Measurement of local cerebral glucose utilization before and after V-P shunt in congenital hydrocephalus in rats.

Local cerebral glucose utilization (LCGU) was measured by the [14C]deoxyglucose autoradiographic method in rats with congenital hydrocephalus before and after a V-P shunt. LCGU was decreased throughout the brain in hydrocephalus. The most severely affected regions were found in the cortex, with which a marked degree of subcortical cerebrospinal fluid (CSF) edema was associated; regions in the brain-stem structures were less affected. These metabolic disturbances were improved in many regions after a V-P shunt. However, no improvement was found in the cortex; therefore, damage was considered irreversible. CSF edema was also found in the periaqueductal gray matter in which impaired LCGU was observed; however, this metabolic disturbance was normalized after a V-P shunt. This study suggests that regional differences in the brain seen in hydrocephalus and CSF edema may have varying ill effects on cerebral metabolism. Without prompt treatment, metabolic damage progresses and becomes irreversible. It is suggested that metabolic impairment in the brain stem which is reversible is due mainly to increased intracranial pressure (ICP).