術後vitamin K(以下,VK)欠乏性頭蓋内出血をきたしたと考えられた破裂脳動脈瘤によるくも膜下出血(以下,SAH)の2症例を報告した.症例1は48歳女性.動脈瘤クリッピング術後10日目に急性硬膜外血腫,17日目には出血性梗塞を起こした.症例2は39歳男性.動脈瘤クリッピング術後14日目に急性硬膜外血腫を起こした.いずれも凝固系検査よりVK欠乏を疑い,VK_2静注を施行し,まもなく止血,以後再出血はなかった.症例2では急性硬膜外血腫手術中に血中 VKを測定し,VKの著しい低下を確認した.VK欠乏の原因としてSAHおよび手術侵襲によるVK消費亢進,抗生剤長期投与の結果としての腸内細菌叢の抑制によるVK産生の低下が考えられた.重症SAHの患者では汎発性血管内凝固症の準備状態にあり,加えてVK依存性凝固因子の産生低下がみられる.術後出血の原因としてVK欠乏症も念頭にいれておくべきと考えられる.The authors report 2 cases of a postoperative intracranial hemorrhage in treated severe subarachnoid hemorrhage (SAH) patients due to a vitamin K (VK) deficiency. These cases are described below. Case 1 : The patient, a 48-year-old woman, was admitted to our hospital because of an SAH, and a neck clipping was soon performed after admission. On the 10th postoperative day, an epidural hematoma was found, and on the 17th postoperative day, a hemorrhagic infarction occurred. Case 2 : The patient, a 39-year-old man, was admitted to our hospital because of an SAH, and a neck clipping was soon performed after admission. On the 14th postoperative day, an epidural hematoma was detected. The concentration of the serum VK during an evacuation of the hematoma was found to have markedly decreased, and a coagulation examination revealed that a VK deficiency had caused the postoperative hemorrhage. A subsequent adnlinistration of VK resolved the hemorrhagic complications in both patients. The VK deficiency in these cases may have been caused by an increased VK consumption due to the pre-DIC state after the SAH and the invasive surgery, and the supression of VK production by intestinal flora because of long-term antibiotic medication. It thus has been speculated that in severe SAH patients, a VK deficiency may be the cause of a postoperative hemorrhagic complication
