Toyoda K, Oita J, Yamaguchi T, Sasaoka A, Ogata H
Department of Medicine, National Cardiovascular Center.
Rinsho Shinkeigaku. 1991 Feb;31(2):197-201.
A patient with unilateral nuclear oculomotor palsy due to midbrain infarction is described. A 46-year-old man was admitted because of difficulty in opening right eye and double vision noticed when he awoke in that morning. On admission, neurological examination revealed total right oculomotor palsy with slight impairment of left upward gaze. There were no other neurologic abnormalities at all. Brain CT and cerebral angiograms were also normal. Magnetic resonance imaging (MRI) performed on the ninth day, however, demonstrated high signal intensity in the right tegmentum of the mesencephalon on T2-weighted images, which was shown more clearly after the administration of Gadolinium-DPTA. He was diagnosed as nuclear third nerve palsy caused by midbrain infarction. The majority of isolated oculomotor nerve palsy has been reported to be caused by extraaxial lesion. When the oculomotor palsy is caused by intraaxial ischemic lesion, it is usually accompanied by other brain stem signs, because abundant nuclei and fibers are present adjacent to the oculomotor nucleus and nerve in the mesencephalon. The present case clarified that such a small infarct disclosed only by MRI can cause isolated oculomotor nerve palsy. It is emphasized that the intraaxial ischemic lesion should be ruled out by using the sophisticated diagnostic aid before making diagnosis of peripheral lesion. This is the first report of the isolated third nerve palsy resulting from mesencephalic ischemic lesion in the Japanese.
本文描述了一名因中脑梗死导致单侧核性动眼神经麻痹的患者。一名46岁男性因晨起时发现右眼睁开困难及复视而入院。入院时，神经系统检查显示右侧完全性动眼神经麻痹，左侧上视略有受损。无其他任何神经系统异常。脑部CT和脑血管造影也均正常。然而，在第九天进行的磁共振成像（MRI）显示，在T2加权图像上中脑右侧被盖区有高信号强度，注射钆喷替酸葡甲胺后显示得更清楚。他被诊断为中脑梗死所致的核性动眼神经麻痹。据报道，大多数孤立性动眼神经麻痹是由轴外病变引起的。当动眼神经麻痹由轴内缺血性病变引起时，通常会伴有其他脑干体征，因为中脑动眼神经核和神经附近有丰富的核团和纤维。本例表明，仅通过MRI发现的如此小的梗死灶可导致孤立性动眼神经麻痹。强调在诊断周围性病变之前，应使用先进的诊断辅助手段排除轴内缺血性病变。这是日本首例关于中脑缺血性病变导致孤立性动眼神经麻痹的报道。
