[A Case of Consciousness Disorder Due to Hyperammonemia Induced by Modified FOLFOX6 for Multiple Liver Metastasis from Rectal Cancer].

A 74-year-old man underwent laparoscopic-assisted high anterior resection with D3 lymph node dissection for rectal cancer, which was simultaneously accompanied by multiple liver metastases. The patient received mFOLFOX6 therapy for liver metastases 1 month after the surgery. Anorexia, nausea, and vomiting appeared on the second day of treatment. On the third day of treatment, impaired consciousness(JCS Ⅱ-20)and flapping tremors appeared. Blood tests revealed hyperammonemia, and the patient was diagnosed with impaired consciousness due to hyperammonemia, which was inferred to be caused by 5-fluorouracil(5-FU). Intravenous infusion and branched-chain amino acids were administered, and the patient recovered. The underlying disease of renal dysfunction, constipation, and dehydration due to chemotherapy might have induced the hyperammonemia. It is important to note that hyperammonemia can lead to a disturbance of consciousness during chemotherapy including 5-FU.