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Síndrome vestibular em canídeos
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Orientador(es)
Resumo(s)
A síndrome vestibular é uma apresentação neurológica relativamente comum em Medicina
Veterinária. É definida como o conjunto de sinais clínicos associados a uma doença do
sistema vestibular.
A função do sistema vestibular é traduzir as forças de gravidade e movimento em sinais
neurológicos utilizados pelo encéfalo para a determinação da posição da cabeça no espaço,
e para a coordenação dos movimentos da cabeça com os reflexos motores responsáveis
pela estabilidade postural e ocular. Desta forma, afecções do sistema vestibular resultam,
frequentemente, em alterações posturais da cabeça e corpo, descoordenação motora e
ataxia, e alterações nos movimentos oculares.
O sistema vestibular é constituído por dois componentes funcionais: o componente
periférico, localizado no ouvido interno e no qual se incluem os receptores sensoriais
localizados no labirinto membranáceo e a porção vestibular do nervo craniano VIII; e o
componente central, localizado no tronco cerebral e cerebelo, e no qual se incluem os
núcleos e feixes vestibulares.
Os cães com doença vestibular central apresentam, tipicamente, sinais clínicos adicionais
que reflectem envolvimento do tronco cerebral. Estes podem incluir défices dos nervos
cranianos, parésia, défices nas reacções posturais e estado mental alterado.
É assim possível a diferenciação clínica entre a síndrome vestibular periférica e a síndrome
vestibular central. Este é, aliás, o passo fundamental para a realização de um diagnóstico
diferencial adequado, um plano diagnóstico e terapêutico correcto, assim como para
elaborar considerações sobre o prognóstico. O protocolo terapêutico e o prognóstico são
directamente dependentes da etiologia da disfunção vestibular, apresentando, por isso,
grande variabilidade.
As duas afecções mais comuns, que causam disfunção vestibular central, são neoplasias e
infecção / inflamação; enquanto que em pacientes com sinais vestibulares periféricos, a otite
média / interna e a doença vestibular idiopática são os diagnósticos mais frequentes.
A componente prática da presente dissertação incide na descrição e análise de 8 canídeos
apresentados à consulta no Hospital Escolar da Faculdade de Medicina Veterinária da
Universidade Técnica de Lisboa, com síndrome vestibular. Foram observados 5 canídeos
com síndrome vestibular periférica, um deles com afecção bilateral do sistema vestibular, e 3
canídeos com síndrome vestibular central.
Apesar de algumas dificuldades terem limitado, nalguns casos, a obtenção de um
diagnóstico etiológico definitivo, a realização de um diagnóstico anatómico correcto foi
possível na maioria dos casos.
ABSTRACT - CANINE VESTIBULAR SYNDROME - Vestibular syndrome is a relatively common neurologic presentation in Veterinary Medicine. It is defined as a combination of clinical signs associated with disease of the vestibular system. The function of the vestibular system is to transduce the forces of gravity and movement into neurologic signals that the brain can use to determine the position of the head in space, and to coordinate head movements with the motor reflexes responsible for postural and ocular stability. Thus, lesions of the vestibular system commonly result in abnormal posture of the head and body, motor incoordination and ataxia, and abnormal eye movements. The vestibular system is composed of two functional components: the peripheral component, located in the inner ear, include the sensory receptors located in the membranous labyrinth and the vestibular portion of cranial nerve VIII; and the central component, located in the brainstem and cerebellum, include vestibular nuclei and pathways. Dogs with central vestibular disease typically have additional clinical signs reflective of brainstem involvement. These can include deficits of cranial nerves, paresis, postural reaction deficits and altered mental status. It is then possible to clinically differentiate peripheral vestibular syndrome from central vestibular syndrome. In fact, this is the fundamental step in the elaboration of a proper differential diagnosis, an accurate diagnostic and therapeutical plan, and in the elaboration of prognostic considerations. The treatment and prognosis are directly dependent of the vestibular dysfunction aetiology, thus presenting great variability. The two most common disease processes that cause central vestibular dysfunction are neoplasia and infection / inflammation; whilst the two most common diagnoses in patients with peripheral vestibular signs are otitis media / interna and idiopathic vestibular disease. The practical component of this thesis concerns the study of 8 dogs presented with vestibular syndrome, at the Faculty of Veterinary Medicine Teaching Hospital. Five dogs with peripheral vestibular syndrome, one of which with bilateral disease of the vestibular system, and 3 dogs with central vestibular syndrome were observed. Despite some limitations in the attainment of a definitive etiologic diagnosis in some cases, an accurate anatomic diagnosis was possible in most cases.
ABSTRACT - CANINE VESTIBULAR SYNDROME - Vestibular syndrome is a relatively common neurologic presentation in Veterinary Medicine. It is defined as a combination of clinical signs associated with disease of the vestibular system. The function of the vestibular system is to transduce the forces of gravity and movement into neurologic signals that the brain can use to determine the position of the head in space, and to coordinate head movements with the motor reflexes responsible for postural and ocular stability. Thus, lesions of the vestibular system commonly result in abnormal posture of the head and body, motor incoordination and ataxia, and abnormal eye movements. The vestibular system is composed of two functional components: the peripheral component, located in the inner ear, include the sensory receptors located in the membranous labyrinth and the vestibular portion of cranial nerve VIII; and the central component, located in the brainstem and cerebellum, include vestibular nuclei and pathways. Dogs with central vestibular disease typically have additional clinical signs reflective of brainstem involvement. These can include deficits of cranial nerves, paresis, postural reaction deficits and altered mental status. It is then possible to clinically differentiate peripheral vestibular syndrome from central vestibular syndrome. In fact, this is the fundamental step in the elaboration of a proper differential diagnosis, an accurate diagnostic and therapeutical plan, and in the elaboration of prognostic considerations. The treatment and prognosis are directly dependent of the vestibular dysfunction aetiology, thus presenting great variability. The two most common disease processes that cause central vestibular dysfunction are neoplasia and infection / inflammation; whilst the two most common diagnoses in patients with peripheral vestibular signs are otitis media / interna and idiopathic vestibular disease. The practical component of this thesis concerns the study of 8 dogs presented with vestibular syndrome, at the Faculty of Veterinary Medicine Teaching Hospital. Five dogs with peripheral vestibular syndrome, one of which with bilateral disease of the vestibular system, and 3 dogs with central vestibular syndrome were observed. Despite some limitations in the attainment of a definitive etiologic diagnosis in some cases, an accurate anatomic diagnosis was possible in most cases.
Descrição
Dissertação de Mestrado Integrado em Medicina Veterinária
Palavras-chave
Síndrome vestibular Sistema vestibular Ouvido interno Canídeo Vestibular central Vestibular periférica Vestibular syndrome Vestibular system Inner ear Canine Central vestibular Peripheral vestibular
Contexto Educativo
Citação
Ferreira, R.F.S. (2009). Síndrome vestibular em canídeos. Dissertação de Mestrado. Universidade Técnica de Lisboa, Faculdade de Medicina Veterinária, Lisboa.
Editora
Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária