Aqueductal Stenosis with High Protein Concentration in Ventricular Fluid

　An unusual case of congenital hydrocephalus due to aqueductal stenosis is reported. The patient was 27 day-old male baby when he was admitted in our clinic, with abnormally large head. Although he showed no neurological signs, enormously large cerebral ventricle was demonstrated by pneumoventriculography. The first attempt of ventriculo-atrial shunt was effective only a short period because of obstruction of the ventricular catheter due to unusually high concentration of protein, in fact over 2 gm/dl, in ventricular fluid. Dilution of the ventricular fluid was attempted with successful results at the time of revision of the shunt. The patient was well growing until he died from pneumonia 8 months after discharge. Autopsy revealed a remarkably dilated ventricle forming a single cavity without differentiation of the lateral and third ventricles, and complete absence of the choroid plexus except for in the fourth ventricle. Occlusion of the aqueduct of Sylvius by septum formation was the main cause of internal hydrocephalus. Histological study demonstrated the destroyed ependyma over the ventricular cavity. Regarding as the origin of such a high level of protein concentration in ventricular fluid, it is likely that abnormal vascular permeability to protein may exist in the barrier mechanism. We would emphasize that the dilution technique is an effective method when ventriculo-atrial shunt is required in existence of abnormally high concentration of protein in ventricular fluid.