Evidence for Choroid-Plexus Arsorption in Hydrocephalus

Radioiodinated (131ǀ,nl) serum albumin was injected into the lateral ventricles of eight hydrocephalic children, and the changes in isotope concentration in ventricular fluid, blood and urine were sequentially determined over an interval of 72 to 96 hours. Bilateral excisions of the choroid plexus were eventually performed on seven of these patients, and the findings before and after surgery were compared. In severe progressive hydrocephalus, a substantial transventricular absorption of albumin occurred hourly into blood, with eventual extraction in urine. At operation (72 to 96 hours after intraventricular injection), appreciable concentrations of the isotope were present in the choroid plexus and brain parenchyma; after removal of the choroid plexus, the rate of change of intraventricular isotope concentration showed a substantial decrease (average of 48 per cent) and the blood and urine concentrations were similarly reduced. All patients remained hydrocephalice after operation, and in most cases, ventricular enlargement progressed. These data suggest that, in hydrocephalus at least, the choroid plexus may have a substantial absorptive role.