[Changes in CSF pressure induced by acetazolamide administration test--as an indicator of shunt operation for so-called normal pressure hydrocephalus].

Lumber subarachnoid pressure was monitored via intrathecally introduced catheter in 9 patients, who showed ventricular dilatation on brain CT and were suspected of normal pressure hydrocephalus. During the pressure measurement, 500 mg of acetazolamide was rapidly injected intravenously and changes of CSF pressure were recorded. The results of the study were compared to clinical signs, brain CT findings and results of continuous pressure monitoring. The types of response of CSF pressure induced by acetazolamide administration were classified into 2 groups. In 5 cases (Group A), more than 50 percent increase of CSF pressure compared to the resting value was noted. On the contrary, in the remaining 4 cases (Group B), CSF pressure showed only slight increase (less than 25 percent or none). VP shunt was performed in 4 cases in Group A. Definite improvement of clinical symptoms was observed in all of these surgically treated cases. Correlation was found between the response to Acetazolamide administration and the appearance of B wave in the continuous spinal pressure monitoring. This study suggests that Acetazolamide test may be useful diagnostic test to select the patients for shunt operation.