Ataxie et confusion après traitement par 5-fluorouracile

Association between malignancy and non-alcoholic Wernicke's encephalopathy: a case report and literature review

Background

Wernicke's encephalopathy is a serious medical condition associated with high morbidity and mortality caused by deficiency of thiamine. This disease is classically associated with alcoholism, but is underappreciated in the nonalcoholic population. There is growing acknowledgement of the development of Wernicke's encephalopathy in patients with malignancies.

Methods

We conducted a literature review in PubMed for cases of Wernicke's encephalopathy occurring in patients with malignancy. We also present the case of a 47-year-old woman with recurrent laryngeal cancer and multiple hospital admissions for malnutrition. Neurological examination was notable for pendular nystagmus, severe gait ataxia, confusion, and poor memory consolidation. MRI of the brain was significant for T2-weighted fluid-attenuated inversion recovery hyperintensities in periaqueductal regions, medial thalami, and the tectal plate, typical for Wernicke's encephalopathy. She was treated with thiamine repletion, and had marked improvement in her mental status and some improvement in her vision problems and ataxia, although some nystagmus and significant short-term memory impairment persisted.

Results

The literature review yielded dozens of case reports of Wernicke's encephalopathy in patients with malignancy, dominated by cases of patients with malignancies of the gastrointestinal system, followed by those with hematologic malignancies.

Conclusions

Malignancy is an important risk factor for the development of Wernicke's encephalopathy. This diagnosis is underappreciated and difficult for the clinician to discern from multifactorial delirium. Clinicians should be aware to treat at-risk patients with thiamine immediately, especially if multiple risk factors are present.

5-FU-induced neurotoxicity in cancer patients with profound DPD deficiency syndrome: a report of two cases

PURPOSE

5-Fluorouracil (5-FU) is a mainstay for treating various solid tumours in adults, including digestive and head and neck cancers. 5-FU-related toxicities usually include haematological, digestive and cutaneous features. Additionally, 5-FU has been described as being potentially neurotoxic in patients, but these side effects are quite rare in clinical practice. Here, we report two cases of sudden and unpredictable drug-induced neurotoxicities that occurred in patients undergoing their first course of 5-FU-based chemotherapy.

PATIENTS AND METHODS

None of these patients had any previous neurological disorder history, and both were treated following standard regimen (LV-5-FU2 and TPF for patient 1 and 2, respectively). Neurotoxicity included drowsiness, acute confusion plus dysarthria for the first patient and seizure, confusion and signs of metabolic encephalopathy for the second one. In addition, typical 5-FU-related severe toxicities (e.g. neutropenia and mucosities) were observed. Both patients slowly recovered from these neurological toxicities under supportive treatment. It was assumed that overexposure to 5-FU could explain the severe toxicities encountered. To test this hypothesis, we retrospectively evaluated the dihydropyrimidine dehydrogenase (DPD) activity of these patients on a phenotypic basis.

RESULTS

Evaluation of the uracil-to-di-hydrouracil (U/UH2) ratio in plasma revealed a profound DPD deficiency syndrome in both patients.

CONCLUSION

These cases suggest that 5-FU standard dosage administration may lead to strong overexposure, responsible for the severe toxicities observed, including the neurological features. It implies that DPD deficiency can cause neurotoxicity in 5-FU-treated patients and advocates for the prospective screening of DPD deficiency before starting any 5-FU-containing chemotherapy so as to prevent such side effects in the future.