慢性腎透析と脳血管障害

Abstract

Recently, the age of patients receiving chronic hemodialysis has markedly increased and diabetic nephropathy in aged subjects is often induced by dialysis. Consequently, many aspects of the patterns and features of cerebrovascular diseases complicated by dialysis are changing.1. Cerebral hemorrhage in chronic dialysis patients are more frequent and more severer than in non-dialysis subjects or the general population. Subcortical hemorrhage, is more frequently seen in dialytics, the cause of which is unknown. However, in aged persons, amyloid degeneration of the cerebral arteries is common, so cerebral hemorrhage due to amyloid angiopathy must be cautiously checked, although we have no clinical method of detecting amyloid angiopathy in daily practices.The incidence of cerebral hemorrhage in dialytics has decreased in recent years, perhaps due to effective control of hypertension and improvement of dialysis techniques, but the frequency of cerebral infarction may increase again. Pathogenesis of cerebral hemorrhage in dialytics is discussed.2. In a cranial MRI study on 71 dialysis patients without cerebrovascular signs and symptoms, ischemic changes were classified into cerebral white matter lesions, lacunes and brain stem infarctions.a) Ischemic brain changes on MRI were found in 38 subjects (53.5%), but cerebral hemorrhage was found in only 1 patient (1.4%). In the remaining 32 (45.1%), there were no abnormal images. Ischemic lesions on MRI were found more than half of the dialysis subjects and increased with advancing age; above 70 years of age, practically all patients showed ischemic changes on MRI imaging. The frequency of brainstem lesions showed no age-difference. Lacunes were reduced after middle-age, while cerebral white matter lesions increased linearly with advancing age. Although asymptomatic cerebral lesions were found in many of dialysis patients, whether they were really “asymptomatic” or not, is an important issue. Psychiatric evaluations are needed in dialysis patients, because depression or other psychiatric manifestations are not rare in these subjects.3. Six dialysis patients with cerebral hemorrhage or cerebral infarction verified on MRI and/or at autopsy are presented. A 47-year-old male patient with autosomal dominant polycystic kidney disease (PKD) showed a massive cerebral hemorrhage in the putaminal region. Intracranial aneurysms were not found in this patient. Genetic relationship in autosomal dominant PKD is discussed, especially in relation to collagen genes.4. Incidental cerebral aneurysms were found in 88 subjects aged sixty years or more among 1, 200 non-selected routine autopsies. Rupture occurred in 17% of all aneurysms, while fatal ruptures were found in 78% of aneurysms more than 6mm in diameter. MRI imaging is necessary in cases of dialysis to find silent cerebral aneurysms, the rupture of which may often be fatal.5. Subdural hematoma (SDH) are not rare in dialysis patients. We must remain alert to this disorder, because SDH is apt to be misinterpreted in dialysis patients.6. We propose that a liason of therapists including internal medicine, neurology, neurosurgery or orthopedics should be organized for prevention and management of cerebrovascular lesions in chronic dialysis.