子癇発作から非脳動脈瘤性くも膜下出血を発症したHELLP症候群の1例

A Case of HELLP Syndrome Resulting in Eclampsia with Non-aneurysmal Subarachnoid Hemorrhage

Ⅰ．はじめに

　周産期出血性脳卒中は4～20人/10万人と報告されている．くも膜下出血（subarachnoid hemorrhage：SAH）もその1つであるが，多くは既存の脳動脈瘤や脳動静脈奇形（arteriovenous malformation：AVM）の破裂によって生じる⁷⁾．なかでも円蓋部に限局するSAH（convexity SAH：cSAH）は非動脈瘤性のものが多く，静脈梗塞，reversible cerebral vasoconstriction syndrome（RCVS），posterior reversible encephalopathy syndrome（PRES），cerebral amyloid angiopathyなど原因はさまざまである．HELLP症候群は，溶血性貧血（Hemolytic anemia），肝逸脱酵素上昇（Elevated Liver enzyme），血小板低下（Low Platelet count）を呈する妊娠後期合併症である．妊娠高血圧腎症の中でも特殊な型と考えられ，高血圧や自己免疫学的機序によって惹起される血管内皮のびまん性障害が原因とされている⁴⁾．稀に頭蓋内合併症を発生し，特に出血性脳卒中はしばしば致命的な転帰となることが報告されている⁶⁾．今回われわれは，妊娠後期にHELLP症候群から子癇発作を発症し，cSAHを合併した1例を経験した．本症例では迅速な対応にて母子ともに良好な経過を辿ったものの，画像検査から子癇発作時にPRESを生じていたことも判明した．このためHELLP症候群による脳血管内皮細胞障害に加えて，子癇により自動調節能が麻痺した脳血管に高い灌流圧が加わりcSAHに至ったものと推察した．本症例の病態について，文献的考察を加えるとともに周産期脳卒中対応の留意点を報告する．

　It is known that hemorrhagic stroke at the perinatal period are caused by specifics conditions like eclampsia as well as by the existing abnormal vessels. We treated a case of HELLP syndrome resulting in eclampsia with non-aneurysmal, convexity subarachnoid hemorrhage. A 34-year-old female, who had been pointed out to have a high level of urinal protein at the 37th week, was seen in the emergency department because of severe headache, vomiting and respiratory discomfort. Her systolic blood pressure was over 190mmHg, and caesarean section was selected. On the way to the operating room, she had a generalized convulsion with loss of consciousness. The delivery was carried out. The CT immediately after the caesarean section revealed faint and localized subarachnoid hemorrhage in the bilateral convexity areas. Additionally, the FLAIR image of MRI demonstrated increased intensity in the bilateral cerebellar hemispheres, basal ganglion and subcortical area, suggesting vasogenic edema. The patient had a good clinical course and the abnormal signal of MRI also recovered by treatment with oral iron and zinc. Here, we report a speculation for the mechanism of this case and precautions against stroke in the perinatal period.