EEG-changes during intensified induction-therapy of acute lymphoblastic leukemia

In 49 children with acute lymphoblastic leukemia serial EEGs were performed during the course of treatment. Therapy in the first four weeks consisted of: Prednisone, vincristine, daunorubicine and L-asparaginase. In the second month 6-mercaptopurine, cytosin-arabinoside, cyclophosphamide, methotrexate-i. th. and cranial irradiation were administered. Maintenance-therapy consisted of 6-mercaptopurine, cyclophosphamide and methotrexate i.v. Before treatment only 24% of patients showed normal EEG-findings, whereas 57% presented sly induced by leukemic infiltrations and partly due to the impaired clinical state. At the end of the first phase of therapy, the combined toxicity of vincristine and L-asparaginase led to the finding of 23% severely and 37% moderately slowed EEGs. Slightly disturbed EEGs were found in 29% and normal ones in 11% of children. Regression occurred duirng the phase of CNS-prophylaxis. At its end 37% of recordings were normal and 57% slightly abnormal. After maintenance-therapy of 1/2 to 1 year duration, there were 65% normal findings. Moderate and severe disorders were no longer demonstrated. Paroxysmal activity developed twice, each during the first phase of therapy and accompnaying convulsions. In both cases we saw slowing of background-activity and signs of increased excitability still months after. In one of these patients, the probable cause was a vincristin-encephalopathy, the cause of the second case remained unknown. EEGs of two furtehr patients with rubella-encephalitis and subarachnoideal hemorrhage exhibited severe unspecific changes.