Cerebral hypoxia after hyperventilation causes "re-build-up" phenomenon and TIA in childhood moyamoya disease. A near-infrared spectroscopy study.

Near-infrared spectroscopy was used to monitor the sequential changes in the cerebral oxygenation state during and after hyperventilation in two children with moyamoya disease. Hyperventilation induced the build-up phenomenon and a decrease in the concentration of oxy-hemoglobin ([oxy-Hb]) and total hemoglobin ([t-Hb]). The termination of hyperventilation was followed by partial recovery of [oxy-Hb] and [t-Hb]. Subsequently, however, [oxy-Hb] and [t-Hb] decreased again and cytochrome oxidase was reduced. These impairments of the cerebral hemodynamics and oxygen metabolism were closely associated with the re-build-up phenomenon on EEG and with transient ischemic attacks (TIA). The present study implies that cerebral hypoxia after hyperventilation is closely related to the re-build-up phenomenon and ischemic attacks in children with moyamoya disease.