Downregulation of cerebrospinal fluid production in patients with chronic hydrocephalus

Object. The goal of this study was to determine the effect of hydrocephalus on cerebrospinal fluid (CSF) production rates in patients with acute and chronic hydrocephalus. Methods. The authors studied CSF production both in patients presenting with acute and chronic hydrocephalus, and patients with Parkinson disease (PD) of a similar mean age, whose CSF production was known to be normal. A modification of the Masserman method was used to measure CSF production through a ventricular catheter. The CSF production rates (means ± standard deviations) in the three groups were then compared. The patients with PD had a mean CSF production rate of 0.42 ± 0.13 ml/minute; this value lies within the normal range measured using this technique. Patients with acute hydrocephalus had a similar CSF production rate of 0.4 ± 0.13 ml/minute, whereas patients with chronic hydrocephalus had a significantly decreased mean CSF production rate of 0.25 ± 0.08 ml/minute. Conclusions. The authors postulate that chronic increased intracranial pressure causes downregulation of CSF production.