脳萎縮を伴う髄液循環障害（非定型正常圧水頭症）に対するShunt手術適応—血清α1—antichymotrypsin値と硬膜外圧持続測定での圧波の評価

Shunt Indication of CSF Circulatory Disturbance with Cerebral Atrophy (Atypical Normal Pressure Hydrocephalus)—Evaluation of serum α1-antichymotrypsin and pressure wave on epidural pressure monitoring

I．はじめに

　近年，わが国では平均寿命の高齢化が進み“老人ボケ”あるいは“痴呆”が深刻な社会問題となっている．とくに，これらの痴呆患者の中でCT上，高度の脳萎縮を伴う脳室拡大を認める例では，従来は単なる脳の老化としてとらえられていた．また，これらの変化に髄液循環障害を認める例においてもshunt手術の適応外と考えられ，対症的な治療のみが行われていた^9,22,35）．しかし，最近このような症例でもshunt手術が有効であった例3^16,30）が報告されるようになり，その病態が注目されている6）．今回著者らは，脳萎縮を伴う髄液循環障害の患者の中で，Fisher Rating Scale 3徴候^4）の1つ以上を有し，その直接原因が特定できないものを非定型正常圧水頭症（atypical normal pressure hydrocephalus：ANPH）と定義して，とくに血清α₁—anticymotrypsin（α₁-ACT）と硬膜外圧（epidural press ure：EDP）持続測定での圧波出現がANPHのshunt手術適応の因子として評価できるか否かを検討した．

Purpose: The purpose of this study was to evaluate serum a rantichymotrypsin (α₁-ACT) and pressure wave on continual epidural pressure (EDP) monitoring as the indices for shunt operations in CS1 circulatory disturbance associated with cerebral atrophy (atypical normal pressure hydrocephalus : ANPH).

Method: The subjects adopted were 10 patients (aged 48-79, averaging 64.9, male : female = 8.2). V - P shunt was performed on all the cases, and venous blood was collected from the internal jugular vein before and after the operation to measure serum a r ACT value (nephelometry method, SRI. Co.). Continual measure-ment of EDP was made preoperatively (Geltec Co.). A comparative assessment was made regarding the preop-erative a rACT value and appearance or not of pres-sure wave at EDP in the group whose symptom was im-proved by shunt (effective group : E) and the othergroup (non-effective group : NE). Results:① The cases were 6 in group E and 4 in group NE.② The mean values of the preoperative α₁-ACT were 43.47±8.08mg/dl in group E and 63.68 ±5.48mg/dl in group NE. The former exhibited evidently low values, and all the cases whose values were less than 55mg/dl belonged to group E (p＜ 0.001).③ Pressure wave (A or B wave) at EDP were observed in 5 cases, all in group E. Conclusion : ① Serum α₁-ACT value can be regarded as an index for shunt indication for ANPH, and thevalue was lower in group E than group NE. The value at the boundary between effectiveness and ineffective-ness was 55 mg/dl. ② Appearance of pressure wave at measurement of EDP was observed in all of group E. ③ Shunt operation should be taken into consideration for ANPH patients whose preoperative serum α₁-ACT value is low (less than 55mg/dl) and in whom pressure wave emerges at continual measurement of EDP, even though their cerebral atrophy is found to be severe by CT.