A carregar...
Publicação
Doença de Menière e deiscências de canais semicirculares
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 798.93 KB | Adobe PDF |
Autores
Orientador(es)
Resumo(s)
A Doença de Menière (DM) é uma síndrome clínica de etiologia desconhecida, sendo caracterizada por episódios recorrentes de vertigem espontânea com surdez neurossensorial unilateral (frequências médias e baixas), acufeno e sensação de plenitude auricular. A hidrópsia endolinfática (HE) é o substrato anatomopatológico da doença (embora não patognomónico) e pode ser diagnosticada in vivo por ressonância magnética (RM), desde 2007. No entanto, os critérios atuais da DM mantêm-se exclusivamente clínicos. A HE consiste na dilatação do espaço endolinfático do labirinto membranoso, que comprime e reduz a amplitude do espaço perilinfático. Estas estruturas do labirinto membranoso estão envolvidas pelo labirinto ósseo, o qual pode apresentar descontinuidades, colocando em contacto direto a dura-máter com o labirinto membranoso, em particular o espaço perilinfático. Foram descritos casos cuja apresentação clínica audiovestibular mimetiza a DM em que se observam deiscências de canais semicirculares (DCS). Esta é definida pela presença de uma descontinuidade do osso que reveste os canais semicirculares do ouvido interno. Coloca-se a hipótese de que a herniação da dura-máter, através de um defeito ósseo do ouvido interno, possa comprimir o labirinto membranoso e a perilinfa, resultando num aumento compensatório da endolinfa (HE), podendo explicar alguns casos de DM. A DCS pode ser identificada por tomografia computorizada (TC) e por RM e a HE por RM. Neste trabalho são avaliadas RM de ouvidos de 9 doentes com diagnóstico de DM definitiva e de 8 indivíduos saudáveis, quanto à presença de DCS. É também avaliada a presença de HE no grupo com DM. Pretende-se saber se a DCS é mais frequente em doentes com DM comparativamente a indivíduos assintomáticos e se, nos doentes com DM, é mais frequente em ouvidos com HE comparativamente a ouvidos sem hidrópsia. Esperamos encontrar um maior número de DCS em ouvidos de doentes com DM, sobretudo na presença de HE.
Menière disease (MD) is a clinical syndrome of unknown etiology, characterized by recurrent spontaneous vertigo episodes with ipsilateral neurossensorial hearing loss (for medium and low frequencies), tinnitus and sensation of aural fullness. The endolymphatic hydrops (EH) is the anatomopathological finding (although not pathognomonic) and can be detected in vivo by cranial-encephalic magnetic resonance imaging (MRI) since 2007. However the actual diagnostic criteria for MD are exclusively clinical. EH is based on the dilatation of the endolymphatic sac within the membranous labyrinth, consequently reducing the perilymphatic sac. These structures are within an ossicular labyrinth that can present some abnormal openings, resulting in some bulging of the dura-mater in the perilymphatic space. Some cases were reported presenting audiovestibular signs and symptoms, like the ones manifested in MD, presenting only semicircular canal dehiscence (SCD), wich is defined as a discontinuity of the bone that forms the semicircular channel in the internal ear. It is hypothesized that the natural plugging of the semicircular canal by the overhanging dura mater could be responsible for the compression of the membranous labyrinth and perilymph, resulting in a compensated endolymphatic hydrops, which could explain some cases of MD. The SCD can be identified by computerized tomography (CT) and MRI and the EH by MRI. In this retrospective study we enrolled 17 patients who underwent an MRI, 9 of these with definitive MD and 8 asymptomatic adults to evaluate them with the intention of finding SCD. It has also been assessed the presence of EH in the patient diagnosed with definitive MD. We propose to establish if the SCD is more frequent in patients diagnosed with definitive MD in comparison with the general asymptomatic adult and, in the patient with MD, if SCD is more prevalent in ear with EH comparing with the ear without. We expect to find a superior number of SCD in patients with MD, especially in concomitant EH.
Menière disease (MD) is a clinical syndrome of unknown etiology, characterized by recurrent spontaneous vertigo episodes with ipsilateral neurossensorial hearing loss (for medium and low frequencies), tinnitus and sensation of aural fullness. The endolymphatic hydrops (EH) is the anatomopathological finding (although not pathognomonic) and can be detected in vivo by cranial-encephalic magnetic resonance imaging (MRI) since 2007. However the actual diagnostic criteria for MD are exclusively clinical. EH is based on the dilatation of the endolymphatic sac within the membranous labyrinth, consequently reducing the perilymphatic sac. These structures are within an ossicular labyrinth that can present some abnormal openings, resulting in some bulging of the dura-mater in the perilymphatic space. Some cases were reported presenting audiovestibular signs and symptoms, like the ones manifested in MD, presenting only semicircular canal dehiscence (SCD), wich is defined as a discontinuity of the bone that forms the semicircular channel in the internal ear. It is hypothesized that the natural plugging of the semicircular canal by the overhanging dura mater could be responsible for the compression of the membranous labyrinth and perilymph, resulting in a compensated endolymphatic hydrops, which could explain some cases of MD. The SCD can be identified by computerized tomography (CT) and MRI and the EH by MRI. In this retrospective study we enrolled 17 patients who underwent an MRI, 9 of these with definitive MD and 8 asymptomatic adults to evaluate them with the intention of finding SCD. It has also been assessed the presence of EH in the patient diagnosed with definitive MD. We propose to establish if the SCD is more frequent in patients diagnosed with definitive MD in comparison with the general asymptomatic adult and, in the patient with MD, if SCD is more prevalent in ear with EH comparing with the ear without. We expect to find a superior number of SCD in patients with MD, especially in concomitant EH.
Descrição
Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2021
Palavras-chave
Doença de Menière Deiscência de canais semicirculares Hidrópsia endolinfática Ressonância magnética Tomografia computadorizada Imagiologia