[Shunt indication of CSF circulatory disturbance with cerebral atrophy (atypical normal pressure hydrocephalus): evaluation of serum alpha 1-antichymotrypsin and pressure wave on epidural pressure monitoring].

PURPOSE: The purpose of this study was to evaluate serum alpha 1-antichymotrypsin (alpha 1-ACT) and pressure wave on continual epidural pressure (EDP) monitoring as the indices for shunt operations in CSF 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 alpha 1-ACT value (nephelometry method, SRL Co.). Continual measurement of EDP was made preoperatively (Geltec Co.). A comparative assessment was made regarding the preoperative alpha 1-ACT value and appearance or not of pressure wave at EDP in the group whose symptom was improved by shunt (effective group: E) and the other group (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 alpha 1-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 alpha 1-ACT value can be regarded as an index for shunt indication for ANPH, and the value was lower in group E than group NE. The value at the boundary between effectiveness and ineffectiveness 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 alpha 1-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.