Tratamento do acidente vascular cerebral agudo

Mohr, J. P.; Oliveira, V.

doi:10.1590/S0004-282X1988000200014

Resumos

Avanços tecnológicos recentes beneficiaram o diagnóstico do acidente vascular cerebral (AVC), reduziram os riscos e aumentaram a freqüência de estudos acerca dos mecanismos do AVC. Projetos baseados em bancos de dados computadorizados trouxeram novas luzes quanto à freqüência de subtipos de AVC e aos riscos de sua progressão e recorrência. Elevada freqüência de AVC devidos a infarto continua sem explicação, apesar de exaustiva investigação laboratorial. Esses infartos de causa não determinada apresentam índices de recorrência quase tão elevados como no embolismo cardiogênico, forçando rápida decisão terapêutica, mesmo na ausência de causa demonstrada para eles. AVC devido a aterosclerose é menos comum do que se acreditava, mas traz consigo maior risco de piora e de recorrência precoce, obrigando a adoção de tratamento precoce na tentativa de evitar sua progressão. Os métodos Doppler duplex e transcraniano de imagem de vasos e fluxo tornaram possível atualmente seguir de modo não invasivo a evolução de estenose ateromatosa, embolismo e recanalização, desenvolvimento de circulação colateral e, ainda, ocorrência de vasospasmo em aneurismas rotos e malformações arteriovenosas. Doença ateromatosa extracraniana pode progredir rapidamente, passando a estenose de discreta a severa, podendo, no entanto, estabilizar-se em qualquer ponto da evolução. O grau de estenose extracraniana não permite pressupor aquele de circulação colateral intracraniana. Recanalização ocorre precocemente no embolismo cerebral. Vasospasmo após hemorragia sub-aracnóidea é comum e, por vezes, severo. Sempre que possível deve ser dada preferência à ressonância magnética, em lugar da tomografia computadorizada, para o diagnóstico de qualquer tipo de AVC. inclusive hemorrágico.

Recent advances in technology have improved stroke diagnosis, reduced the risks and increased the frequency of studies of stroke mechanism. Computer-assisted stroke data bank projects have provided new insights into the frequencies of stroke subtypes and the risks for progression and recurrence. A high frequency of strokes due to infarction remain unexplained despite thorough laboratory investigation. These infarcts of undetermined cause suffer recurrence rates almost as high as cardiogenic embolism, forcing a therapeutic decision even in the absence of a demonstrated cause. Stroke from atherosclerosis is far less common than formerly believed but carries the highest risk of worsening and early recurrence, prompting early treatment to attempt to avoid progression. Duplex and transcranial doppler methods of imaging blood vessels and insonating flow have now made it possible non-invasively to follow the course of atheromatous stenosis, embolism and recanalization, development of collateral flow, and vasospasm in ruptured aneurysms and arteriovenous malformations. Extracranial atheromatous disease may progress rapidly from mild to severe stenosis, stabilize at any point; intracranial collateral is not predicted by the degree of extracranial stenosis. Recanalization of cerebral embolism occurs early. Vasospasm after subarachnoid hemorrhage is common and often severe. Where available, magnetic resonance imaging is preferred to CT scanning for the diagnosis of every form of stroke including hemorrhage.

J. P. Mohr^I; V. Oliveira^II

^ISciarra Professor of Clinical Neurology - The New York Neurological Institute (NYNI), Columbia-Presbyterian Medical Center, New York City

^IIResearch Fellow at NYNI, Interno de Neurologia do Hospital Santa Maria, Lisboa - The New York Neurological Institute (NYNI), Columbia-Presbyterian Medical Center, New York City

RESUMO

Avanços tecnológicos recentes beneficiaram o diagnóstico do acidente vascular cerebral (AVC), reduziram os riscos e aumentaram a freqüência de estudos acerca dos mecanismos do AVC. Projetos baseados em bancos de dados computadorizados trouxeram novas luzes quanto à freqüência de subtipos de AVC e aos riscos de sua progressão e recorrência. Elevada freqüência de AVC devidos a infarto continua sem explicação, apesar de exaustiva investigação laboratorial. Esses infartos de causa não determinada apresentam índices de recorrência quase tão elevados como no embolismo cardiogênico, forçando rápida decisão terapêutica, mesmo na ausência de causa demonstrada para eles. AVC devido a aterosclerose é menos comum do que se acreditava, mas traz consigo maior risco de piora e de recorrência precoce, obrigando a adoção de tratamento precoce na tentativa de evitar sua progressão. Os métodos Doppler duplex e transcraniano de imagem de vasos e fluxo tornaram possível atualmente seguir de modo não invasivo a evolução de estenose ateromatosa, embolismo e recanalização, desenvolvimento de circulação colateral e, ainda, ocorrência de vasospasmo em aneurismas rotos e malformações arteriovenosas. Doença ateromatosa extracraniana pode progredir rapidamente, passando a estenose de discreta a severa, podendo, no entanto, estabilizar-se em qualquer ponto da evolução. O grau de estenose extracraniana não permite pressupor aquele de circulação colateral intracraniana. Recanalização ocorre precocemente no embolismo cerebral. Vasospasmo após hemorragia sub-aracnóidea é comum e, por vezes, severo. Sempre que possível deve ser dada preferência à ressonância magnética, em lugar da tomografia computadorizada, para o diagnóstico de qualquer tipo de AVC. inclusive hemorrágico.

SUMMARY

Recent advances in technology have improved stroke diagnosis, reduced the risks and increased the frequency of studies of stroke mechanism. Computer-assisted stroke data bank projects have provided new insights into the frequencies of stroke subtypes and the risks for progression and recurrence. A high frequency of strokes due to infarction remain unexplained despite thorough laboratory investigation. These infarcts of undetermined cause suffer recurrence rates almost as high as cardiogenic embolism, forcing a therapeutic decision even in the absence of a demonstrated cause. Stroke from atherosclerosis is far less common than formerly believed but carries the highest risk of worsening and early recurrence, prompting early treatment to attempt to avoid progression. Duplex and transcranial doppler methods of imaging blood vessels and insonating flow have now made it possible non-invasively to follow the course of atheromatous stenosis, embolism and recanalization, development of collateral flow, and vasospasm in ruptured aneurysms and arteriovenous malformations. Extracranial atheromatous disease may progress rapidly from mild to severe stenosis, stabilize at any point; intracranial collateral is not predicted by the degree of extracranial stenosis. Recanalization of cerebral embolism occurs early. Vasospasm after subarachnoid hemorrhage is common and often severe. Where available, magnetic resonance imaging is preferred to CT scanning for the diagnosis of every form of stroke including hemorrhage.

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