Urate oxidation in CSF and blood of patients with inflammatory disorders of the nervous system.

Urate is largely excluded from the brain under non-inflammatory conditions (concentration gradient serum:CSF about 10:1), but increases markedly in Guillain-Barré Syndrome and bacterial meningitis. The oxidation product allantoin is normally not passively distributed between blood and cerebrospinal fluid (gradient 3:1) and increases 5-fold in CSF of patients with meningitis. Patients with multiple sclerosis had normal levels of urate and allantoin in blood and CSF.