Hyperammonemia-induced impaired consciousness following mFOLFOX6 therapy in a patient with recurrent rectal cancer.

Objectives: FOLFOX is a standard chemotherapy regimen used to treat colorectal cancer. Adverse events associated with FOLFOX treatment include peripheral neuropathy and myelosuppression. This report discusses the case of a 64-year-old man with rectal cancer who developed hyperammonemia and impaired consciousness following initiation of mFOLFOX6 as a postoperative adjuvant therapy.
Methods: This case study reports on the clinical disease progression of the aforementioned patient.
Results: Following preoperative chemoradiotherapy, the patient underwent low anterior resection for rectal cancer. mFOLFOX6 was then initiated as postoperative adjuvant therapy. During the 5 ^th cycle of mFOLFOX6 treatment, the patient presented with impaired consciousness and upper extremity convulsions. Blood testing revealed marked hyperammonemia (349 µg/dL (normal range: 12 - 66 µg/dL)). Imaging did not reveal any intracranial lesions that could cause impaired consciousness. The patient recovered within a day after rehydration and BCAA substitution.
Conclusion: Although impaired consciousness is a rare adverse reaction of FOLFOX, it has a major psychological impact on the patient and his/her family. Hyperammonemia should therefore be considered a potential cause of impaired consciousness during FOLFOX therapy and should be appropriately diagnosed and treated.