Reporting on Adverse Clinical Events

Abstract

A 49-year-old male patient became unconscious during the administration of the seventh cycle of FOLFIRI (Folinic Acid, Fluorouracil, Irinotecan: every 3 weeks for 12 cycles) for the treatment of stage IV sigmoid adenocarcinoma with liver metastases. Concurrent medications included ondasentron and dexamethasone. A neurological examination revealed a normal light pupillary response, weakness in the right limbs, and no meningeal sign or pathological reflex. A brain scan without contrast revealed a subacute infarction in the left capsula externa. The diagnosis was an acute ischemic stroke, which fully resolved with antiplatelet treatment. After completing the eighth cycle of FOLFIRI, the patient was discharged with only mild nausea. However, a few hours after discharge, the patient became unconscious and developed symptoms similar to those that occurred after the seventh cycle. During the ninth cycle, the patient again became unconscious near the end of the 5-fluorouracil (FU) infusion with similar symptoms presenting. Diagnosis was 5-FU-induced encephalopathy which responded to rehydration and laxatives with uneventful recovery and discharge 2 days later. The ammonia level was elevated (152.6 ug/dL). The regimen was switched from 5-FU to capecitabine. The authors concluded that this patient developed hyperammonemic encephalopathy related to 5-FU infusions based on the temporal relationship between the administration of the drug and the appearance and resolution of symptoms. According to the Naranjo’s probability score for adverse drug reactions, there was a probable association between 5-FU administration and encephalopathy.