Diagnostic significance and source of lactate dehydrogenase and its isoenzymes in cerebrospinal fluid of children with a variety of neurological disorders.

Two hundred and thirty-four cerebrospinal fluid (CSF) specimens from 183 different children were analysed for total lactate dehydrogenase (LD) activity and LD isoenzyme distribution. The LD activities were elevated in the CSF of patients with meningitis, especially with bacterial infections, and with central nervous system (CNS) leukaemia. The CSF LD isoenzyme patterns of both groups generally reflected the number and distribution of lymphocytes and granulocytes in the CSF. Increases in CSF LD levels also occurred in patients with other neurological disorders, such as hydrocephalus, raised intracranial pressure, and epileptic seizures. However, no significant increases in CSF LD activity nor abnormality of the isoenzyme distribution were noted in children who had had a non-specific febrile convulsion.