5-Fluorouracil-Induced Leukoencephalopathy: Report of Two Cases and Review of Literature

5-fluorouracil (5FU) forms an important component of chemotherapy regimens used in various gastrointestinal (GI) adenocarcinomas and head and neck squamous cell carcinomas. Leukoencephalopathy is a rare adverse effect of 5FU, mediated by hyperammonemia and hyperlactatemia. We report cases of two patients with GI adenocarcinomas who developed neurological symptoms while on 5FU infusion. The neuroimaging and biochemical parameters were suggestive of toxic leukoencephalopathy. They were managed with cessation of the drug and short-term antiepileptic therapy. We also discuss the pathophysiology of this adverse effect and its management.