[Hyperviscosity syndrome with pseudopapilledema and cerebral ischemia].

Papilloedema and fundal haemorrhages in a 46-year-old man were diagnosed to be due to polycythaemia and resultant abnormal blood viscosity. Viscosity was normalized by isovolemic haemodilution: papilloedema and fundal haemorrhages disappeared. Reduction in blood viscosity up to hyperfluidity increased mean regional cerebral blood flow, particularly in those areas of the brain in which initial blood flow was reduced. The effectiveness of isovolemic haemodilution was demonstrated in the patient by fluorescence angiography for the fundus, and by 133Xenon inhalation for cerebral blood flow.