Case series: CSF LDH, proteins and electrolyte levels in patients of acute lymphocytic leukemia.

BACKGROUND: Central nervous system (CNS) involvement is common in hemoncologic diseases especially in patients with acute lymphocytic leukemia (ALL). Currently available modalities have limitations in diagnosing CNS involvement in early stages of disease and have a limited prognostic value. Raised cerebrospinal fluid (CSF) total lactate dehydrogenase (LDH) levels can predict CNS involvement in patients with various neurological disorders including CNS leukemia. METHODS: This study was conducted in 23 consecutive freshly diagnosed patients of ALL without any previous CNS disease. Analysis of CSF was done for total LDH, proteins and electrolytes in all the patients before the start of chemotherapy and when the patients were in remission or 6 weeks after chemotherapy whichever was earlier. Twenty-three age and sex matched controls were also studied to set the normal reference range. The results were analyzed statistically by Student's t test and coefficient of co-relation between CSF LDH and protein in patients with raised CSF LDH at the time of presentation was also calculated. RESULTS: CSF LDH was increased in 4 out of 6 patients with signs and symptoms of CNS involvement (Group A) and 3 of these patients also had increased CSF protein levels. 2 out of 17 patients without signs and symptoms of CNS involvement (Group B) had both elevated CSF LDH and protein levels. The increased levels came down to normal reference values after chemotherapy except in one Group A patient in whom CSF LDH remained high. However, no significant change in CSF electrolytes was noted in these patients. CONCLUSION: Raised CSF LDH and CSF protein levels may indicate CNS involvement in patients with ALL.