Cerebrospinal fluid lactate dehydrogenase activities in patients with central nervous system metastases.

Lactate dehydrogenase activities were determined in CSF from 350 patients suffering from various neurological diseases. Reference values were established as 0-26 U/l. Slight elevations of CSF LDH activities were observed in patients with the following disorders: brain metastasis and spinal epidural metastasis from solid carcinomas, primary central nervous system tumours, cerebrovascular accident, polyneuropathy and head injury. Marked elevations were observed incidentally in patients in these groups and in a considerable number of patients with bacterial meningitis and with leptomeningeal spread from solid or haematologic malignancies. When other diagnostic information is available for the proper estimation of the pre-test likelihood of disease, CSF LDH activities exceeding 50 U/l are suggestive for meningeal carcinomatosis.