Uric acid is the end-product of purine metabolism, and the purines are nitrogenous bases derived from the breakdown of nucleic acids. It was reported by the authors that CSF uric acid concentrations were increased in patients with histologically malignant brain tumor or microcephaly of atrophic type, but decreased in patients with microcephaly of hypopastic type.
The purpose of this paper is to find out the diagnostic value of uric acid concentrations in cyst fluids of brain tumor or head injury with cyst formation. Cyst fluid, CSF and serum were investigated for uric acid concentration, lactate dehydrogenase activity and total protein concentration in 13 cases of brain tumor and in 7 cases of head injury.
In cases of brain tumor, comparison of uric acid concentrations and lactate dehydtogenase activities between in cyst fluid and in serum can be a comment to the grade of histological malignancy. The finding of cyst fluid levels higher than the serum levels rase a suspicion of histologically malignant brain tumors such as glioblastoma, etc The finding of cyst fluid levels lower than the serum levels raise a suspicion of histologically benign brain tumors such as astrocytoma, craniopharyngioma, epidermoid cyst, etc.
But lactate dehydrogenase activities in cyst fluids were higher than the serum levels in 2 cases of craniopharyngioma which were histoloically benign. Total protein concentrations in cyst fluids were thought to be of no diagnostic value to decide the grade of histological malignancy.
In cases of head injury, materials are chronic subdural hematoma and encapsulated subdural hygroma. Lactate dehydrogenase activities in cyst fluids were higher than the serum levels in cases of chronic subdural hematoma, and lower than the serum levels in cases of encapsulated subdural hygroma. In cases of chronic subdural hematoma, lactate dehydrogenase in the erythrocytes is thought to come out due to hemolysis, and to show increased activity. On the contrary, uric acid concentrations in cyst fluids were lower than the serum levels in both cases of chronic subdural hematoma and encapsulated subdural hygroma. Because uric acid does not exist in the erythrocyte and is not influenced by hemolysis. This phenomenon prove that uric acid concentrations in cyst fluids of brain tumor is not easily influenced by intracystic hemorrhage compared with lactate dehydrogenase activities in cyst fluids. Total protein concentrations in cyst fluids were higher than the serum levels in 2 cases of chronic subdural hematoma, though total protein concentrations in cyst fluids of brain tumor were lower than the serum levels in all cases.
