic treatment. Due to the unusual nature of the entity, the presentation of the case was decided.

Análise de zumbido em pacientes com diagnóstico de alça Vascular De VIII par craniano à ressonância nuclear magnética / Analysis of tinnitus in patients diagnosed with vascular loop of the viii cranial nerve on magnetic resonance imaging

Analisar e correlacionar sinais e sintomas auditivos, com ênfase no zumbido, achados audiológicos e sua incidência em indivíduos com alça vascular (AV) de VII/VIII par demonstrado por imagens de RNM de ângulo ponto cerebelar, classificando-os segundo Chavda. Estudo retrospectivo e transversal por meio da análise de dados clínicos dos prontuários de 15 pacientes, correlacionando queixas auditivas e otológicas com resultados encontrados nos exames complementares de Audiometria e RNM a que foram submetidos. Os pacientes que apresentavam alteração do trajeto dos vasos que penetram no MAI, formando alça vascular de VII e/ou VIII par craniano, foram classificados segundo Chavda. Todos os pacientes tinham exame de RNM com diagnóstico de alça vascular do VIII par. Onze deles (73,33%) eram bilaterais. Em 5 pacientes, houve concordância da queixa com os achados à RNM: sintomas bilaterais e alça vascular bilateral. O zumbido gerado pelas estruturas para-auditivas vasculares também são denominados zumbidos pulsáteis. Esses estados levam a fluxo turbulento, gerando o zumbido, que por sua vez é síncrono com o pulso do paciente. Há estudos demonstrando que não há correlação entre zumbido e contato vascular com o VIII par. Encontramos presença de zumbido em aproximadamente 80% dos pacientes com alça vascular, mas nem sempre a queixa coincidiu com a patologia, sendo difícil, portanto, correlacionar queixa e patologia. A presença de alça vascular na RNM não é patológica, mas um achado de exame. A presença do conflito neurovascular do VII/VIII par craniano nas imagens de RNM não justificou por si só os sinais e sintomas otoneurológicos e as al-terações audiovestibulares encontradas nos indivíduos avaliados neste estudo.

To analyze and correlate auditory signs and symptoms, emphasising tinnitus, audiological findings, and their incidence in individuals with vascular loop (AV) of VII/VIII pair demonstrated by MRI images of the cerebellopontine angle, classifying them according to Chavda. A retrospective and cross-sectional study by analyzing clinical data from the medical records of 15 patients, correlating hearing and otological complaints with results found in the complementary tests of Audiometry and MRI. Patients who presented alterations in the path of the vessels that penetrate the IAC, forming a vascular loop of the VII and/or VIII cranial nerve, were classified according to Chavda. All patients had an MRI with a vascular loop of the VIII pair diagnosed. Eleven of them (73.33%) were bilateral. In 5 patients, there was an agreement between the complaint and the MRI findings: bilateral symptoms and bilateral vascular loop. Tinnitus generated by vascular para-auditory structures is also called pulsatile tinnitus. These conditions lead to turbulent flow that causes tinnitus, synchronous with the patient's pulse. There are studies demonstrating there is no correlation between tinnitus and vascular contact with the VIII pair. We found the presence of tinnitus in approximately 80% of patients with vascular loop, but the complaint did not always coincide with the pathology, making it hard to correlate complaints and pathology. The presence of a vascular loop on MRI is not pathological but an examination finding. The neurovascular conflict of the VII/VIII cranial nerve present in the MRI images did not alone justify the otoneurological signs and symptoms and the audiovestibular alterations found in the individuals evaluated in this study.

Role of Magnetic Resonance Imaging in Evaluation of Cerebellopontine Angle Schwannomas

Objectives: The study was designed to evaluate the role ofMagnetic Resonance Imaging (MRI) to localize andcharacterize the MR imaging features of cerebellopontineangle (CPA) schwannomas and to compare withsurgical/histopathological findings.Methodology: Thirty eight patients of clinically suspected &MRI diagnosis cases of CPA Schwannoms were selected inthis cross sectional study in different places of Bangladesh{Mymensingh Medical College Hospital Mymensigh, Sher-EBangla Medical College Hospital, Barisal, Popular DiagnosticCentre Gazipur & Lab Aid diagnostic Centre Barisal. Surgery ofall MR diagnosed cases were done in Dhaka Medial CollegeHospital & National Institute of Neuroscience Hospital, Dhaka}during the period from April 2008 to August 2019. All patientsincluded in the study were subjected to detailed clinical historyand physical examination following which MRI was carried outon 1.5 Tesla & 0.3 Tesla MR machine and the standardprotocol consisted of T1WI, T2WI, DWI and FLAIR images inaxial, sagittal and coronal planes.Results: MRI was erroneous in giving provisional diagnosis ofschwannoma in two cases, which on subsequent surgery andhistopathology was found to be a meningiomas. The sensitivityof MRI for correctly diagnosing vestibular schwannoma was100 % and specificity was 92.86 % with a positive predictivevalue of 94.12 % and accuracy of 96.67 %. MRI is consideredas an excellent noninvasive investigation for CP angleschwannoma’s. It can identify the site and extension of thelesions as well as the characteristic signal.

High-resolution CT combined MR T2-DRIVE sequence imaging in diagnosis of children cochlear nerve dysplasia / 中国介入影像与治疗学

Objective: To investigate the value of high-resolution CT (HRCT) combined with MR T2-DRIVE in diagnosis of cochlear nerve dysplasia (CND) of children. Methods: HRCT and MR T2-DRIVE image data of 43 children (28 unilateral and 15 bilateral) with CND were retrospectively analyzed. The diameters of cochlear nerve canal (CNC) and cochlear nerve were measured with HRCT and T2-DRIVE,respectively. The correlation between CNC diameter and cochlear nerve diameter was analyzed by using Spearman correlation. Results: A total of 58 diseased ears, including 27 pure CND ears and 31 CND accompanied with malformation of inner ear ones, as well as 28 normal ears were found among 43 CND children. HRCT showed CNN stenosis in 45 ears, CNC atresia or absence in 13 ears, internal auditory canal stenosis in 15 ears, including CNC stenosis 12 ears, CNC atresia 2 ears and CNN absence 1 ear. MRI showed abnormal facial nerve morphology in 7 ears, vestibular nerve absence in 1 ear and slender in 1 ear. Among 15 ears of internal auditory canal stenosis, vestibulocochlear nerve was absence in 8 ears and slender in 3 ears, while was normal in 4 ears. Among 58 diseased ears, CNC was demonstrated normal on both HRCT and MRI in 7 ears. The diameters of CNC and cochlear nerve of CND ears were all smaller than those of normal ears (both P=0.001), while no statistically difference of diameters of CNC and cochlear nerve between pure CND ears and CND accompanied with malformation of inner ear ones (P=0.185, 0.140). CNC diameter of all 86 ears was positively correlated with diameter of cochlear nerve (rs=0.773, P<0.001). Taken CNC diameter=1.5 mm as cut-off value, the sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of CND was 84.48% (49/58), 100% (28/28), 100% (49/49) and 75.68% (28/37), respectively. Conclusion: HRCT combined with MR T2-DRIVE can provide diagnostic references for CND of children.

Vértigo como presentación clínica de asa vascular de la arteria cerebelosa antero inferior / Vertigo as a clinical presentation of a vascular loop of the anterior inferior cerebellar artery

Resumen El vértigo es un frecuente motivo de consulta cuyo origen puede ser periférico o central; causas poco frecuentes de este último son las asas vasculares que afectan el VIII par craneal llevando a acúfenos, pérdida de la audición y mareo. Se presenta una mujer de 47 años de edad, quien consulta por un cuadro de mareo, náuseas, pérdida del tono postural, cefalea y parestesia facial, cuyo examen físico revela signos de vértigo periférico, iniciándose tratamiento con antieméticos, anticinetósicos y vasodilatadores que llevan a empeoramiento del cuadro, por lo que se sospecha de patología a nivel de sistema nervioso central (SNC) que ejerce compresión con la vasodilatación. Se realiza una resonancia magnética que muestra un asa vascular en la arteria cerebelosa inferior anterior (AICA) que ingresa al conducto auditivo interno (CAI) explicando la sintomatología y cuyo efecto compresivo de los nervios centrales genera un efecto paradójico con la toma de vasodilatadores. (Acta Med Colomb 2018; 43: 226-229).

Abstract Vertigo is a frequent reason for consultation whose origin can be peripheral or central; infrequent causes of the latter are the vascular loops that affect the VIII cranial nerve leading to tinnitus, hearing loss and dizziness. The case of a 47-year-old woman who consulted for a picture of dizziness, nausea, loss of postural tone, headache and facial paraesthesia, and whose physical examination revealed signs of peripheral vertigo, is presented. Treatment was started with antiemetics, anticinetics and vasodilators that lead to worsening of the condition, for which pathology exerting compression due to vasodilation at the central nervous system (CNS) level, is suspected. An MRI is performed showing a vascular loop in the Anterior Lower Cerebellar Artery (AICA) that enters the Internal Auditory Canal (IAC) explaining the symptomatology and whose compressive effect of the central nerves generates a paradoxical effect with the taking of vasodilators. (Acta Med Colomb 2018; 43: 226-229).

Labyrinthectomy and Vestibular Neurectomy for Intractable Vertiginous Symptoms

Abstract Introduction Labyrinthectomy and vestibular neurectomy are considered the surgical procedures with the highest possibility of controlling medically untreatable incapacitating vertigo. Ironically, after 100 years of the introduction of both transmastoid labyrinthectomy and vestibular neurectomy, the choice of which procedure to use rests primarily on the evaluation of the hearing and of the surgical morbidity. Objective To review surgical labyrinthectomy and vestibular neurectomy for the treatment of incapacitating vestibular disorders. Data Sources PubMed, MD consult and Ovid-SP databases. Data Synthesis In this review we describe and compare surgical labyrinthectomy and vestibular neurectomy. A contrast between surgical and chemical labyrinthectomy is also examined. Proper candidate selection, success in vertigo control and complication rates are discussed on the basis of a literature review. Conclusions Vestibular nerve section and labyrinthectomy achieve high and comparable rates of vertigo control. Even though vestibular neurectomy is considered a hearing sparing surgery, since it is an intradural procedure, it carries a greater risk of complications than transmastoid labyrinthectomy. Furthermore, since many patients whose hearing is preserved with vestibular nerve section may ultimately lose that hearing, the long-term value of hearing preservation is not well established. Although the combination of both procedures, in the form of a translabyrinthine vestibular nerve section, is themost certain way to ablate vestibular function for patients with no useful hearing and disabling vertigo, some advocate for transmastoid labyrinthectomy alone, considering that avoiding opening the subarachnoid space minimizes the possible intracranial complications. Chemical labyrinthectomy may be considered a safer alternative, but the risks of hearing loss when hearing preservation is desired are also high.

Schwanoma gigante do VIII nervo craniano de evolução subaguda: relato de caso / Subacute evolution of giant schwannoma of VIII cranial nerve: case report

O schwanoma vestibular é uma neoplasia que se origina das células de Schwann da porção vestibular do VIII nervo craniano e que corres- ponde a cerca de 10% dos tumores intracranianos e a 80% a 90% daqueles localizados no ângulo pontocerebelar. Apesar do crescimento lento e evolução em geral benigna, estes tumores podem evoluir de maneira desfavorável devido à localização em compartimento anatômico relativamente reduzido no crânio (fossa posterior), o que pode levar a compressão de estruturas nobres (como o tronco encefálico) e a desenvolvimento de hidrocefalia obstrutiva, especialmente nos raros casos de schawanomas gigantes (> 40 mm). Apresentamos relato de caso de paciente com quadro de tinnitus e hipoacusia à esquerda que evoluiu de forma subaguda com alterações do humor, da cognição e da marcha cujo diagnóstico final foi de schwanoma gigante do VIII nervo craniano.

Vestibular schwannoma is a Schwann cells neoplasia of the vestibular branch of the VIII cranial nerve and it accounts for 10% of intracranial tumours and to 80%-90% of those located at the cerebellopontine angle. Despite slow growth and usual benign evolution, unfavourable outcomes may occur, especially in the rare cases of giant schwanno- mas (> 40mm). Owing the fact that this tumours are located in a relatively narrow space (posterior fossa), giant schwannomas may compress noble areas (as the brainstem), which can also cause obstructive hydrocephalus. We discuss a case report of a 48 years old woman complaining of left-sided hearing loss and tinnitus that developed a subacute cognitive impairment, mood disorder and gait disturbance, diagnosed with giant schwannoma of the VIII nerve.

The First Case of Vestibulocochlear Neuritis in a Patient with Acquired Immunodeficiency Syndrome in Korea / 감염과화학요법

The incidence of human immunodeficiency virus (HIV) infections continue to increase throughout the world. Although neurologic complications are frequent in individuals with HIV infection or acquired immunodeficiency syndrome (AIDS), vestibulocochlear neuritis is still a relatively rare manifestation. We report the first case of vestibulocochlear neuritis occurring in an AIDS patient in Korea.

Clinical observation of keyhole neurovascular decompression on diagnosis and treatment of vestibular paroxysmia / 中国耳鼻咽喉头颈外科

[ABSTRACT]OBJECTIVETo evaluate the diagnostic value and curative effect of keyhole neurovascular decompression with local anesthesia for vestibular paroxysmia.METHODSOf 40 patients with trigeminal neuralgia, hemifacial spasm and glossopharyngeal neuralgia, 8 of them combined with vestibular paroxysmia underwent keyhole neurovascular decompression under local anesthesia to explore the vascular compression of acoustic nerve root and have the neurovascular decompression. The evaluation of the vertigo after operation was performed with symptom report card. The patients were followed-up for 36 to 61 months. RESULTSThe vessels compressing the root zone of the vestibular nerve were found in 8 patients with vestibular paroxysmia, of whom 7 patients had the vascular compression vertigo induced during operation and the vertigo was disappeared after operation, moreover, one patient had no vascular compression vertigo induced during operation and the vertigo was not changed after operation. With the average follow-up of 57 months, of 8 patients with vestibular paroxysmia, 7 patients had no recurrence of the vertigo, and the effective control rate was 87.5%.CONCLUSION Local anesthesia keyhole neurovascular decompression was not only an effective way for treating vestibular paroxysmia and controlling the vertigo, but also had certain clinical significance in the diagnosis of vestibular paroxysmia.

El vértigo como primer síntoma de un infarto cerebeloso / The dizziness as the first symptom of a cellebelar stroke

Introducción: El vértigo es un motivo frecuente de consulta en los servicio de urgencias, por lo tanto es primordial para iniciar un tratamiento adecuado diferenciar un origen periférico de uno central. La historia clínica y la exploración neurológica completa son fundamentales para llegar a un diagnóstico, ya que las pruebas de imagen tienen una baja sensibilidad en la fase aguda y no siempre están disponibles en los servicios de urgencias. Objetivo: Presentar el caso clínico de una paciente de 74 años con vértigo agudo que sugiere inicialmente un origen periférico, pero que se debe a un infarto cerebeloso. Diseño: Reporte de caso. Materiales y métodos: Se presenta el caso de una paciente de 74 años que acude a urgencias por presentar de manera súbita vértigo objetivo con los movimientos cefálicos, intenso cortejo vegetativo, sin síntomas otológicos, con factores de riesgo cardiovascular importantes; al examen físico nistagmo horizontal derecho, no agotable, dismetría, disdiadococinesia izquierda e inestabilidad marcada que le impide la bipedestación. En tomografía craneal, se observa hipodensidad en región superior del hemisferio cerebeloso izquierdo sugestiva de lesión isquémica aguda en territorio vascular de la arteria cerebelosa superior. Resultados: Se diagnosticó mediante resonancia magnética nuclear, infarto isquémico en fase subaguda en el territorio de arteria cerebelosa superior izquierda. Conclusiones: Es importante diferenciar el vértigo aislado por causa vascular de trastornos más benignos que se relacionan con el oído interno, ya que la estrategia terapéutica y el pronóstico difieren considerablemente

Introduction: Vertigo is a frequent reason for consultation in the emergency department, therefore it is essential to differentiate between peripheral and central origin to initiate a suitable treatment. The clinical history and neurological examination are essential to reach a diagnosis, because imaging tests have low sensitivity in the acute phase and are not always available in the Emergency Department. Objective: To present the clinical case of a 74 year old patient with acute vertigo which initially suggested a peripheral origin, but it was due to an acute cerebellar infarction. Design: Case report. Materials and methods: We present the case of a patient of 74 years who came to the emergency department because of a sudden objective vertigo with was presented with head movements, severe vegetative symptoms without otologic symptoms. Important cardiovascular risk factors was identified; physical examination revealed an inexhaustible, horizontal, right nistagmus; dysmetria, left dysdiadochokinesia and marked instability. In tomography, a suggestive image of acute ischemic injury in vascular territory of the superior cerebellar artery hemisphere was seen. Results: A subacute ischemic stroke in the territory of the left superior cerebellar artery was diagnosed by nuclear magnetic resonance. Conclusions: It is important to differentiate isolated vertigo caused by more benign inner ear disease from those caused by vascular disorders, since therapeutic strategy and prognosis differ considerably.

Comparison of Audiovestibular Dysfunction in Patients of Acute Unilateral Peripheral Vestibulopathy with and without Vascular Risk Factors / 대한평형의학회지

BACKGROUND AND OBJECTIVES: Etiology of acute unilateral peripheral vestibulopathy (AUPV) includes virus, ischemia, and autoimmune. As anatomical distribution is similar between vasculature and innervation, AUPV with vascular risk factors could be ischemic origin. We investigated the pattern of audiovestibular dysfunction to explore the influence of risk factors on AUPV. MATERIALS AND METHODS: We collected records of 162 AUPV patients from 2011 to 2013 who were admitted within 7 days from vertigo onset and diagnosed as AUPV by caloric test and neuro-otologic examination. Vascular risk factors are stroke history, hypertension, diabetes, body mass index >25, age >60, and vertebrobasilar stenosis. Bedside examination includes spontaneous nystagmus grade, head impulse test, head shaking test. Results of rotatory chair test (n=125), caloric test (n=162), cervical (n=33) and ocular (n=23) vestibular evoked myogenic potential (VEMP), subjective visual vertical (SVV) (n=91), and pure tone audiometry (PTA) (n=62) are collected. RESULTS: Abnormalities of PTA are found more in patients with vascular risk factor than without any risk factor. Specifically, hypertension (p=0.008) and old age (p=0.025) are associated with PTA abnormality (p=0.006). Tilt angle of vertical is larger in risk factor group (p=0.019). The number of vascular risk factor correlates with abnormalities of PTA (p=0.025) and tilt angle of SVV. Results of bedside examination, rotatory chair test, caloric test, cervical and ocular VEMP are not associated with vascular risk factors. CONCLUSION: AUPV patients with vascular risk factors have more extensive involvement of audiovestibular function. Ischemic etiology may contribute to pathogenesis of extensive AUPV.

MRI analysis of vestibulocochlear neurovascular compression in 28 patients with vestibular paroxysmia / 中华神经科杂志

Objective To analyze the MRI characteristics of vestibulocochlea neurovascular compression in patients with vestibular paroxysmia (VP) and to investigate the effect of the compression,its site and degree,on the occurrence of VP.Methods Twenty-eight cases of VP (VP group) and 28 cases of vertiginous patients other than VP (control group) were retrospectively reviewed.Three dimensional magnetic resonance angiography (3D-MRA) was performed and the data were used for neurovascular crosscompression (NVCC) analysis.The frequency and type of NVCC,the origin of the offending vessel and the distance between compression site and brainstem were compared between the two groups.Results The frequency of NVCC was 96.4％ (27/28) in VP group,with a significant difference compared with control group (13/28,46.4％ ;x2 =17.15,P ＜0.01).The most common NVCC type was vascular loop compression at vestibulocochlear nerve (15/35,42.9％).Anterior inferior cerebellar artery was the most common offending vessel (25/35,71.4％) in VP group.There were no significant differences between the two groups in the type of NVCC or the origin of the offending vessel.The frequency on the distortion and (or) displacement of vestibulocochlear nerve which was severely compressed by vessel in VP group (7/56,12.5％) was significantly higher than that in control group (0; P =0.013).The distance between compression site and brainstem was (8.57 ± 5.08) mm in VP group,and (8.93 ± 4.64) mm in control group,showing no significant difference.The ratio that the distance was less than 15 mm between compression site and brainstem in unilateral NVCC of VP group (100％) was significantly higher than unilateral NVCC of control group (7/10,P =0.033).Conclusions The VP patients have higher NVCC incidence and the most common NVCC type is vascular loop compression at vestibulocochlear nerve which is mainly caused by anterior inferior cerebellar artery.NVCC in VP patients mostly occurs in the central myelin portion of vestibulocochlear nerve.The site and degree of neurovascular compression may relate to the occurrence of VP.

Vestibular schwannoma: 825 cases from a 25-year experience

Introduction: Acoustic nerve tumors have been recognized as a clinico-pathologic entity for at least 200 years, and they represent 90% of cerebellopontine angle diseases. Histologically, the tumors are derived from Schwann cells of the myelin sheath, with smaller tumors consisting of elongated palisade cells, while in large tumors, cystic degeneration can be found in the central areas, possibly due to deficient vascularization. We retrospectively reviewed 825 cases of vestibular schwannomas, reported between January 1984 and August 2006, in which the patients underwent surgery to remove the tumor. Objective: To evaluate signs, symptoms, aspects of clinical diagnosis, including the results of audiological and imaging studies, and surgical techniques and complications. Methods: A retrospective chart review. The medical records of all patients undergoing surgical treatment for schwannoma during the period indicated were reviewed. Results and Conclusion: Hearing loss was the first symptom reported in almost all cases, and tumor size was not proportional to the impairment of the auditory threshold. The surgical techniques allowed safe preservation of facial function. In particular, the retrolabyrinthine route proved useful in small tumors, with 50% preservation of hearing...

Achados otoneurológicos em pacientes com diagnóstico de alça vascular de VIII par craniano na ressonância magnética / Neurotology findings in patients with diagnosis of vascular loop of cranial nerves VIII in magnetic resonance imaging

INTRODUÇÃO: A compressão vascular por vasos redundantes sobre o VIII par craniano vem sendo estudada desde a década de 80, e diversos autores propuseram correlações entre a compressão e os achados otoneurológicos (vertigem, zumbido, hipoacusia, audiometria e achados eletrofisiológicos). OBJETIVO: Analisar e correlacionar os diferentes sinais e sintomas otoneurológicos, os achados audiológicos e sua incidência em indivíduos com diagnóstico de alça vascular (AV) de VIII par craniano por Ressonância Magnética (RM). MÉTODO: Estudo retrospectivo através da análise de prontuários de 47 pacientes atendidos no ambulatório de Otoneurologia do Hospital de Clínicas da UFPR. Todos os pacientes possuíam exames de RM com imagens compatíveis com AV de VIII par craniano. RESULTADOS: O zumbido foi o sintoma mais frequente, em 83 por cento dos pacientes, seguido de hipoacusia (60 por cento) e vertigem (36 por cento). A audiometria apresentava alterações em 89 por cento, o PEATE em 33 por cento e o VENG em 17 por cento dos pacientes. Não foi encontrada relação estatisticamente significante entre o zumbido ou a hipoacusia e a presença de AV na RM. Somente 36 por cento dos pacientes tinham queixas de vertigem, o principal sintoma descrito na teoria da compressão vascular do VIII par. Tanto na Audiometria quanto no PEATE não foi encontrada relação estatisticamente significante entre o exame e a presença de AV na RM. CONCLUSÃO: Os resultados mostram independência entre os achados da RM, quadro clínico e resultados audiológicos (p>0,05) sugerindo que não exista relação direta e exclusiva entre o diagnóstico de alça vascular na RM e o quadro clínico otoneurológico correspondente.

INTRODUCTION: The vascular compression by redundant vessels under the VIII cranial nerves has been studied since the 80's, and many authors proposed correlations between the compression and the otoneurological findings (vertigo, tinnitus, hypoacusis, audiometry and electrophysiological findings). OBJECTIVE: Analyze and correlate the different signs and otoneurological symptoms, the audiological findings and its incidence over individuals with Vascular Loop (VL) diagnosis of VIII cranial nerves by magnetic resonance imaging (MRI). METHOD: Retrospective study through the analysis of medical records of 47 patients attended in the otoneurology clinic of Clinical Hospital of UFPR. All the patients have MRI exams with compatible pictures of VL of the VIII cranial nerves. RESULTS: The tinnitus was the most frequent symptom, in 83 percent of the patients, followed by hypoacusis (60 percent) and vertigo (36 percent). The audiometry presented alterations in 89 percent, the brainstem evoked auditory potential in 33 percent and the vecto-electronystagmography in 17 percent of the patients. Was not found statistically significant relation between the buzz or hypoacusis, and the presence of VL in MRI. Only 36 percent of patients had complaints of vertigo, the main symptom described in theory of vascular compression of the VIII pair of nerve. As in the audiometry and in brainstem evoked auditory potential was not found a statistically significant relation between the exam and the presence of the VL in the RMI. CONCLUSION: The results show independence between the findings of the RMI, clinical picture and audiological results (p>0,05) suggesting that there are no exclusive and direct relation between the diagnosis of vascular loop in the MRI and the clinical picture matching.

Estenosis del canal auditivo interno (CAI): hallazgos por imagen / Internal auditory canal (IAC) stenosis: imaging findings

Objetivos: Describir los hallazgos por imagen en tomografía computarizada (TAC ) y resonancia magnética (RM) en una paciente con estenosis del CAI. Describir el desarrollo embriológico de las estructuras del CAI y la historia natural de la estenosis del CAI . Métodos: Se presenta el caso de una paciente de 4 años de edad con diagnóstico de cardiopatía congénita, hipoacusia neurosensorial (HNS ) y otitis media recurrente bilateral, y a quien se realizó TAC del hueso temporal con imágenes axiales y reconstrucciones coronales, en las cuales se observa disminución del diámetro de la luz del CAI izquierdo (menor de 2 mm), ausencia del CAI derecho y estructuras del oído interno de características normales, compatibles con estenosis del CAI izquierdo. Las imágenes de RM demuestran la estenosis del CAI izquierdo, sin observarse las estructuras nerviosas dentro de éste, compatible con hipoplasia/aplasia del nervio vestibulococlear. Resultados: Se describen brevemente la patología, el origen embriológico y la importancia de la asociación de la estenosis delCAI a hipoplasia/aplasia del nervio vestibulococlear en el diagnóstico diferencial de las causas de HNS , que contraindican la realización de implante coclear. Conclusiones: La estenosis del CAI e hipoplasia/aplasia del nervio vestibulococlear es un diagnóstico para tener en cuenta dentro de las causas de HNS , y su diagnóstico puede realizarse a través de TAC y de RM.

Objectives: To describe the computed tomography (CT) and magnetic resonance (MR) findings in a patient with a diagnosis of internal auditory canal (IAC) stenosis. To describe the embryological development of the IAC structures and the natural history of IAC stenosis. Methods: A 4 year old girl presents with sensorineural hearing loss and bilateral recurrent otitis media. The temporal bone CT shows diminished left IAC diameter (less than 2 mm),right IAC absence and normal inner ear structures. These findings are pathognomonic for left IAC stenosis. The MR findings include left IAC stenosis and IAC neural structures absence secondary to aplasia of the vestibulocochlear nerve on each IAC . Results: Hypoplasia/aplasia of the vestibulocochlear nerve in association with IAC stenosis is an important consideration in the differential diagnosis of sensorineural hearing loss, as it is a relative contraindication for cochlear implant placement. Conclusions: IAC stenosis and vestibulocochlear nerve hypoplasia/aplasia must be excluded as an etiology of sensorineural hearing loss. The diagnosis can be made by CT and MR.

Transmission electron microscopy studies of the vestibulocochlear nerve in chronic diabetic rats / Estudios de microscopía electrónica de transmisión del nervio vestibulococlear en ratas diabéticas crónicas

It is widely described in the literature that diabetic patients present hearing impairment. Despite the histological alterations of the internal ear structures in these patients as well as in experimental models of diabetes, to the best of our knowledge, an histological evaluation of the vestibulocochlear nerve have not been performed. In the present study, ultrastructural alterations are described and compared between a spinal nerves and a cranial nerve in rats with chronic induced diabetes. Male Wistar rats (n = 12), fed with standard diet from the animal care facility at 42 days of age were used. Induced diabetic animals (n=6) were fasted for 12 hours prior to being injected intraperitoneally with streptozotocin (STZ - 60mg/kg) in a single dose. Control animals (n=6) received (0.01 mol/l citrate buffer, pH 4.5) vehicle alone. Ten weeks after STZ injection the animals were perfused intracardially with Karnovsky solution. Right and left vestibulocochlear nerves were dissected and histologically processed for epoxy resin embedding. Samples were imaged with the transmission electron microscope. Large myelinated fibers with morphological signs of axonal atrophy in the vestibulocochlear nerves were readily observed. These results suggest that chronic STZ-induced diabetes in rats caused alterations in the myelinated fibers and Schwann cells, compatible to the classic diabetes signs and symptoms. Morphological alterations of the vestibulocochlear nerve in diabetes is described for the first time and contributes information for a better understanding of why there are changes in hearing observed in diabetic patients.

Se ha descrito ampliamente en la literatura que los pacientes diabéticos presentan discapacidad auditiva. En estos pacientes, a pesar de las alteraciones histológicas de las estructuras del oído interno, así como en modelos experimentales de diabetes, que mejoran nuestro conocimiento, la evaluación histológica del nervio vestibulococlear no ha sido realizada. Se describen y comparan las alteraciones ultraestructurales entre un nervio espinal y uno craneal en ratas con diabetes crónica inducida. Fueron utilizadas 12 ratas Wistar machos, de 42 días de edad, alimentadas con dieta estándar. Los animales diabéticos inducidos (n = 6) se mantuvieron en ayuno por 12 horas antes de ser inyectados por vía intraperitoneal con estreptozotocina (STZ - 60mg/kg) en una sola dosis. Los animales control (n = 6) sólo recibieron inyección de 0.01 mol/l buffer, citrato pH 4,5. Diez semanas después de la inyección de STZ, los animales fueron perfundidos intracardiacamente con solución de Karnovsky. Los nervios vestibulococlear derecho e izquierdo fueron disecados y procesados histológicamente para ser incluidos en resina epoxy. Las muestras fueron estudiadas con microscopio electrónico de transmisión. Fueron observadas fácilmente, grandes fibras mielinizadas con signos morfológicos de atrofia axonal en los nervios vestibulococlear. Estos resultados sugieren que la diabetes crónica inducida por STZ en ratas causó alteraciones en las fibras mielínicas y células del neurilema, compatible, con los signos y síntomas clásicos de la diabetes. Alteraciones morfológicas del nervio vestibulococlear en la diabetes son descritas por primera vez, lo que aporta información para una mejor comprensión de por qué hay cambios en la audición en los pacientes diabéticos.

The Association of Anterior Inferior Cerebellar Artery in Internal Auditory Canal with Tinnitus and Hearing Loss

BACKGROUND AND OBJECTIVES: Tinnitus is a common disorder, but the etiology of this disorder remains unknown. The objective of this study was to assess the correlation between anatomical type and the thickness of the anterior inferior cerebellar artery (AICA) loop with tinnitus, using 3D-fast imaging employing steady state acquisition magnetic resonance image (MRI). MATERIALS AND METHODS: 74 patients with tinnitus and 82 asymptomatic controls were included in this study. Otologic symptoms, which was measured based on the results of a pure tone audiometry, were reviewed. We evaluated the position and thickness of the AICA vascular loop in 3D-FIESTA MRI using two scoring systems. The first system was Chavda classification based on the anatomical location of the AICA loop. The second scoring system was used to measure the thickness of the AICA loop. The AICA loops were classified into two groups based on thickness, thinner than adjacent facial nerve and thicker than the facial nerve. RESULTS: Ears with type I, II AICA loops showed significantly higher rates of tinnitus than those with type III. There was no association between the type of AICA loop and subtype of tinnitus (pulsatile, nonpulsatile). There was no association between the type of tinnitus and hearing loss. Ears with thinner AICA loop had a higher rate of tinnitus than those with thicker AICA loop. CONCLUSIONS: The type I, II and thinner AICA loop was significantly correlated with tinnitus. Compression of VIIIth cranial nerve by AICA loops at a cerebellopontine angle and impaired blood flow through the vessel may be the pathophysiology of tinnitus.

The Association of Anterior Inferior Cerebellar Artery in Internal Auditory Canal with Tinnitus and Hearing Loss

BACKGROUND AND OBJECTIVES: Tinnitus is a common disorder, but the etiology of this disorder remains unknown. The objective of this study was to assess the correlation between anatomical type and the thickness of the anterior inferior cerebellar artery (AICA) loop with tinnitus, using 3D-fast imaging employing steady state acquisition magnetic resonance image (MRI). MATERIALS AND METHODS: 74 patients with tinnitus and 82 asymptomatic controls were included in this study. Otologic symptoms, which was measured based on the results of a pure tone audiometry, were reviewed. We evaluated the position and thickness of the AICA vascular loop in 3D-FIESTA MRI using two scoring systems. The first system was Chavda classification based on the anatomical location of the AICA loop. The second scoring system was used to measure the thickness of the AICA loop. The AICA loops were classified into two groups based on thickness, thinner than adjacent facial nerve and thicker than the facial nerve. RESULTS: Ears with type I, II AICA loops showed significantly higher rates of tinnitus than those with type III. There was no association between the type of AICA loop and subtype of tinnitus (pulsatile, nonpulsatile). There was no association between the type of tinnitus and hearing loss. Ears with thinner AICA loop had a higher rate of tinnitus than those with thicker AICA loop. CONCLUSIONS: The type I, II and thinner AICA loop was significantly correlated with tinnitus. Compression of VIIIth cranial nerve by AICA loops at a cerebellopontine angle and impaired blood flow through the vessel may be the pathophysiology of tinnitus.

Alterações no sistema vestibulococlear decorrentes da exposição ao agrotóxico: revisão de literatura / Vestibulocochlear system alterations caused by exposure to pesticides: a literature review

Os agrotóxicos são amplamente utilizados no meio rural e sua larga utilização, desprovida de medidas de biossegurança apropriadas, vem provocando impactos potenciais tanto para a degradação ambiental quanto para o organismo humano, aumentando a incidência de intoxicações ocupacionais. O objetivo do presente estudo foi revisar e discutir a respeito da exposição aos agrotóxicos e sua influência na função e estrutura do sistema auditivo. Foram revisados periódicos nacionais e internacionais relevantes indexados no PubMed, Medline, Bireme e LILACS, assim como capítulos de livros e dissertações publicados no período entre 1987 e 2009. As pesquisas sugerem que a exposição, principalmente crônica, aos agrotóxicos induz a alterações funcionais no sistema vestibulococlear, manifestando ainda uma série de sinais e sintomas. Apesar da escassez de dados sobre a influência do organofosforado nas características morfológicas do aparelho auditivo, os estudos indicam que a exposição de caráter agudo aos agrotóxicos pode também ser responsável por alterações no sistema auditivo, caracterizadas por lesões estruturais na cóclea, principalmente nas células ciliadas externas.

Pesticides are widely used in agriculture, and the widespread application of these agents, without the appropriate use of bio-security measures, has been causing potential impacts for environmental degradation, as well as for the human organism, increasing the incidence of occupational poisoning. The aim of the present study was to review the available literature and to carry out a discussion regarding pesticides exposure and its harmful effects on the auditory system's function and structure. Relevant national and international journals indexed in PubMed, Medline, Bireme and LILACS were reviewed, as well as book chapters and dissertations published between 1987 and 2009. The available data suggest that chronic exposure to pesticides lead to functional alterations in the vestibulocochlear system, as well as a series of signs and symptoms. In spite of the scarce data describing organophosphorus influence on morphological characteristics of the auditory system, the literature suggest that acute exposure to pesticides can also be responsible for auditory system alterations, characterized by structural lesions in the cochlea, mainly in outer hair cells.

Risk factors associated with vestibulocochlear nerve schwannoma: systematic review / Fatores de risco associados ao Schwannoma do nervo vestibular: revisão sistemática

The vestibulocochlear nerve schwannoma (VS) is a benign tumor that stems from the edge of the Schwann´s sheath. It is considered the most frequent intracranial benign tumor, of low lethality rate and unknown etiology. AIM: to identify risk factors associated with VS. STUDY DESIGN: systematic review. METHODS: electronic search of studies using the following key words: "risk", "schwannoma", "vestibular", "neuroma" and "acoustic". All original articles on epidemiological studies published in Portuguese, English or Spanish describing measures of association were included. RESULTS: twenty case-control studies were found, most of them published in the United States. The analysis of those studies shows educational level, household income, occupation, exposure to ionizing radiation and noise, allergic diseases as well as the use of both cellular and cordless phones as risk factors for the VS. CONCLUSION: methodological limitations and lack of precision in the findings impose limits to definitive conclusions concerning those risk factors. The current study contributes with information which can subsidize decisions related to the methodology to be used, having in mind new investigations on risk factors for VS. Therefore, it is of great help for knowledge improvement in this field.

O Schwannoma do nervo vestibular (SV) é um tumor benigno que se origina da bainha de Schwann do VIII par craniano. É o tumor benigno intracraniano mais frequente, de baixa letalidade e etiologia obscura. OBJETIVO: Identificar fatores de risco associados ao SV. DESENHO DO ESTUDO: Revisão sistemática. MATERIAL E MÉTODO: Identificação de estudos em bases de dados eletrônicos utilizando as palavras-chaves "risk", "risco", "schwannoma", "vestibular", "neuroma" e "acoustic". Incluíram-se artigos originais de pesquisa epidemiológica publicados em português, espanhol ou inglês, que referiam alguma medida de associação. Foram comparados e analisados aspectos metodológicos e resultados dos estudos. RESULTADOS: Foram localizados 20 estudos do tipo caso-controle, sendo a maioria publicada nos Estados Unidos. A análise dos estudos revela como fatores de risco para o SV o nível educacional, renda familiar, ocupação, exposição à radiação ionizante e ao ruído, doença alérgica e uso de telefone celular e fixo sem fio. CONCLUSÕES: Limitações metodológicas e imprecisão dos achados impõem limites a conclusões definitivas sobre os fatores de risco associados ao SV. O presente estudo contribui com informações que podem subsidiar decisões metodológicas para novas investigações sobre fatores de risco para SV e, assim, colabora para o avanço do conhecimento na área.