Recurrent Reversible Stroke-Like Encephalopathy After 5-Fluorouracil (5-FU) Chemotherapy - A Case Report and Literature Review

Sep 24, 2026

Recurrent, reversible stroke-like encephalopathy developed after high-dose 5-fluorouracil (5-FU) chemotherapy in a 49-year-old man with stage IV colorectal cancer. Severe encephalopathy occurred during the seventh through ninth cycles of a FOLFIRI regimen and was linked to a 46-hour continuous intravenous 5-FU infusion. Symptoms began shortly after infusion and resolved within 24 hours. The case highlights 5-FU-induced hyperammonemic encephalopathy as a rare but serious, potentially recurrent adverse event requiring immediate infusion cessation, supportive fluids, and close monitoring.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages7

Reading Time18 min

AccessFree to download

Background

Case Report

Patient history and prior treatments

Neurologic presentation and course

Conclusions

Keywords

e-ISSN 1941-5923 © Am J Case Rep, 2023; 24: e938437 DOI: 10. 12659/AJCR.938437 Received: 2022.09.20 Accepted: 2023.02.14 Available online: 2023.03.01 Published: 2023.04.04 Authors’ Contribution: Study Design A Data Collection B Statistical Analysis C Data Interpretation D Manuscript Preparation E Literature Search F Funds Collection G ABCDEF 1 ABCD 1 BD 2 BDEF 1,3 Corresponding Author: Financial support: Conflict of interest: Recurrent Reversible Stroke-Like Encephalopathy After 5-Fluorouracil (5-FU) Chemotherapy: A Case Report and Literature Review Kurniawan Agung Yuwono Susanna Hilda Hutajulu Abdul Gofir Dhite Bayu Nugroho 1 Department of Internal Medicine, Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia 2 Department of Neurology, Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia 3 Clinical Epidemiology and Biostatistics Unit, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia Dhite Bayu Nugroho, e-mail: [dhite@ugm.ac.id](dhite@ugm.ac.id)[ ](dhite@ugm.ac.id)None declared None declared Patient: Male, 49-year-old Final Diagnosis: Colorectal cancer Symptoms: Hemiparesis • unconsciousness Clinical Procedure: — Specialty: Oncology Objective: Unusual clinical course Background: Chemotherapy based on 5-fluorouracil (5-FU) is a well-established treatment for solid cancers, including metastatic or advanced colon cancer. Despite its efficacy, 5-FU can cause rare but serious adverse events such as acute neurotoxicity, which presents as symptoms similar to stroke. Case Report: We report the case of a patient who was diagnosed with stage IV colorectal cancer and who underwent chemotherapy with a high dose of 5-FU as part of the FOLFIRI (Folinic Acid, Fluorouracil, Irinotecan) treatment plan. During the seventh, eighth, and ninth cycles of chemotherapy, the patient suffered from severe encephalopathy, and the cause of this condition was determined to the 46-hour continuous intravenous infusion of 5-FU, which was part of the FOLFIRI regimen. Conclusions: 5-FU-induced hyperammonemic encephalopathy is a rare but serious adverse event that requires immediate recognition and treatment. The first step in managing this condition is to halt the 5-FU infusion and provide the patient with high volumes of fluid. Although most cases of 5-FU-induced encephalopathy resolve spontaneously, recurrence is possible if the drug is re-administered to the same patient. Therefore, it is crucial for healthcare providers to closely monitor patients receiving 5-FU chemotherapy and be aware of the signs and symptoms of hyperammonemic encephalopathy. Early intervention can prevent further complications and ensure the best possible outcome for the patient. It is important to note that while 5-FU-induced hyperammonemic encephalopathy is rare, it highlights the importance of closely monitoring patients receiving chemotherapy to identify and treat adverse events promptly. This can help improve patient outcomes and prevent serious long-term complications. Keywords: Colorectal Neoplasms • IFL Protocol • Ischemic Stroke Full-text PDF: [https://www.amjcaserep.com/abstract/index/idArt/938437](https://www.amjcaserep.com/abstract/index/idArt/938437) 1744 3 4 16 Publisher’s note: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher This work is licensed under Creative Common AttributionNonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) e938437-1 Indexed in: [PMC] [PubMed] [Emerging Sources Citation Index (ESCI)][Web of Science by Clarivate] Yuwono [K.A. et](K.A. et

FAQs

What caused the patient’s stroke-like encephalopathy after chemotherapy?

The encephalopathy was attributed to 5-FU-induced hyperammonemic neurotoxicity associated with the 46-hour continuous intravenous 5-FU infusion used in the FOLFIRI regimen.

How was the condition recognized and managed in the report?

Immediate recognition was emphasized; the first management step is to stop the 5-FU infusion and provide high volumes of fluid to support recovery.

Can the encephalopathy recur if 5-FU is re-administered?

Yes. Although many cases resolve spontaneously, recurrence is possible if the same patient receives the drug again, so close monitoring for signs and symptoms is crucial.

Sep 24, 2026

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