くも膜下出血に，外傷性急性硬膜下血腫を合併した1例

A Case of Subarachnoid Hemorrhage with Acute Subdural Hematoma due to Head Injury:Case report

I．はじめに

　脳血管障害の発症時に意識障害を生じ，その際に頭部外傷を合併することは珍しくない．その場合，CT像では脳血管障害による血腫と外傷性頭蓋内血腫の鑑別が困難なことがある^2,9,12）．脳血管障害発症時に頭部外傷を合併した場合，外傷性頭蓋内損傷が予後に影響する可能性は高く，原疾患と合わせて十分な注意が必要である^10）．今回われわれは，脳動脈瘤破裂によるくも膜下出血発症時に頭部外傷を二次的に合併したと考えられる1例を経験したが，術前には脳動脈瘤の存在にとらわれ，単純な頭部外傷の所見を見逃していた．日常の救急診療の場で注意せねばならないことと考え症例報告する．

Acute intracranial hemorrhages can be caused by cerebrovascular disease or head injury. Diagnostic im-aging is in both cases sometimes similar, so it is diffi-cult to make an exact diagnosis. We report a case of acute subdural hematoma due to head injury after loss of consiousness due to an aneurysmal rupture.

A 52-year-old male was found out fallen on the floor in a state of unconsciousness and was brought to the nearest hospital. CT scan showed subarachnoid hemor-rhage with left acute subdural hematoma and he was transported to our hospital. Angiography revealed a left MCA aneurysm. The next day, a clipping operation was performed but brain contusion was observed in the left frontal lobe. Postoperative CT scan showed con-tusional hematoma at the left frontal lobe and plain skull X-ray films demonstrated a diastatic fracture of the right lambdoid suture.

Acute subdural hematoma due to the rupture of a cerebral aneurysm is sometimes recognized, but the first CT findings are similar to those observed after head injury. When the clinical course of onset is un-clear, we must keep in mind that the cause of acute subdural hematoma may be head injury, even if angiography demonstrates abnormal vessels.