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Advisor(s)
Abstract(s)
A angiopatia amilóide cerebral, uma doença com um forte componente genético, e com uma
relação íntima com o envelhecimento, carateriza-se pela deposição de matéria amilóide,
nomeadamente péptido Aß, na média e íntima da vasculatura cerebral, fragilizando-a e
predispondo a eventos hemorrágicos intracranianos. Estes depósitos acumulam-se
maioritariamente na microvasculatura arterial cortical posterior, apesar de também poderem
ser encontrados em vasos de maior calibre de outra localização topográfica, assim como em
veias e vénulas cerebrais.
Tratando-se da causa mais comum de hemorragia intracraniana lobar não-hipertensiva na
população idosa, a angiopatia amilóide cerebral tem nesta a sua manifestação clínica mais
comum. Eventos isquémicos, apesar de serem por norma assintomáticos, também estão
presentes no leque de possíveis apresentações clínicas da angiopatia amilóide cerebral.
Uma vez que a sua evolução é caracteristicamente lenta e silenciosa, seria de esperar que os
meios complementares de diagnóstico, quer imagiológicos, quer bioquímicos, oferecessem um
vasto espetro de opções acessíveis, rápidas e eficazes na deteção dos depósitos amilóides, e
suas consequências nefastas na vasculatura cerebral. Todavia, na atualidade, os exames
disponíveis para despiste de angiopatia amilóide cerebral ainda se encontram numa fase
precoce do seu desenvolvimento, e o diagnóstico definitivo de angiopatia amilóide cerebral
apenas pode ser efetuado post-mortem. A PET-PIB (Tomografia de Emissão de Positrões com
Pittsburgh Compound) e a ressonância magnética adjuvada com mapeamentos como o GRE
(Gradient-Recall Echo) e o SWI (Susceptibility-Weighted Imaging) perfilam-se na primeira
linha de exames complementares de diagnóstico direcionados à angiopatia amilóide cerebral,
apesar de ainda não oferecerem um resultado objetivo e eficaz no seu diagnóstico. A análise
do líquido cerebroespinal, através dos níveis de péptido Aß-40, Aß-42 e proteína tau também
se destaca como adjuvante na orientação para o diagnóstico desta doença, porém a sua
especificidade não atinge os níveis desejados.
As medidas terapêuticas direcionadas à prevenção e tratamento da angiopatia amilóide
cerebral também são, atualmente, escassas e pouco eficazes, sendo que o desenvolvimento
de uma possível vacinação, adjuvada com terapêutica farmacológica específica, está a ser
desenvolvida com boas perspetivas. A utilização de terapêutica anticoagulante e/ou antiplaquetária
deve ser levada em conta em casos em que se suspeita de angiopatia amilóide
cerebral, uma vez que pode predispor aos eventos hemorrágicos caraterísticos desta
patologia.
Para a realização deste trabalho, a pesquisa bibliográfica foi realizada através das bases de
dados PubMed, PMC/HIH/NLM, e-medicine, uptodate, e no motor de busca Google
Académico. Esta pesquisa foi efetuada fundamentalmente em português e inglês. Após uma investigação extensa e detalhada foi possível concluir que ainda há um longo
caminho a percorrer no desenvolvimento de meios complementares de diagnóstico rápidos,
acessíveis e eficazes para uma detecção precoce e consequente controlo das possíveis
consequências clínicas da angiopatia amilóide cerebral. Além disso, a inclusão desta patologia
no diagnóstico diferencial e raciocínio clínico da comunidade médica deve ser levada em
conta, não fosse a angiopatia amilóide cerebral uma causa major de hemorragia intracraniana
na população idosa.
Cerebral Amyloid Angiopathy, a disease with a strong genetic component, and a straight relationship with aging, is characterized by the deposition of amyloid matter, mainly Aß peptide, in the brain’s vascular system, especially in the tunica media and intimae, weakening it and predisposing to intracranial hemorrhagic episodes. This phenomenon happens mainly in the posterior arterial micro vascular region, although that can be found in larger blood vessels within other brain regions, as well as in cerebral veins and venules. The most common clinical manifestation of cerebral amyloid angiopathy is a non-hypertensive lobar intracranial hemorrhage, as it represents the main cause for this condition in the older population. Micro-infarcts, although mainly asymptomatic, are also present in the possible clinical presentations of CAA. Cognitive decline, similar to the one that characterizes Alzheimer’s disease, sometimes precedes these episodes. As its clinical progression is usually slow and silent, one could expect a vast range of diagnosis procedures to be available. However, today, the diagnostic exams for CAA are still in an early stage of development, and the definite CAA diagnosis can only be delivered in a post-mortem state. The techniques that appear to be more promising are the PET-PiB (Positron Emission Tomography - Pittsburgh Compound) and the GRE (Gradient-Recall Echo) and SWI (Susceptibility-Weighted Imaging) MRI, though they still don’t provide a definite diagnosis. Cerebrospinal Fluid studies, through the measure of Aß-40, Aß-42 and tau protein levels, may also be an important diagnostic tool, but, for now, its specificity is too low to be considered a reliable option. Although there’s still no effective therapy scheme to treat or prevent the occurrence of CAA, the development of a vaccine directed towards this disease, combined with specific pharmacological therapy, is one of the possible treatment options for this condition in the future. Anticoagulant and antiplatelet treatment should be revised when there’s the possibility of CAA co-morbidity, as it may lead to hemorrhagic episodes. In order to do this work, the bibliographic research was made through the Pub Med, PMC/HIH/NLM, e-medicine uptodate and Academic Google databases. This research was conducted primarily in Portuguese and English. After an extensive and detailed research, I was able to conclude that there’s still a long way to go in order to turn CAA into an affordably and easily diagnosable disease. Besides, the inclusion of this condition in the differential diagnosis and clinical thinking of the medical community should be taken seriously, as it represents a major cause for intracranial hemorrhage, a dreadful pathological event.
Cerebral Amyloid Angiopathy, a disease with a strong genetic component, and a straight relationship with aging, is characterized by the deposition of amyloid matter, mainly Aß peptide, in the brain’s vascular system, especially in the tunica media and intimae, weakening it and predisposing to intracranial hemorrhagic episodes. This phenomenon happens mainly in the posterior arterial micro vascular region, although that can be found in larger blood vessels within other brain regions, as well as in cerebral veins and venules. The most common clinical manifestation of cerebral amyloid angiopathy is a non-hypertensive lobar intracranial hemorrhage, as it represents the main cause for this condition in the older population. Micro-infarcts, although mainly asymptomatic, are also present in the possible clinical presentations of CAA. Cognitive decline, similar to the one that characterizes Alzheimer’s disease, sometimes precedes these episodes. As its clinical progression is usually slow and silent, one could expect a vast range of diagnosis procedures to be available. However, today, the diagnostic exams for CAA are still in an early stage of development, and the definite CAA diagnosis can only be delivered in a post-mortem state. The techniques that appear to be more promising are the PET-PiB (Positron Emission Tomography - Pittsburgh Compound) and the GRE (Gradient-Recall Echo) and SWI (Susceptibility-Weighted Imaging) MRI, though they still don’t provide a definite diagnosis. Cerebrospinal Fluid studies, through the measure of Aß-40, Aß-42 and tau protein levels, may also be an important diagnostic tool, but, for now, its specificity is too low to be considered a reliable option. Although there’s still no effective therapy scheme to treat or prevent the occurrence of CAA, the development of a vaccine directed towards this disease, combined with specific pharmacological therapy, is one of the possible treatment options for this condition in the future. Anticoagulant and antiplatelet treatment should be revised when there’s the possibility of CAA co-morbidity, as it may lead to hemorrhagic episodes. In order to do this work, the bibliographic research was made through the Pub Med, PMC/HIH/NLM, e-medicine uptodate and Academic Google databases. This research was conducted primarily in Portuguese and English. After an extensive and detailed research, I was able to conclude that there’s still a long way to go in order to turn CAA into an affordably and easily diagnosable disease. Besides, the inclusion of this condition in the differential diagnosis and clinical thinking of the medical community should be taken seriously, as it represents a major cause for intracranial hemorrhage, a dreadful pathological event.
Description
Keywords
Angiopatia Amilóide Cerebral Curso Demência Diagnóstico Doença de Alzheimer Epidemiologia Etiologia Fenótipo Hemorragia Intracraniana Prognóstico Tratamento