Lactic dehydrogenase isoenzyme in cerebrospinal fluid of children with febrile convulsions

Cerebrospinal fluid lactate dehydrogenase isoenzymes in children with bacterial and aseptic meningitis

Differentiation of bacterial from aseptic meningitis may be difficult. Our aim was to determine the pattern of distribution of lactate dehydrogenase (LDH) isoenzymes in the cerebrospinal fluid (CSF) of patients with bacterial and aseptic meningitis. One hundred and fifty-seven patients with suspected meningitis were enrolled in the study. They were divided into 3 groups according to the culture- or bacterial antigen assay-proven diagnosis and CSF findings: bacterial meningitis (n = 31), aseptic meningitis (n = 65), and non-meningitis (n = 61). Total LDH level and percentages of LDH isoenzymes in the CSF were measured in each patient. Each group showed a distinct LDH isoenzyme distribution pattern, with a statistically significant difference among the groups in the percentages of the various isoenzymes. Compared with the non-meningitis group, total LDH activity in the CSF was high in the aseptic meningitis group (49.82+/-35.59 U/L, P < 0.001) and exaggerated in the bacterial meningitis group (944.53+/-112.3 U/L, P < 0.001). Low LDH-2 levels were unique to bacterial meningitis (P < 0.01), whereas high LDH-3 levels were characteristic of aseptic meningitis (P < 0.05). Both groups had low levels of LDH-1 and high levels of LDH-4 and LDH-5. In conclusion, the LDH isoenzyme pattern may be of clinical diagnostic value in meningitis, particularly when culture results are pending.

Lactic dehydrogenase isoenzymes in adolescents with multiple sclerosis

Multiple sclerosis is an immune-mediated demyelinating disease with high morbidity and major mortality. To determine the potential use of lactic dehydrogenase activity and lactic dehydrogenase isoenzyme concentrations in cerebrospinal fluid as biomarkers of multiple sclerosis, we reviewed the files of all patients with multiple sclerosis who attended our tertiary pediatric medical facility from 1999-2005. The study group included three adolescent patients with multiple sclerosis (cerebrospinal fluid analysis at diagnosis) and one patient with recurrent optic neuritis (cerebrospinal fluid analysis during a disease episode). The isoenzyme pattern was abnormal in all patients with multiple sclerosis, with higher-than-normal levels of lactic dehydrogenase-2, lactic dehydrogenase-3, and lactic dehydrogenase-5 in two patients, and lower-than-normal levels of lactic dehydrogenase-4 in one patient. It was not necessarily, however, the same two patients who had the abnormally high levels of lactic dehydrogenase-2, -3, and -5. The patient with optic neuritis also exhibited an abnormal lactic dehydrogenase isoenzyme pattern that shared common features with the others. Multiple sclerosis appears to be characterized by an abnormal lactic dehydrogenase isoenzyme pattern in cerebrospinal fluid. The importance of this finding and its diagnostic potential use warrant further investigation.