Increased hypoxanthine concentrations in cerebrospinal fluid of infants with hydrocephalus.

Hypoxanthine, the end product of purine metabolism, is usually very elevated in body fluids during severe hypoxia. We measured hypoxanthine in the cerebrospinal fluid of hydrocephalic preterm infants (12 with posthemorrhagic, one with congenital hydrocephalus) to determine whether hydrocephalus is associated with anaerobic metabolism of brain tissue. Cerebrospinal fluid hypoxanthine was undetectable in normal infants. In hydrocephalic infants, the concentration of hypoxanthine ranged from 7.5 mumol/L to 28 mumol (means = 14.3 mumol/L). The hypoxanthine concentrations fell from a mean of 12.8 mumol/L to a mean of 2.0 mumol/L (P less than 0.05) with successful treatment of the ventriculomegaly by lumbar puncture or by ventriculoperitoneal shunt. Patients with acute posthemorrhagic hydrocephalus had similar concentrations of hypoxanthine (means = 14.5 mumol/L) as patients with late or with congenital hydrocephalus (means = 13.8 mumol/L), indicating that brain hypoxia is probably a consequence of the ventriculomegaly and not of the hemorrhagic insult.