特発性硬膜下血腫の3例

Acute subdural hemorrhage of arterial origin:report of three cases

I．はじめに

　急性硬膜下血腫の多くは，外傷による架橋静脈の破綻や脳挫傷からの出血により形成される．しかし，外傷以外の原因もみられ，脳動脈瘤・脳動静脈奇形・もやもや病などの血管障害や，髄膜腫・転移性脳腫瘍などの腫瘍性の出血が報告されている^5,11,16）．また，明らかな原因疾患なく，皮質動脈よりの出血を生じる急性硬膜下血腫もみられ，急性特発性硬膜下血腫と呼ばれている^15）．

　急性特発性硬膜下血腫の発症の機序や臨床像については未解明な点もある．自験3例に文献的検討をくわえて報告する．

Three cases of acute subdural hematoma without head injury, but associated with bleeding from cortical artery are described.

Case 1: a 74-year-old male had sudden headache during a bronchial asthma attack followed by deteriora-tion of consciousness. He was deeply comatose on admission, and CT scans revealed a huge subdural hematoma. Evacuation of the large hematoma revealeda spurting cortical branch of the middle cerebral artery beneath it.

Case 2: Four days before admission, a 69-year-old male developed headache during a fit of coughing. His CT scans on admission showed a thin subdural hemato-ma. Because it was increasing in volume, the hematoma was removed surgically. A spurting cortical branch of the middle cerebral artery was seen on the surface of the temporal lobe.

Case 3: a 80-year-old male, who had had an opera-tion for inguinal hernia under spinal anesthesia ten days before, suffered a sudden headache just after he stood up. CT scans revealed a thick subdural hemato-ma. As the clot was being removed a spurting artery was seen in the Sylvian region.

In a review of 116 surgical cases of acute subdural hematoma at our institute, the incidence of acute spon-taneous subdural hemorrhage was 2.6%. The etiology of nontraumatic hematoma is a matter of controversy. Our three cases suggested that the etiology might be the rupture of a cortical artery at the site of adhesion with the dura mater. This would predispose the artery to tearing with minor trauma. Hematoma evacuation by craniotomy and treatment of the ruptured cortical artery were necessary for favorable outcome.