Methods: A search of electronic medical records of children aged 18 years or less, using codes for leukemia and epilepsy, yielded 34 patients. From these, 10 patients with refractory epilepsy were identified.  Medical records were reviewed for details of cancer diagnosis, modalities of, epilepsy phenotype, brain MRI findings, and treatment.  

Results: Of 10 patients with refractory epilepsy, 8 had acute lymphoblastic leukemia and 2 had acute myeloid leukemia. Five children developed epilepsy after achieving remission of leukemia. Six had features of epileptic encephalopathy, and 4 had focal epilepsy.  Five of 6 children with epileptic encephalopathy had features of Lennox-Gastaut-syndrome and one had epileptic West syndrome. Brain MRI of 2 patients with epileptic encephalopathy had structural abnormalities - considered to be causative for epilepsy; other 4 had no overt structural abnormalities. Three of the 4 patients with focal epilepsy had temporal lobe epilepsy, with features of mesial temporal sclerosis; localization was uncertain in the other child. All 10 patients except one in the focal group had received intrathecal chemotherapy; 2 patients had received brain and spine radiation. Seizures were poorly controlled despite multiple AED and other treatments in the epileptic encephalopathy group; 3 with LGS underwent a corpus callosotomy. Two patients with temporal lobe epilepsy had temporal lobectomy with complete seizure freedom in one, major reduction in another. 

Conclusion:  Children with childhood leukemia are at risk for developing epilepsy, even after remission of leukemia. Two phenotypes- focal epilepsy, and epileptic encephalopathy were observed. CNS involvement of leukemia and or its treatment could be causal in development of epilepsy.