後頭蓋窩急性硬膜下血腫を伴った特発性血小板減少性紫斑病の1例

A Case of Acute Subdural Hematoma in the Posterior Fossa with Idiopathic Thrombocytopenic Purpura

　特発性血小板減少性紫斑病が原因で発症したと考えられる後頭蓋窩急性硬膜下血腫の1症例を報告する。突然の頭痛と鼻出血を訴え入院した72歳男性で，CTにて後頭蓋窩急性硬膜下血腫を認め，入院時臨床検査データにて血小板数の著明な減少（1,000／mm³）と，出血時間の延長（14分—デューク法）を認め，抗血小板抗体の存在から特発性血小板減少性紫斑病と診断された。症状は軽微で経過観察にて消失した。また，血小板減少症に対しては副腎皮質ホルモンの投与により血液検査所見の改善が得られた。これまでに，特発性血小板減少性紫斑病の中枢神経系合併症として文献的に報告されている症例の多くは，脳内出血であり，急性硬膜下血腫をきたした症例は稀であり報告した。

Intracranial bleeding is one of fatal complications in idiopathic thrombocytopenic purpura although its reported incidence is low. A case of spontaneous acute subdural hematoma complicated with idiopathic thrombocytopenic purpura was reported. He was hospitalized complaining of sudden onset of headache and nasal bleeding without neurological deficit. CT scan revealed subdural hematoma in the posterior fossa especially below the tentorium cere-belli. Further hematological examination proved very low platelet count (1,000/mm³) and anti-platelet antibody in confirmation of a diagnosis of idiopathic thrombocytopenic purpura. As his neur-ological status was good, he was treated medically. His symptoms and platelet count improved gradu-ally with corticosteroid therapy.

Reviewing the literature, acute subdural hematoma with idiopathic thrombocytopenic pur-pura was quite rare and only three cases reported.