[Cerebrospinal fluid edema occurred in normal pressure hydrocephalic patients with functioning ventriculo-peritoneal shunts: report of three cases].

We describe three cases of cerebrospinal fluid edema (CFE) which occurred in hydrocephalic adult patients who underwent ventriculo-peritoneal shunt operations. After shunt operations, the shunt systems were functioning well and symptoms due to hydrocephalus were resolved. However, computed tomographic scans demonstrated CFE around the ventricular catheters in all patients. The patients were free from symptoms due to CFE and observed conservatively. The one-way valve mechanism is thought to be a possible mechanism of CFE in these cases. Although CFE is a very rare complication to occur after shunt operations, it is necessary to follow up the patients even if the shunt is functioning well.