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Abstract(s)
A hipoperfusão cerebral crónica é uma condição que tem vindo a ganhar cada vez mais interesse da comunidade médica internacional devido ao reconhecimento cada vez maior de que é uma patologia capaz de causar défices cognitivos ligeiros vasculares, que podem por fim evoluir para demência vascular. Normalmente a unidade neurovascular impede que a perfusão cerebral seja reduzida abaixo de valores críticos, no entanto há um conjunto de factores de risco que em conjunto podem ultrapassar os mecanismos de defesa e reduzir o fluxo sanguíneo cerebral para valores insuficientes ao normal funcionamento cerebral. O mais importante factor que provoca a redução do fluxo sanguíneo cerebral é o envelhecimento, o que faz prever que com uma população envelhecida aumente a sua incidência e prevalência.
A hipoperfusão cerebral crónica global parece provocar défices cognitivos dos vários domínios cognitivos, apresentando uma preferência pelas funções cognitivas executivas. A hipoperfusão de um hemisfério é capaz de provocar défices cognitivos pelos quais esse hemisfério é responsável. As perdas cognitivas parecem ser reversíveis quando a hipoperfusão cerebral é revertida.
As alterações que a hipoperfusão cerebral crónica provoca no cérebro ainda não são completamente compreendidas, sendo no entanto possível perceber que elas passam pela alteração da barreira hematoencefálica, dano neuronal, reacção astrocitária, activação microglial, stress oxidativo e lesões da matéria branca. Serão essas alterações que vão provocar os défices cognitivos observados nos pacientes com hipoperfusão cerebral crónica.
Para o diagnóstico desta patologia é importante a história clínica para avaliar se a pessoa tem os factores de risco capazes de provocar hipoperfusão cerebral crónica, sendo possível complementar essa informação com a avaliação da condição hemodinâmica cerebral, existindo vários métodos de imagem com esse fim, tendo cada um vantagens e desvantagens.
Actualmente não existe um tratamento aprovado para o tratamento da hipoperfusão cerebral crónica, sendo por isso importante apostar nos métodos preventivos, incidindo nos factores de risco reversíveis capazes de a provocar.
Por fim, combinando estes conhecimentos existentes sobre a hipoperfusão cerebral crónica, eu tentei elaborar um conjunto de orientações que podem ser utilizados pelos profissionais de saúde com o objectivo de reduzir o impacto desta patologia na sociedade.
Apesar das informações que ainda faltam esclarecer nesta área, já é possível perceber que este é um tema relevante na medicina actual, com perspectivas de aumentar ainda mais a sua importância no futuro, sendo indispensável já no presente desenvolver estratégias para o seu controlo.
Chronic cerebral hypoperfusion is a condition that has been gaining increasing interest of the international medical community due to the growing recognition that it is a disease that can cause vascular mild cognitive impairment, which may eventually evolve into vascular dementia. Normally the neurovascular unit prevents that the cerebral perfusion is reduced below critical values, however there are a number of risk factors that together can overcome the defense mechanisms and reduce the cerebral blood flow to insufficient values off the brain normal functioning. The most important factor that causes the reduction of cerebral blood flow is aging, which anticipates that with an aging population it will increase its incidence and prevalence. The global chronic cerebral hypoperfusion appears to induce cognitive deficits in multiple cognitive domains, with a preference for executive cognitive functions. The hypoperfusion of one hemisphere is capable of causing cognitive deficits by which this hemisphere is responsible. Cognitive losses appear to be reversible when cerebral hypoperfusion is reversed. Changes that the chronic cerebral hypoperfusion causes in the brain are not yet fully understood, it is however possible to see that they pass by altering the blood-brain barrier, neuronal damage, astrocytic reaction, microglial activation, oxidative stress and white matter lesions. Are these changes that will cause the cognitive deficits observed in patients with chronic cerebral hypoperfusion. For the diagnosis of this condition it is important to take the clinical history to assess whether the person has risk factors that can cause chronic cerebral hypoperfusion, which can be supplemented with the evaluation of the cerebral hemodynamics, and there are several imaging methods for this purpose, each having advantages and disadvantages. There is currently no approved treatment for the treatment of chronic cerebral hypoperfusion and is therefore important to invest in preventive methods, focusing on reversible risk factors capable of causing it. Finally, combining these existing knowledge on chronic cerebral hypoperfusion, I tried to develop a set of guidelines that can be used by health professionals with the aim of reducing the impact of this disease on society. Despite the information still left to clarify in this area, it is already possible to see that this is an important issue in modern medicine, with prospects of further increase in its importance in the future, being essential in the present to develop strategies for their control.
Chronic cerebral hypoperfusion is a condition that has been gaining increasing interest of the international medical community due to the growing recognition that it is a disease that can cause vascular mild cognitive impairment, which may eventually evolve into vascular dementia. Normally the neurovascular unit prevents that the cerebral perfusion is reduced below critical values, however there are a number of risk factors that together can overcome the defense mechanisms and reduce the cerebral blood flow to insufficient values off the brain normal functioning. The most important factor that causes the reduction of cerebral blood flow is aging, which anticipates that with an aging population it will increase its incidence and prevalence. The global chronic cerebral hypoperfusion appears to induce cognitive deficits in multiple cognitive domains, with a preference for executive cognitive functions. The hypoperfusion of one hemisphere is capable of causing cognitive deficits by which this hemisphere is responsible. Cognitive losses appear to be reversible when cerebral hypoperfusion is reversed. Changes that the chronic cerebral hypoperfusion causes in the brain are not yet fully understood, it is however possible to see that they pass by altering the blood-brain barrier, neuronal damage, astrocytic reaction, microglial activation, oxidative stress and white matter lesions. Are these changes that will cause the cognitive deficits observed in patients with chronic cerebral hypoperfusion. For the diagnosis of this condition it is important to take the clinical history to assess whether the person has risk factors that can cause chronic cerebral hypoperfusion, which can be supplemented with the evaluation of the cerebral hemodynamics, and there are several imaging methods for this purpose, each having advantages and disadvantages. There is currently no approved treatment for the treatment of chronic cerebral hypoperfusion and is therefore important to invest in preventive methods, focusing on reversible risk factors capable of causing it. Finally, combining these existing knowledge on chronic cerebral hypoperfusion, I tried to develop a set of guidelines that can be used by health professionals with the aim of reducing the impact of this disease on society. Despite the information still left to clarify in this area, it is already possible to see that this is an important issue in modern medicine, with prospects of further increase in its importance in the future, being essential in the present to develop strategies for their control.
Description
Keywords
Défices Cognitivos Ligeiros Défices Cognitivos Vasculares Demência Vascular Hipoperfusão Cerebral Crónica Prevenção