5-Fluorouracil-induced Reversible Encephalopathy.

The management of altered mental status in patients with metastatic cancer is a complex task because of various potential causes such as electrolyte imbalances, brain metastasis, cancer treatments and delirium. Anti-cancer drugs such as methotrexate and cisplatin can cause delirium, and it is crucial to recognise and manage these cases early because of the associated increased morbidity and mortality. This case report presents a rare hyperammonaemic encephalopathy induced by 5-fluorouracil (5FU), a pyrimidine uracil analogue used in gastrointestinal cancers. A 60-year-old woman with metastatic pancreatic adenocarcinoma experienced altered sensorium, incoherent speech and ataxia after chemotherapy, including high-dose 5FU infusion. Her symptoms, along with the exclusion of other common causes, led to a diagnosis of 5FU-induced encephalopathy. Palliative care, supportive care and specific treatments resulted in symptom reversal and discharge with improved functional status. This report emphasises the importance of recognising 5FU-induced encephalopathy for its timely and effective management in clinical practice.