遅発性出血を呈した外傷性中硬膜動脈偽性動脈瘤による硬膜外血腫の1例

Delayed Epidural Bleeding Caused by Traumatic Pseudoaneurysm of the Middle Meningeal Artery : Case Report

　Ⅰ．はじめに

　硬膜外血腫は通常，頭蓋骨骨折を伴い中硬膜動脈の断裂による疾患で緊急手術を要する場合がほとんどであるが，時に保存的に経過をみる症例がある⁸⁾．特に外傷性中硬膜動脈偽性動脈瘤の破裂による頭蓋内出血は受傷後数日して発症することがあり¹¹⁾，医療訴訟の観点からも中硬膜動脈偽性動脈瘤の有無の診断は重要である．しかし，最近では硬膜外血腫で脳血管撮影が行われる症例は減少しており，術前に外傷性中硬膜動脈偽性動脈瘤が診断される症例は少なくなっている．われわれは急性硬膜外血腫にて入院し経過観察中硬膜外に遅発性出血を認め，興味ある画像所見を呈した症例を経験したので報告する．

　A 16-year-old man who presented with delayed bleeding of epidural hematoma is reported. Computed tomography (CT) on admission demonstrated a small amount of right epidural hematoma and a small fracture of the right lateral orbital wall. He was treated conservatively. Repeated CT scans and magnetic resonance (MR) imaging revealed no growth in the epidural hematoma,but demonstrated flow void sign at the medial side of the hematoma on MR images. After 8 days,CT scan presented the regrowth of the hematoma,so we planned the removal of hematoma. Epidural hematoma due to the rupture of a traumatic pseudoaneurysm of the middle meningeal artery is rare. Especially,since traumatic lesions were diagnosed by CT,it was unusual to be able to diagnose the pseudoaneurysm of middle meningeal artery preoperatively. The cases of epidural hematoma treated conservatively should be followed up by MR imaging and MR angiography using the fat suppression technique.