脳溝に沿ったくも膜下出血を再発し脳皮質下出血を来したアミロイド・アンギオパチーの1症例

A Case of Cerebral Amyloid Angiopathy in which a Restricted Subarachnoid Hemorrhage Recurred in the Cortical Sulcus Following a Subcortical Hemorrhage

Ⅰ．はじめに

　脳アミロイド・アンギオパチー（cerebral amyloid angiopathy：CAA）は，高齢者に多く，臨床的には脳皮質下出血を繰り返すことで知られており，時にくも膜下出血（subarachnoid hemorrhage：SAH）や点状出血なども呈する場合がある．しかしながら，この場合のSAHは一般的に脳皮質下出血に引き続いて生じるもの（secondary SAH）と考えられており⁹⁾，脳内出血を伴わずにSAHだけを呈する症例は極めて少ない^1,3,5-8)．

　今回われわれは，明らかな誘因もなく脳溝に沿ったSAHを繰り返し，同部位に脳皮質下出血を来した極めて貴重な症例を経験した．

　Cerebral amyloid angiopathy (CAA) is predominantly recognized in elderly people and repeatedly causes a huge subcortical hemorrhage. Some cases of CAA can cause secondary subarachnoid hemorrhage (SAH),but cases in which it causes primary SAH is very rare. We describe a valuable reference case of a 75-year-old man in whom a restricted SAH recurred in the cortical sulcus following a huge subcortical hemorrhage. He presented with an unknown restricted SAH in the left frontal sulcus twice before neck clipping for a right IC-PC unruptured aneurysm. Postoperative computed tomography (CT) revealed a recurrent SAH in the left frontal lobe,and it spread gradually. T2^* weighted imaging (T2^*WI) revealed subarachnoid hemosiderosis and superficial cortical hemosiderosis in the frontal and parietal lobe. On the 21st postoperative day,he suddenly presented right hemiplegia and a huge subcortical hemorrhage was observed in the left frontal lobe on CT. Emergent removal of the hematoma was performed,but the patient had become bedridden. Pathological diagnosis of CAA was made.

　A recurrent restricted SAH in the frontal sulcus might have been a warning sign of a huge subcortical hemorrhage. In the aging society,a radiological prediction of CAA is very important. Although it is generally thought to be very difficult,T2^*WI may be useful for predicting CAA. When we plan surgery for elderly people,we must always take CAA into consideration.