軽微な頭部打撲後に硬膜下血腫を来たした脳室腹腔シャント留置患者の2例―硬膜下水腫・血腫を来たした脳室腹腔シャント留置患者の臨床的検討

Subdural Hematoma following Minor Head Trauma in Patients with Ventriculoperitoneal Shunts : Two Case Reports

はじめに

　正常圧水頭症に対する脳室腹腔シャント（以下VPシャント）後の合併症として，髄液過剰排液による硬膜下水腫あるいは血腫が少なからず経験されるが^1），最近では可変式差圧バルブによる圧設定変更にて対処可能となり^2），外科的処置を要する症例は減少してきている^3）．しかしながら今回我々は，歩行訓練中の転倒に伴う軽微な頭部打撲後に硬膜下血腫を生じ，治療に難渋した症例を2例経験した．そこで，これら2症例の臨床的問題点を，当院でのVPシャント留置患者における硬膜下水腫および血腫の臨床的特徴と合わせて検証し，VPシャント留置患者にリハビリテーション（以下，リハ）を行う際の注意点について検討したので報告する．

Abstract : Subdural hematoma or effusion is a common complication in ventriculoperitoneal shunts. However, the incidence of subdural hematoma in shunted patients requiring a surgical procedure has been decreasing recently, since it can be treated with a newly developed pressure-programmable valve system. We treated two shunted patients with subdural hematomas caused by simple falls during gait training. The management was complicated, involving multiple surgical procedures. Case 1 : A 65-year-old woman, who had undergone ventriculoperitoneal shunting for normal pressure hydrocephalus after removal of a meningioma, suffered mild head trauma due to a fall during gait training and developed consciousness disturbance after 2 hours. Computed tomography revealed an acute subdural hematoma with marked midline shift. Emergency craniotomy and hematoma evacuation were performed. Case 2 : A 61-year-old man, who had previously undergone ventriculoperitoneal shunting for normal pressure hydrocephalus after subarachnoid hemorrhage, fell to the floor during gait training. Computed tomography demonstrated a thin subdural hematoma, thus the pressure-programmable valve was adjusted to a higher pressure. However, the hematoma continued to enlarge and his level of consciousness deteriorated. Consequently, shunt ligation and irrigation of the chronic subdural hematoma were performed 6 days after the head trauma. Brain atrophy and a lowering of the intracranial pressure, which are both shunt-related complications, may have contributed to these patient's subdural hematomas forming after such relatively minor head traumas. In conclusion, rehabilitation physicians treating shunted patients must be aware of the possibility of a catastrophic intracranial hemorrhage following minor head trauma and of the various treatment-related difficulties arising in such a scenario including exacerbation of hydrocephalus, meningitis, and rebleeding.