Ethylene glycol poisoning in a child treated with 4-methylpyrazole

Novel Technique for Simultaneous Ethylene Glycol and Its Metabolites Determination in Human Whole Blood and Urine Samples Using GC-QqQ-MS/MS

Toxicological analyses often necessitate the identification of compounds belonging to diverse functional groups. For GC-MS analyses, derivatization of compounds belonging to different functional groups can pose a challenge and requires the development of comprehensive methods of analysis. One example could be ethylene glycol, whose widespread use is related to possible unintentional or suicidal intoxications. This fact clearly indicates the need to develop sensitive methods for the determination of ethylene glycol and its metabolites in biological material, as only such complex analysis allows for proper toxicological expertise. A simultaneous GC-QqQ-MS/MS method for the determination of ethylene glycol together with its metabolites, glyoxal and glycolic acid, as well as the detection of glyoxylic acid and oxalic acid, was developed and fully validated. A novel approach for simultaneous derivatization of substances from different groups (alcohols, aldehydes, and carboxylic acids) was established. Sample preparation included the addition of three internal standards (BHB-d4, ethylene glycol-d4 and methylglyoxal), precipitation with acetonitrile and subsequent derivatization with N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA), as well as pentafluorophenylhydrazine (PFPH). Detection was carried out with the use of triple quadrupole mass spectrometer. The ionization method was electron impact, and quantitative analysis was carried out in multiple reaction monitoring mode. The lower limit of quantification was 1 μg/mL, 0.1 μg/mL, and 500 μg/mL for ethylene glycol, glyoxal, and glycolic acid, respectively. The presented method was applied in three authentic postmortem cases of ethylene glycol intoxication.

Effects of diethylene glycol contamination of pharmaceutical products on unexplained acute kidney injury in children: a systematic review

Unexplained acute kidney injury (AKI) in children owing to diethylene glycol (DEG) contamination during drug production has gained attention in recent years. This qualitative study investigated the effects of DEG exposure on the incidence of unknown AKI in children. A systematic review following the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines was proposed to search for studies using predefined search terms in the PubMed, EBSCO, and Web of Science data-bases without publication date restrictions. The inclusion criteria are observational study, case study, case report, and case series design; and having provided accurate data for DEG poisoning and AKI diagnosis in children. All authors performed the study screening, data extraction, and data synthesis processes. Consensus was reached by mutual agreement. The data synthesis was conducted according to the DEG and unexplained AKI in children by examining the statistical data using Microsoft Excel 2017 and storing the data using the cloud service of Universitas Islam Indonesia. Of the 115 included studies, 21 met the inclusion criteria, including 2 case-control studies, 1 cross-sectional study, 4 case studies, and 14 case reports. DEG-contaminated paracetamol caused unexplained AKI in children. Other drugs including cough expectorants, antihistamines, and sedatives were administered. Chemicals other than DEG, such as propylene glycol and ethylene glycol, also induce AKI owing to overprescription and unintentional exposure. A recent epidemic of unexplained AKI showed contaminated paracetamol as the poisoning agent regardless of formula.

Extracorporeal treatment for ethylene glycol poisoning: systematic review and recommendations from the EXTRIP workgroup

Ethylene glycol (EG) is metabolized into glycolate and oxalate and may cause metabolic acidemia, neurotoxicity, acute kidney injury (AKI), and death. Historically, treatment of EG toxicity included supportive care, correction of acid-base disturbances and antidotes (ethanol or fomepizole), and extracorporeal treatments (ECTRs), such as hemodialysis. With the wider availability of fomepizole, the indications for ECTRs in EG poisoning are debated. We conducted systematic reviews of the literature following published EXTRIP methods to determine the utility of ECTRs in the management of EG toxicity. The quality of the evidence and the strength of recommendations, either strong ("we recommend") or weak/conditional ("we suggest"), were graded according to the GRADE approach. A total of 226 articles met inclusion criteria. EG was assessed as dialyzable by intermittent hemodialysis (level of evidence = B) as was glycolate (Level of evidence = C). Clinical data were available for analysis on 446 patients, in whom overall mortality was 18.7%. In the subgroup of patients with a glycolate concentration ≤ 12 mmol/L (or anion gap ≤ 28 mmol/L), mortality was 3.6%; in this subgroup, outcomes in patients receiving ECTR were not better than in those who did not receive ECTR. The EXTRIP workgroup made the following recommendations for the use of ECTR in addition to supportive care over supportive care alone in the management of EG poisoning (very low quality of evidence for all recommendations): i) Suggest ECTR if fomepizole is used and EG concentration > 50 mmol/L OR osmol gap > 50; or ii) Recommend ECTR if ethanol is used and EG concentration > 50 mmol/L OR osmol gap > 50; or iii) Recommend ECTR if glycolate concentration is > 12 mmol/L or anion gap > 27 mmol/L; or iv) Suggest ECTR if glycolate concentration 8-12 mmol/L or anion gap 23-27 mmol/L; or v) Recommend ECTR if there are severe clinical features (coma, seizures, or AKI). In most settings, the workgroup recommends using intermittent hemodialysis over other ECTRs. If intermittent hemodialysis is not available, CKRT is recommended over other types of ECTR. Cessation of ECTR is recommended once the anion gap is < 18 mmol/L or suggested if EG concentration is < 4 mmol/L. The dosage of antidotes (fomepizole or ethanol) needs to be adjusted during ECTR.

Treating ethylene glycol poisoning with alcohol dehydrogenase inhibition, but without extracorporeal treatments: a systematic review

CONTEXT

Ethylene glycol is metabolized to toxic metabolites that cause acute kidney injury, metabolic acidemia, and death. The treatment of patients with ethylene glycol poisoning includes competitively inhibiting alcohol dehydrogenase with ethanol or fomepizole to prevent the formation of toxic metabolites, and extracorporeal treatments such as hemodialysis to remove ethylene glycol and its metabolites. In the absence of significant metabolic acidemia or kidney injury, it is hypothesized that extracorporeal treatments may be obviated without adverse outcomes to the patient if alcohol dehydrogenase inhibitors are used.

OBJECTIVES

The objectives of this study are to: (1) identify indicators predicting ADH inhibitor failure in patients with ethylene glycol poisoning treated with either ethanol or fomepizole for whom extracorporeal treatment was not performed (aside from rescue therapy, see below) (prognostic study), and (2) validate if the anion gap, shown in a previous study to be the best surrogate for the glycolate concentration, is associated with acute kidney injury and mortality (anion gap study).

METHODS

We conducted a systematic review to identify all reported patients with ethylene glycol poisoning treated without extracorporeal treatments but with either fomepizole (fomepizole monotherapy) or ethanol (ethanol monotherapy). Analyses were performed using both one case per patient and all cases (if multiple events were reported for a single patient). Data were compiled regarding poisoning, biochemistry, and outcomes. Treatment failure was defined as mortality, worsening of acid-base status, extracorporeal treatments used as rescue, or a worsening of kidney or neurological function after alcohol dehydrogenase inhibition was initiated. Also, we performed an analysis of previously described anion gap thresholds to determine if they were associated with outcomes such as acute kidney injury and mortality.

RESULTS

Of 115 publications identified, 96 contained case-level data. A total of 180 cases were identified with ethanol monotherapy, and 231 with fomepizole monotherapy. Therapy failure was noted mostly when marked acidemia and/or acute kidney injury were present prior to therapy, although there were cases of failed ethanol monotherapy with minimal acidemia (suggesting that ethanol dosing and/or monitoring may not have been optimal). Ethylene glycol dose and ethylene glycol concentration were predictive of monotherapy failure for ethanol, but not for fomepizole. In the anion gap study (207 cases), death and progression of acute kidney injury were almost nonexistent when the anion gap was less than 24 mmol/L and mostly observed when the anion gap was greater than 28 mmol/L.

CONCLUSION

This review suggests that in patients with minimal metabolic acidemia (anion gap <28 mmol/L), fomepizole monotherapy without extracorporeal treatments is safe and effective regardless of the ethylene glycol concentration. Treatment failures were observed with ethanol monotherapy which may relate to transient subtherapeutic ethanol concentrations or very high ethylene glycol concentrations. The results are limited by the retrospective nature of the case reports and series reviewed in this study and require prospective validation.

Selective oxidation passing through η3-ozone intermediates: applications to direct propene epoxidation using molecular oxygen oxidant

An unprecedented catalytic route for selective oxidation is designed that passes through η³-ozone intermediates and uses molecular oxygen as the oxidant without requiring a coreductant. DFT-computed reaction cycles identify a new catalyst type with the lowest computed overall activation energy for direct propene epoxidation for any catalyst to date.

Ethylene glycol poisoning: quintessential clinical toxicology; analytical conundrum

Ethylene glycol poisoning is a medical emergency that presents challenges both for clinicians and clinical laboratories. Untreated, it may cause morbidly or death, but effective therapy is available, if administered timely. However, the diagnosis of ethylene glycol poisoning is not always straightforward. Thus, measurement of serum ethylene glycol, and ideally glycolic acid, its major toxic metabolite in serum, is definitive. Yet measurement of these structurally rather simple compounds is but simple. This review encompasses an assessment of analytical methods for the analytes relevant for the diagnosis and prognosis of ethylene glycol poisoning and of the role of the ethylene glycol metabolites, glycolic and oxalic acids, in its toxicity.

Treatment of patients with ethylene glycol or methanol poisoning: focus on fomepizole

Ethylene glycol (EG) and methanol are responsible for life-threatening poisonings. Fomepizole, a potent alcohol dehydrogenase (ADH) inhibitor, is an efficient and safe antidote that prevents or reduces toxic EG and methanol metabolism. Although no study has compared its efficacy with ethanol, fomepizole is recommended as a first-line antidote. Treatment should be started as soon as possible, based on history and initial findings including anion gap metabolic acidosis, while awaiting measurement of alcohol concentration. Administration is easy (15 mg/kg-loading dose, either intravenously or orally, independent of alcohol concentration, followed by intermittent 10 mg/kg-doses every 12 hours until alcohol concentrations are <30 mg/dL). There is no need to monitor fomepizole concentrations. Administered early, fomepizole prevents EG-related renal failure and methanol-related visual and neurological injuries. When administered prior to the onset of significant acidosis or organ injury, fomepizole may obviate the need for hemodialysis. When dialysis is indicated, 1 mg/kg/h-continuous infusion should be provided to compensate for its elimination. Side-effects are rarely serious and with a lower occurrence than ethanol. Fomepizole is contraindicated in case of allergy to pyrazoles. It is both efficacious and safe in the pediatric population, but is not recommended during pregnancy. In conclusion, fomepizole is an effective and safe first-line antidote for EG and methanol intoxications.

Fomepizole for the treatment of pediatric ethylene and diethylene glycol, butoxyethanol, and methanol poisonings

INTRODUCTION

The use and clinical efficacy of the alcohol dehydrogenase inhibitor fomepizole is well established for the treatment of ethylene glycol and methanol poisonings in adults.

METHODS

A computerized search of the U.S. National Academy of medicine and EMBase databases was undertaken to identify published cases of patients treated with fomepizole. This search strategy identified 14 published cases related to the topic of this review: 10 due to ethylene glycol poisoning, 1 due to diethylene glycol poisoning, 1 due to butoxyethanol ingestion, and 2 due to methanol poisoning. The median age of these cases was 5.5 years old. FOMEPIZOLE IN GLYCOL AND GLYCOL ETHER POISONING: For the 10 ethylene glycol poisoned patients, the median recorded values of their arterial pH was 7.27 (range 7.03-7.38), serum bicarbonate concentration was 13 mEq/L (range 2-25), and ethylene glycol concentration was 2,140 mg/L (range 130-3,840). Eight of these patients were not hemodialyzed. The eight patients who were not hemodialyzed had ethylene glycol concentrations as high as 3,500 mg/L and serum bicarbonate concentrations as low as 4 mEq/L. All 10 patients had resolution of their metabolic acidosis and recovered without sequelae. The half-times of ethylene glycol elimination ranged from 9 to 15 h during fomepizole therapy, which is faster than the 19.7 h reported in adults. The two patients who ingested diethylene glycol or butoxyethanol all recovered without sequelae. The patient who ingested the butoxyethanol had a serum bicarbonate concentration of 13 mEq/L and was not hemodialyzed. FOMEPIZOLE IN METHANOL POISONING: One of the two children who ingested methanol was hemodialyzed. Both cases had a similar degree of severity. DOES FOMEPIZOLE OBVIATE THE NEED FOR HEMODIALYSIS?: Based on the experience reviewed herein it appears that, as in adults, hemodialysis may not be necessary in most cases of pediatric ethylene glycol poisoning if treated with fomepizole. FOMEPIZOLE PHARMACOKINETICS: Plasma fomepizole concentrations were measured in three cases and were found to be therapeutic with apparent Michaelis-Menton kinetics, having a zero-order elimination rate of 0.6-1 mg/L/h at higher concentrations and a first-order elimination with an apparent elimination half-time of 3.9 h at lower concentrations. FOMEPIZOLE REGIMEN: Most cases used the current U.S.-approved regimen. ADVERSE EFFECTS OF FOMEPIZOLE: The one adverse effect reported during fomepizole therapy was transient nystagmus in a 6-year-old with a serum ethylene glycol concentration of 130 mg/L and a serum bicarbonate concentration of 2 mEq/L; it is likely that ethylene glycol itself was the cause. COMPARISON OF FOMEPIZOLE WITH ETHANOL THERAPY: Two cases were originally treated with ethanol but switched to fomepizole because of adverse effects. In both cases, the adverse reactions to ethanol resolved once fomepizole treatment was initiated.

CONCLUSIONS

The limited data available suggest that fomepizole, using the same dosage regimen as that used for adults, is efficacious and well tolerated in pediatric patients. In many cases of pediatric ethylene glycol poisoning treated with fomepizole, hemodialysis may not be necessary despite high concentrations and the presence of metabolic acidosis.

Massive ethylene glycol ingestion treated with fomepizole alone-a viable therapeutic option

Fomepizole is used to treat and prevent toxicity from ethylene glycol poisoning. Treatment with fomepizole without hemodialysis in massive ethylene glycol ingestion has been rarely reported in the literature; however, published literature and practice guidelines recommend considering dialysis for ethylene glycol levels >50 mg/dL. We report a case of massive ethylene glycol ingestion resulting in the highest serum ethylene glycol concentration in a patient without ethanol co-ingestion who was treated with fomepizole and was not hemodialyzed. A 48-year-old male presented to the emergency department after reportedly ingesting >1 liter of antifreeze in an attempt at self-harm. He denied concomitant ethanol consumption. His initial presenting serum ethylene glycol level was 700 mg/dL, with normal renal function, and a metabolic acidosis with a high anion gap. One hour after presentation, he was started on intravenous fomepizole. Treatment with fomepizole continued until the patient's plasma ethylene glycol concentration was 16 mg/dL. His metabolic acidosis quickly resolved, he had no adverse reactions to the treatment, and his renal function remained normal. Ultimately, he was discharged to a psychiatric unit without sequelae. Published literature and practice guidelines suggests considering hemodialysis initiation in patients with an ethylene glycol level > 50 mg/dL. This recommendation is anecdotally, rather than evidence, based. With the potential risks inherent in hemodialysis, our case provides evidence that treatment with fomepizole without hemodialysis appears to be a viable alternative option in patients with even extremely high plasma ethylene glycol concentrations as long as their renal function is intact.

Non-drug-induced nephrotoxicity

Several drugs and other compounds can induce acute and/or chronic nephrotoxicity. The goal of this study was to review clinical features of nephrotoxicity induced by 'atypical' or 'unconventional' agents, such as environmental agents (metals, minerals, animals), food agents (mushrooms, aristolochic acid, medicinal traditional herbals, dietary supplements, melamine), drugs, and other products (ethylene glycol). Nephrotoxicity varies according to local background, dependent on different food and cultural customs, as well as to differences in local fauna and flora. The incidence of such a phenomenon is not well known. Many different pathophysiological pathways are involved, and the spectrum of renal lesions is rather wide. 'Epidemic nephrotoxicity' may occur, as recently illustrated by the melamine epidemics in Chinese infants receiving powdered milk formulas; a rapid reaction to unusual increased frequency of acute kidney injury and nephrolithiasis in young children has led to a rapid analysis from international experts, with subsequent recommendations for diagnosis and care. Nephrotoxicity should be considered when there is any unexplained renal impairment, especially in children.

Ethylene glycol ingestion treated only with fomepizole

INTRODUCTION

Ethylene glycol is a widely used chemical that is capable of causing significant injury if ingested. Treatment for ethylene glycol poisoning typically includes basic supportive care, alcohol dehydrogenase inhibition, and hemodialysis. Recent data have suggested that hemodialysis may not be necessary for cases of ethylene glycol poisoning that can be treated with fomepizole as blocking therapy before acidosis or renal dysfunction develops.

CASE REPORT

A 33-year-old man presented to the emergency department 1 hour after drinking approximately 1/2 gallon of ethylene glycol antifreeze and an unknown quantity of beer. On arrival he was mildly inebriated but otherwise displayed no other features of ethylene glycol poisoning. Fomepizole therapy was initiated and initial laboratory studies later revealed an osmol gap of 157 mOsm and an ethylene glycol concentration of 706 mg/dL. Nephrology and toxicology services were consulted. Over the next 3 days, fomepizole therapy was continued while the patient's acid-base status and renal function were closely monitored. No evidence of acid-base abnormalities or renal impairment was ever observed and the patient was discharged to psychiatric care on the fourth hospital day.

DISCUSSION

This report describes the case of a patient who presented soon after a massive ingestion of ethylene glycol with very high serum concentrations. He was successfully treated using fomepizole and basic supportive care. Our patient developed neither renal insufficiency nor metabolic acidosis. His concomitant ethanol consumption, early presentation, and treatment likely contributed to his favorable outcome. This case report underscores the effectiveness of supportive care and fomepizole in the treatment of ethylene glycol poisoning.

Does unintentional ingestion of ethylene glycol represent a serious risk?

The objective of this study was to evaluate data retrospectively on accidental ingestion of ethylene glycol (EG), based on calls to the Czech Toxicological Information Centre and from toxicological laboratories, in the years 2000-2004. All patients who ingested a known amount of EG and/or subjects with measured serum EG levels were included. A variety of clinical and laboratory parameters was collected. The medical records of 86 subjects, who had ingested from one to three swallows of EG, were analysed. The following findings emerged-metabolic acidosis (41%), vomiting (36%), nephrotoxicity (10%), and CNS depression (9%). In 15 children, the time interval between ingestion and hospitalisation was 1 hour or less. Ethanol was given to 12 children (four as first aid), and none developed hypoglycaemia. Of the 71 adults, 93% were treated with ethanol (19 as first aid). No side effects were documented. Seventeen patients received haemodialysis (HD). Two patients recovered without HD; their EG levels were higher than in the HD-treated patients. Unintentional EG ingestion usually involves ingestion of a small amount of EG, and was connected with mild signs of intoxication. Early therapy with ethanol alone appears sufficient in such cases, and represents no risk of adverse effects.

Successful therapy of paediatric ethylene glycol poisoning: a case report and annual survey by a regional poison centre

Severe poisoning with ethylene glycol, often used as antifreeze, is a rare, life-threatening event. Neurological symptoms are accompanied by metabolic acidosis with elevated anion gap and osmotic gap. We report on a 7-year-old boy suffering from severe ethylene glycol intoxication. Early diagnosis based on typical clinical signs and rapid initiation of specific therapy with ethanol resulted in complete and rapid recovery without haemodialysis becoming necessary. While one laboratory initially had not been able to detect ethylene glycol in the patient's blood, an ethylene glycol serum level of 3900 mg/L was measured by a second laboratory, the highest value ever reported in the scientific literature for paediatric cases. Ethylene glycol poisoning is verified by quantitative glycol analysis in serum, but only few laboratories are able to perform this investigation in emergency cases. Therefore, in the beginning diagnosis has to be based on patient's history and clinical signs. Every substantial suspicion of ethylene glycol poisoning has to be treated with an antidote (fomepizole or ethanol) immediately.

CONCLUSION

Ethylene glycol poisoning is rare in the paediatric age group in our series of glycol poisonings. One should keep in mind, that early diagnosis and treatment due to clinical signs is important and haemodialysis usually is not necessary.

Fomepizole as a therapeutic strategy in paediatric methanol poisoning. A case report and review of the literature

Methanol poisoning is not frequently observed in children; however, without treatment, serious intoxication can be complicated by visual impairment, coma, metabolic acidosis, respiratory and circulatory insufficiency and death. Treatment in a paediatric intensive care is therefore compulsory. Methanol is metabolised in the liver by alcohol dehydrogenase to the toxic metabolites formaldehyde and formic acid. Classically, ethanol is given as a competitive inhibitor in order to avoid the formation of these compounds. We report on the use of fomepizole (4-methylpyrazole),a new and potent inhibitor of alcohol dehydrogenase, in a 3-year-old boy after the intake of a toxic amount of methanol. The course was uneventful and the use of fomepizole was not accompanied by any side-effects. An overview is given of all cases of paediatric poisoning in which fomepizole was used.

CONCLUSION

Fomepizole seems to be a safe and valid alternative to ethanol in cases of paediatric methanol poisoning.

Incorporation of therapeutic interventions in physiologically based pharmacokinetic modeling of human clinical case reports of accidental or intentional overdosing with ethylene glycol

Although occupational uses of the high production volume (HPV) chemical ethylene glycol (EG) have not been associated with adverse effects, there are case reports where humans have either intentionally or accidentally ingested large quantities of EG, primarily from antifreeze. The acute toxicity of EG can proceed through three stages, each associated with a different metabolite: central nervous system depression (ethylene glycol), cardiopulmonary effects associated with metabolic acidosis (glycolic acid), and ultimately renal toxicity (oxalic acid), depending on the total amounts consumed and the effectiveness of therapeutic interventions. A physiologically based pharmacokinetic (PBPK) model developed in a companion paper (Corley et al., 2005). Development of a physiologically based pharmacokinetic model for ethylene glycol and its metabolite, glycolic acid, in rats and humans. Toxicol. Sci., in press 2005) was refined in this study to include clinically relevant treatment regimens for EG poisoning such as hemodialysis or metabolic inhibition with either ethanol or fomepizole. Such modifications enabled the model to describe data from several human case reports, confirming the ability of the previous model to describe the pharmacokinetics of EG and its metabolite, glycolic acid, in humans across a broad range of doses and multiple exposure routes. By integrating the case report data sets with controlled studies in this PBPK model, it was demonstrated that fomepizole, if administered early enough in a clinical situation, can be more effective than ethanol or hemodialysis in preventing the metabolism of EG to more toxic metabolites. Hemodialysis remains an important option, however, if treatment is instituted after a significant amount of EG is metabolized or if renal toxicity has occurred.

Treatment of severe pediatric ethylene glycol intoxication without hemodialysis

BACKGROUND

There is limited experience treating severe ethylene glycol poisoning in children without hemodialysis. The objective of this study was to describe the clinical course and outcome of severe pediatric ethylene glycol poisoning treated without hemodialysis.

METHODS

Patient records were identified retrospectively by hospital discharge diagnosis (ICD-9 code) of ethylene glycol poisoning from 1999 through 2002 at a pediatric medial center. Patients with initial serum ethylene glycol concentrations less than 50 mg/dL or those who received hemodialysis were excluded.

RESULTS

Six patients with an age range of 22 months to 14 years were admitted for treatment of ethylene glycol poisoning over a four-year period. Initial serum ethylene glycol concentrations ranged from 62 to 304 mg/dL (mean 174.0 mg/dL). The lowest-measured individual serum bicarbonates ranged from 4 to 17 mEq/L. All patients were initially admitted to intensive care. One patient received ethanol only, two patients received fomepizole only, and three patients received a loading dose of ethanol and then were converted to fomepizole therapy. None of the patients received hemodialysis. Treatment was continued until the serum ethylene glycol was less than 10 mg/dL. Metabolic acidosis resolved with intravenous fluid and supplemental bicarbonate within 24h. All patients had a normal creatinine upon presentation and at discharge. The mean length of stay in intensive care was 21h and on the ward was 33.7h. One episode of hypoglycemia occurred in a 22-month-old. All patients recovered without evidence of renal insufficiency or other major complications at discharge.

CONCLUSION

Six pediatric patients with severe ethylene glycol intoxication and normal renal function were successfully treated without hemodialysis.

Fomepizole alone for severe infant ethylene glycol poisoning

OBJECTIVE

To report a case of a massive ingestion of ethylene glycol in an infant successfully treated by fomepizole without hemodialysis.

DESIGN

Descriptive case report.

SETTING

Pediatric intensive care unit.

PATIENT

A 5-mo-old boy who ingested 200 mL of an antifreeze solution.

INTERVENTIONS

Antidotal therapy with a total of seven doses of fomepizole administered intravenously with an interval of 12 hrs (15 mg/kg as loading dose, then 10 mg/kg). Hemodialysis was not performed.

MEASUREMENTS AND MAIN RESULTS

Iterative determination of ethylene glycol concentration was obtained in blood and urine. Kinetics were calculated for ethylene glycol and fomepizole elimination. The infant made a complete recovery with no change in renal function.

CONCLUSIONS

Although not yet approved for this indication in the child, fomepizole seemed safe and effective in a case of severe ethylene glycol poisoning, without the need for hemodialysis.

Role of fomepizole in the management of ethylene glycol toxicity

OBJECTIVE

To systematically review English-language articles on fomepizole administration in patients with ethylene glycol poisoning.

DATA SOURCES

MEDLINE, EMBASE, Current Contents, and PubMed. Search terms were fomepizole, 4-methylpyrazole, and ethylene glycol. The search was supplemented with a bibliographic review of all relevant articles.

STUDY SELECTION

All published reports of fomepizole administration in patients with ethylene glycol poisoning were reviewed, irrespective of study design. We identified one clinical trial and subsequent pharmacokinetic study, one case series, and 13 case reports.

RESULTS

Fomepizole has been investigated in 70 patients in open, unblinded studies. Most patients received an intravenous loading dose, with subsequent variable maintenance doses every 12 hours until plasma ethylene glycol levels became undetectable. Additional hemodialysis treatment generally was administered when patients had renal insufficiency or ethylene glycol levels above 50 mg/dl. Many patients had detectable ethanol levels either because of coadministration or as a result of adjunctive treatment at a referring center. Poorer patient outcomes, such as death and renal insufficiency, were associated with later clinical presentation time after ingestion. At therapeutic fomepizole levels (> 8.6 mg/ml), the half-life of ethylene glycol was prolonged to over 19 hours. Fomepizole appeared to be well tolerated by most patients.

CONCLUSION

Fomepizole is an effective alcohol dehydrogenase inhibitor that decreases production of ethylene glycol metabolites. Reduced mortality and morbidity are undetermined because of the small number of patients evaluated to date. Data on comparative efficacy of fomepizole versus ethanol and data on administration of fomepizole in children are limited.

Nystagmus secondary to fomepizole administration in a pediatric patient

BACKGROUND

Fomepizole is an alcohol dehydrogenase inhibitor used to treat ethylene glycol poisoning in adults, with only one report describing the use of fomepizole in the pediatric population. We report a case of nystagmus associated with fomepizole treatment of a 6-year-old female who ingested ethylene glycol 15 hours prior to admission.

CASE REPORT

A previously healthy 6-year-old presented to the emergency department mottled, comatose, and with Kussmaul respirations. Initial arterial blood gases: pH 7.11, PO2 200, HCO3 2, base excess -29, and within 20 minutes her pH dropped to 7.03. The patient was responsive to pain only. Initially, crystalluria without fluorescence was observed in the emergency department; 2 hours after admission, the urine fluoresced under Wood's light. Laboratory data were significant for increased anion and osmolar gaps. She was fluid-resuscitated, NaHCO3, thiamine, and pyridoxine were administered, and she was admitted to the pediatric intensive care unit. Within 4 hours of admission, a loading dose of fomepizole (15 mg/kg) was infused due to the severity of the patient's clinical status. Hemodialysis was initiated but discontinued temporarily due to catheter thrombus formation. The initial (3-hour postadmission) ethylene glycol concentration was 13 mg/dL. She developed coarse vertical nystagmus within 2 hours of fomepizole infusion. The ethylene glycol concentration was 5 mg/dL 3 hours after hemodialysis which then was discontinued. No further fomepizole was administered and the child recovered uneventfully.

CONCLUSION

There was no evidence of the more frequently cited adverse events, such as headache, nausea, and dizziness. Fomepizole has been incompletely evaluated in the pediatric population, and the nature and occurrence of adverse events have not been described adequately. The use of fomepizole appeared safe in this patient although she developed transient nystagmus.

Effects of ethanol and of alcohol dehydrogenase inhibitors on the reduction of N-acetylaspartate levels of brain in mice in vivo: a search for substances that may have therapeutic value in the treatment of Canavan disease

N-Acetylaspartate (NAA) is an important osmolyte in the vertebrate brain that participates in an intercompartmental metabolic cycle. It is synthesized primarily in neurons from L-aspartate (Asp) and acetyl-CoA and, after its regulated release, it is hydrolysed by aspartoacylase in an oligodendrocyte compartment to produce Asp and acetate. NAA also gives a strong 1H magnetic resonance spectroscopic signal, which has led to its widespread use as a neuronal marker. Utilizing this noninvasive technique, the NAA concentrations in normal brain and in brains exhibiting a variety of CNS disease syndromes have been studied. In normal individuals, the concentration of NAA has been observed to be relatively stable over long periods. However, in many CNS disease processes there are long-term changes in the level of NAA that have been considered to signal changes in neuron density or function. We report that the concentration of NAA in brain is malleable and that, in addition to normal endogenous variation or changes due to disease processes, it can be modified by a variety of exogenous drugs and other substances. As a result of this investigation, we have also been able to identify a new class of NAA-active compounds--pyrazole and pyrazole derivatives--that have the ability to reduce brain NAA concentrations in normal mice. The importance of these findings in understanding the NAA intercompartmental cycle, and its role in Canavan disease, a genetic aspartoacylase deficiency disease, are discussed.

Recent advancements in pediatric toxicology

Ingestion of potentially poisonous agents is a common reason for children to present to an emergency department. The clinician must decide whether gastrointestinal decontamination is indicated for these patients. The controversy over the type of gastrointestinal decontamination is resolving and recent recommendations are reviewed. Also two new antidotes, fomepizole for toxic alcohols and octreotide for sulfonylureas, are reviewed.