Optic neuritis induced by 5-fluorouracil chemotherapy: Case report and review of the literature

Abstract

Introduction For over 50 years, 5-Fluorouracil has played a critical role in the treatment of numerous malignancies, including colorectal cancer. Ocular side effects are uncommon and include blurred vision, conjunctivitis, excessive lacrimation and keratitis. Case report We report a 57-year-old male with metastatic colorectal cancer who had received extensive chemotherapy with 5-Fluorouracil-based regimens for over 12 months. Following his seventh cycle of cetuximab/FOLFIRI, he developed acute onset global headache, nausea and loss of vision in the right eye. After detailed investigations, including ophthalmologic and neurologic consultations, a diagnosis of optic neuritis was made. Management and outcome Chemotherapy was ceased immediately, and intravenous methylprednisolone (1 g) daily for five days was commenced. His headache resolved and vision started to improve within 24 h. Three weeks after completion of corticosteroids, constriction of the right visual field had fully resolved. Discussion Atypical optic neuritis is an inflammatory optic neuropathy that can be caused by ischaemia, mechanical compression, nutritional deficiency, toxins and drugs. Drug-induced optic neuritis, while rare, is associated with cytotoxic medications including methotrexate, cisplatin, carboplatin, vincristine and paclitaxel. There have only been five previous case reports implicating 5-Fluorouracil in the development of optic neuropathy. The likelihood of the adverse drug reaction due to 5-Fluorouracil was assessed using the Naranjo algorithm. A score of +7 indicates probable causality. Clinicians should be alert to this potential ocular toxicity in order to initiate prompt cessation of treatment and early ophthalmology referral to prevent visual loss and damage to ocular structures.

COVID-19 Vaccine-Associated Optic Neuropathy: A Systematic Review of 45 Patients

“…However, in the absence of adjuvants in several of the COVID-19 vaccines, this explanation is insufficient [ 19 ]. Clinically, it is challenging to differentiate between AION and optic neuritis, and the diagnosis is usually based on both clinical impression and multimodal imaging findings including neuroimaging [ 77 , 78 , 79 ]. Some differentiating features include older age of onset, altitudinal field defect, and worse visual outcomes in patients with AION, which was also found in our study; however, these features cannot confidently distinguish between both conditions [ 77 ].…”

Optic neuropathy after COVID-19 vaccination: Case report and systematic review

“…However, in the absence of adjuvants in several of the COVID-19 vaccines, this explanation is insufficient ( Elnahry et al, 2021 ). Clinically, it is challenging to differentiate between AION and optic neuritis, and the diagnosis is usually based on both clinical impression and multimodal imaging findings ( Levin, Rizzo and Lessell, 1996 , Elnahry and Elnahry, 2020 , Raina et al, 2020 ). Some differentiating features include an older age of onset, altitudinal visual field defect, and worse visual outcome in patients with AION which was also found in our study, however, these features cannot confidently distinguish between both conditions ( Levin, Rizzo and Lessell, 1996 ).…”

Response to: Optic neuritis induced by 5-fluorouracil chemotherapy: case report and review of the literature

“…We read with great interest a recent article published by Raina et al in your journal regarding the occurrence of 5-fluorouracil associated optic neuropathy in the context of treatment of a case of metastatic colorectal cancer. 1 I too (the first author) have recently reported a similar case of optic neuropathy associated with 5fluorouracil therapy. 2 In the beginning, we would like to congratulate the authors on their diagnosis and management of this difficult case; however, we have several comments regarding their article.…”