5-Fluorouracil-induced hyperammonaemic encephalopathy: A French national survey

Real-life prognosis of neurological complications of botulinum toxin: A nationwide pharmacovigilance study of adverse drug reactions reported in France between 1994 and 2020

BACKGROUND

Botulinum toxin is commonly used in the treatment of neurological disorders. Although neurological complications predominate and can lead to respiratory failure or death, no observational studies have specifically described their clinical features or prognoses.

OBJECTIVES

To characterise real-life clinical features and prognoses of botulinum toxin-related neurological complications.

METHODS

Observational, retrospective, nationwide pharmacovigilance study of all neurological adverse drug reactions (ADRs) related to the use of botulinum toxin in France for neurological indications between 1994 and 2020. The characteristics of neurological complications were collected.

RESULTS

In total, 141 people with systemic neurologic complications (ie, distant from the injection site) and 50 with local complications were included. Median (IQR) age was 53 (36; 66) years, and 107 (56 %) were women. The estimated incidence range (min-max) was 25 - 413 neurologic ADRs per 100 000 injection sessions for neurological indications. Except for 3 miscellaneous cases, all presented symptoms within the clinical spectrum of botulism, either as an isolated symptom (41 %) or as multiple symptoms (59 %), with a time to onset of 12 (7; 15) days after injection and a duration of 54 (28; 90) days. A total of 87 % of cases recovered spontaneously or were recovering on the date of the notification. Drug types were not different between cases with systemic or local ADRs, although the doses were higher in cases with systemic ADRs (P < 0.001). Serious cases were more frequent for systemic ADRs (67 % versus 34 %; P < 0.001). Three complications resulted in death, all after treatment for cervical dystonia or sialorrhea.

CONCLUSION

In this pharmacovigilance study, the outcomes of botulism spectrum symptoms occurring after a botulinum toxin injection for a neurological indication were mostly favourable, although symptoms were often initially serious.

The diagnosis and treatment of disorders of nucleic acid/nucleotide metabolism associated with epilepsy

Epilepsy is a prevalent paroxysmal disorder in the field of neurology. Among the six etiologies of epilepsy, metabolic causes are relatively uncommon in clinical practice. Metabolic disorders encompass amino acid metabolism disorders, organic acid metabolism disorders, and other related conditions. Seizures resulting from nucleic acid/nucleotide metabolism disorders are even more infrequent. This review provides an overview of several studies on nucleic acid/nucleotide metabolism disorders associated with epilepsy, including adenosine succinate lyase deficiency, Lesch-Nyhan syndrome, and aminoimidazole carboxamide ribonucleotide transformylase/inosine monophosphate cyclohydrolase (ATIC) deficiency, among others. The potential pathogenesis, phenotypic features, diagnostic pathways, and therapeutic approaches of these diseases are discussed in this review. The goal is to help clinicians make an accurate diagnosis when encountering rare nucleic acid/nucleotide metabolism disorders with multi-system symptoms and manifestations of epilepsy.

A Case of 5-Fluorouracil-Induced Hyperammonemia and Lactic Acidosis Successfully Treated With Continuous Hemodiafiltration Dialysis

A 51-year-old male patient with stage IVc upper rectal cancer received treatment with aflibercept beta and folinic acid, fluorouracil, and irinotecan. Two days following treatment, he presented with an altered mental status. Head computed tomography showed no abnormalities, but blood tests revealed hyperammonemia and lactic acidosis. As these findings were thought to be side effects of 5-fluorouracil (5-FU), the patient underwent continuous hemodiafiltration. Subsequent to this intervention, the hyperammonemia, lactic acidosis, and impaired consciousness improved, and the patient was discharged on hospitalization day 10. In cases of impaired consciousness during 5-FU administration, in addition to the usual evaluation of the cause of impaired consciousness, ammonia and lactate levels should be measured, and branched-chain amino acids should be administered if impaired consciousness due to hyperammonemia is strongly suspected, and the patient's general condition is stable. If the disturbance of consciousness is prolonged or the patient's general condition becomes unstable, it is advisable to consider initiating blood purification. Additionally, patients with lactic acidosis or unstable general conditions should be considered for blood purification using continuous hemodiafiltration. Therapeutic interventions may lead to neurological improvement even in severe cases, highlighting the importance of prompt and targeted management approaches.

5-Fluorouracil-induced acute leukoencephalopathy: Case report and literature review

Toxic leukoencephalopathy (TL) refers to damage to the brain white matter following exposure to toxic agents. Multiple agents are incriminated in this condition, including chemotherapy drugs. 5-Fluorouracil, widely used in oncology, is responsible for neurotoxicity in less than 5% of cases. We report the case of a 54-year-old male patient who presented with neurological symptoms following 5-FU-based chemotherapy for gastric adenocarcinoma, and whose MRI scan revealed signs suggestive of toxic leukoencephalopathy. We also report on the evolution of the abnormalities described on his MRI after 1 year.

Fluoropyrimidine usage in cases with hyperammonemia: real-world data study using the Japanese Adverse Drug Event Report (JADER) database

PURPOSE

Fluoropyrimidines are anticancer drugs and can cause hyperammonemia both intravenously and orally. Renal dysfunction may interact with fluoropyrimidine to cause hyperammonemia. We performed quantitative analyses of hyperammonemia using a spontaneous report database to examine the frequency of intravenously and orally administered fluoropyrimidine, the reported frequency of fluoropyrimidine-related regimens, and fluoropyrimidine's interactions with chronic kidney disease (CKD).

METHODS

This study used data collected between April 2004 and March 2020 from the Japanese Adverse Drug Event Report database. The reporting odds ratio (ROR) of hyperammonemia was calculated for each fluoropyrimidine drug and was adjusted for age and sex. Heatmaps depicting the use of anticancer agents in patients with hyperammonemia were drawn. The interactions between CKD and the fluoropyrimidines were also calculated. These analyses were performed using multiple logistic regression.

RESULTS

Hyperammonemia was observed in 861 of the 641,736 adverse events reports. Fluorouracil was the most frequent drug associated with hyperammonemia (389 cases). The ROR of hyperammonemia was 32.5 (95% CI 28.3-37.2) for intravenously administered fluorouracil, 4.7 (95% CI 3.3-6.6) for orally administered capecitabine, 1.9 (95% CI 0.87-4.3) for tegafur/uracil, and 2.2 (95% CI 1.5-3.2) for orally administered tegafur/gimeracil/oteracil. Calcium levofolinate, oxaliplatin, bevacizumab, and irinotecan were the most frequently reported agents in cases of hyperammonemia with intravenously administered fluorouracil. The coefficient of the interaction term between CKD and fluoropyrimidines was 1.12 (95% CI 1.09-1.16).

CONCLUSION

Hyperammonemia cases were more likely to be reported with intravenous fluorouracil than orally administered fluoropyrimidines. Fluoropyrimidines might interact with CKD in hyperammonemia cases.

Drug-induced hyperammonaemia

Hyperammonaemia (HA) as a consequence of numerous primary or secondary causes, gives rise to clinical manifestations due to its toxic effects on the brain. The neurological consequences broadly reflect the ammonia level, duration and age, with paediatric patients being more susceptible. Drug-induced HA may arise due to either decreased ammonia elimination or increased production. This is associated most frequently with use of valproate and presents a dilemma between ongoing therapeutic need, toxicity and the possibility of an alternative cause. As there is no specific test for drug-induced HA, prompt discussion with a metabolic physician is recommended, as the neurotoxic effects are time-dependent. Specific guidelines for managing drug-induced HA have yet to be published and hence the treatment approach outlined in this review reflects that outlined in relevant urea cycle disorder guidelines.

A Case of Acute Encephalopathy After the Initiation of FOLFOX Chemotherapy in a Patient With Colon Cancer

Acute encephalopathy is a change in the level of consciousness where the underlying etiology can be difficult to diagnose, and thus, difficult to treat, especially in the context of multi-organ diseases. We report a case of acute encephalopathy in a patient with end-stage renal disease (ESRD) on hemodialysis, chronic hypotension, and a recent diagnosis of colon cancer who presented shortly after initiation of FOLFOX, a chemotherapy regimen for treatment of colorectal cancer comprised of folinic acid (leucovorin), fluorouracil (5-FU), and oxaliplatin (eloxatin). We present a systematic approach to elucidate ambiguous causes of toxic-metabolic encephalopathy.

Drug-associated hyperammonaemia: a Bayesian analysis of the WHO Pharmacovigilance Database

Background

Hyperammonaemia is frequent in Intensive Care Unit patients. Some drugs have been described as associated with this condition, but there are no large-scale studies investigating this topic and most descriptions only consist of case-reports.

Methods

We performed a disproportionality analysis using VigiBase, the World Health Organization Pharmacovigilance Database, using the information component (IC). The IC compares observed and expected values to find associations between drugs and hyperammonaemia using disproportionate Bayesian reporting. An IC_0.25 (lower end of the IC 95% credibility interval) > 0 is considered statistically significant. The main demographic and clinical features, confounding factors, and severity of cases have been recorded.

Results

We identified 71 drugs with a disproportionate reporting in 2924 cases of hyperammonaemia. Most of the suspected drugs could be categorised into 4 main therapeutic classes: oncologic drugs, anti-epileptic drugs, immunosuppressants and psychiatric drugs. The drugs most frequently involved were valproic acid, fluorouracil, topiramate, oxaliplatin and asparaginase. In addition to these molecules known to be responsible for hyperammonaemia, our study reported 60 drugs not previously identified as responsible for hyperammonaemia. These include recently marketed molecules including anti-epileptics such as cannabidiol, immunosuppressants such as basiliximab, and anti-angiogenics agents such as tyrosine kinase inhibitors (sunitinib, sorafenib, regorafenib, lenvatinib) and monoclonal antibodies (bevacizumab, ramucirumab). The severity of cases varies depending on the drug class involved and high mortality rates are present when hyperammonaemia occurs in patients receiving immunosuppressant and oncologic drugs.

Conclusions

This study constitutes the first large-scale study on drug-associated hyperammonaemia. This description may prove useful for clinicians in patients’ care as well as for trial design.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01026-4.

Diagnosis and management of 5-fluorouracil (5-FU)-induced acute leukoencephalopathy: lessons learnt from a single-Centre case series

Background

The administration of 5-fluorouracil (5FU) in the treatment of gastrointestinal (GI) malignancies is associated with common side effects such as mucositis, diarrhoea, and myelosuppression, which are easily managed with supportive measures and dose adjustments. Cardiotoxicity and neurotoxicity are rare but reversible side effects of 5-FU and are treated with withdrawal of the drug and conservative measures. The presenting symptoms of 5-FU-induced leukoencephalopathy are often confusing and pose a diagnostic dilemma in routine clinical practice.

Methods

We report a series of five patients with GI malignancies who developed 5-FU-induced leukoencephalopathy.

Results

All (n = 5) had Naranjo scores of 6–7, predictive of 5-FU-related adverse effects, with clinical and radiological findings suggestive of 5-FU-induced encephalopathy as described in prior literature. The median time to onset of symptoms from initiation of 5FU was 3 days (range: 2–4 days). All patients improved after conservative management with complete neurological recovery.

Conclusion

Prompt recognition of this rare yet severe adverse effect of 5-FU-based chemotherapy aids early withdrawal of the offending agent (5-FU) and timely initiation of supportive measures and helps plan alternative oncological interventions.

Hyperammonemic Encephalopathy Associated with 5-Flurouracil Infusion in Head and Neck Cancer: Case Report and Review of the Literature

Hyperammonemic encephalopathy is an uncommon, potentially lethal adverse effect of 5-fluorouracil (5-FU). Being one of the most common and versatile chemotherapy agents, it is important to understand this important side effect of 5FU. There is paucity of data in this subject. Here, we report a case of 5FU-induced encephalopathy in a patient on induction chemotherapy for head and neck cancer. In this case report, the clinical presentation, diagnosis, and management of 5FU-induced encephalopathy is reported.

Risk factors of mFOLFOX6-induced hyperammonemia in patients with colorectal cancer: an observational study

BACKGROUND

FOLFOX therapy, a standard treatment for colorectal cancer (CRC), causes a rare, but serious adverse event, hyperammonemia. However, the risk factors of hyperammonemia remain unknown.

METHODS

We examined 74 patients who received mFOLFOX6 therapy with or without biologics for CRC between April 2013 and March 2018 in Yaizu City Hospital. Clinicopathological factors were retrospectively reviewed in association with hyperammonemia, and risk factors of hyperammonemia during mFOLFOX6 therapy were analyzed in 32 patients with the available data.

RESULTS

Seven patients developed hyperammonemia, with onset exclusively on day 2 or 3 in the first cycle of therapy. They were treated with branched chain amino acid administration and hydration; however, one patient with stage G4 chronic kidney disease (CKD) died. By multivariate analysis, estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² was independently associated with hyperammonemia during FOLFOX therapy (odds ratio: 9.0, p = 0.040).

CONCLUSIONS

Reduced eGFR is considered a risk factor of developing hyperammonemia during FOLFOX therapy. Serum ammonia levels should be monitored especially during the first cycle of FOLFOX therapy in patients with CKD stage G3 or higher.