[Diagnostic value of the CSF uric acid level (author's transl)]

Uric acid is the end-product of purine metabolism, and purines are the nitrogenous bases derived from the breakdown of nucleic acids. The CSF uric acid level is thought to be the index of the turnover of the nucleic acid and the degree of the cellular destruction in the brain. CSF uric acid levels were investigated in normal controls (30 cases) and in patients with brain tumor (20 cases), microcephalus (8 cases) and craniostenosis (4 cases). The mean values and standard deviations of CSF uric acid levels in normal controls were as follows; Newborn--9 yrs 0.34 +/- 0.09 mg/dl; 10 yrs--19 yrs 0.50 +/- 0.18 mg/dl; 20 yrs--29 yrs 0.46 +/- 0.05 mg/dl; 30 yrs--39 yrs 0.35 +/- 0.10 mg/dl; 40 yrs--49 yrs 0.35 +/- 0.23 mg/dl. Thereafter 0.72 +/- 0.21 mg/dl. The increased CSF uric acid levels after the age of 50 is thought to be due to the cellular destruction in the brain. CSF uric acid levels increased in patients with highly malignant brain tumor such as grade 3 or 4 astrocytoma and sarcomatous meningioma, but were normal in patients with grade 2 astrocytoma and meningiomas of meingothelial or fibroblastic type. CSF uric acid levels decreased in patients with microcephalus, but were almost normal in patients with craniostenosis. There is a significant correlation between CSF uric acid levels and the degree of brain atrophy in infants.