| 特集名 | 脳の機能的・器質的変化 | |
|---|---|---|
| 題名 | 透析患者の脳障害 (2) 脳機能異常(血流・代謝異常) | |
| 発刊年月 | 1997年 02月 | |
| 著者 | 平方 秀樹 | 九州大学医学部腎疾患治療部 |
| 著者 | 石田 伊都子 | 九州大学医学部腎疾患治療部 |
| 【 要旨 】 | 脳機能は脳循環代謝に基づく神経細胞の生命活動によって成り立ち，脳血流量や脳酸素・ブドウ糖代謝率などの脳循環代謝諸量は脳機能を評価する有力な指標である． 透析患者では，脳酸素代謝率が低値で，貧血の程度によらない．この低酸素代謝率が，神経細胞それ自体の機能障害に基づく低代謝を示すのか低血流による二次的な低代謝なのかは明らかでないが，腎移植後には脳機能が改善することから神経細胞の障害が主因と考えられる．また，透析の長期化は脳血流量を低下させる要因である．血液透析後には，除水に伴うヘマトクリットの上昇が血液粘度を上昇させて血流量低下の原因となる．このことは，主幹動脈に狭窄病変を有する例で高度である． 慢性透析療法は，腎機能が廃絶した後の長期の延命を保証し，患者のQOLを障害する合併症の治療法が検討されている．今後は，透析患者の脳機能障害についての検討を進め，脳機能保護を視野に入れた透析療法を確立する必要がある． |
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| Theme | Functional and Organic Changes of Brain Observed in Dialysis Patients | |
|---|---|---|
| Title | Depressed brain oxygen metabolism in chronic hemodialysis patients | |
| Author | Hideki Hirakata | The Kidney Care Unit, Faculty of Medicine, Kyushu University |
| Author | Itsuko Ishida | The Kidney Care Unit, Faculty of Medicine, Kyushu University |
| [ Summary ] | Brain function is based on individual nerve-cell activities which depend on both oxygen and glucose delivered by the blood flow. Measurements of cerebral blood flow and the metabolic rate for either oxygen or glucose are known to be useful indices of brain function. In chronic hemodialysis patients, we found that the depressed cerebral oxygen metabolism irrespective of anemia degree is a characteristic feature and that the patients with a longer hemodialysis duration had significantly lower cerebral blood flow and oxygen metabolism especially in the frontal cortex. Cerebral blood flow has also been found to decrease after a single hemodialysis in association with a significant increase in both hematocrit and blood viscosity. These observations are reported to be more pronounced in the patients who have severe stenosis in main arterial branches, and thus have a higher risk of ischemic cerebral injuries. In Japan, chronic hemodialysis treatment has developed to guarantee a longer survival after the renal death. However, we have encountered the unexpected complications including dialysis-related amyloidosis and brain dysfunction, both of which markedly diminish patient's QOL. In this context, the strategies for brain protection should be investigated to confirm a better QOL. | |