Pancreatic injury following acute methanol poisoning

Prognostic factors in acute poisoning with central nervous system xenobiotics: development of a nomogram predicting risk of intensive care unit admission

Background

Acute intoxication with central nervous system (CNS) xenobiotics is an increasing global problem. Predicting the prognosis of acute toxic exposure among patients can significantly alter the morbidity and mortality. The present study outlined the early risk predictors among patients diagnosed with acute exposure to CNS xenobiotics and endorsed bedside nomograms for identifying patients requiring intensive care unit (ICU) admission and those at risk of poor prognosis or death.

Methods

This study is a 6-year retrospective cohort study conducted among patients presented with acute exposure to CNS xenobiotics.

Results

A total of 143 patients' records were included, where (36.4%) were admitted to the ICU, and a significant proportion of which was due to exposure to alcohols, sedative hypnotics, psychotropic, and antidepressants (P = 0.021). ICU admission was associated with significantly lower blood pressure, pH, and HCO₃ levels and higher random blood glucose (RBG), serum urea, and creatinine levels (P < 0.05). The study findings indicate that the decision of ICU admission could be determined using a nomogram combining the initial HCO₃ level, blood pH, modified PSS, and GCS. HCO₃ level < 17.1 mEq/L, pH < 7.2, moderate-to-severe PSS, and GCS < 11 significantly predicted ICU admission. Moreover, high PSS and low HCO₃ levels significantly predicted poor prognosis and mortality. Hyperglycemia was another significant predictor of mortality. Combining initial GCS, RBG level, and HCO₃ is substantially helpful in predicting the need for ICU admission in acute alcohol intoxication.

Conclusion

The proposed nomograms yielded significant straightforward and reliable prognostic outcomes predictors in acute exposure to CNS xenobiotics.

Acil Servise Başvuran Metil Alkol Zehirlenmelerinin Geriye Dönük Analizi

Objective: Methyl alcohol poisoning remains a significant cause of mortality and morbidity. This poisoning is still one of the important reasons for admission to emergency services. We aimed to examine the admission complaints, laboratory findings, treatment methods, clinical outcomes and examine the factors affecting the mortality of patients diagnosed with methyl alcohol poisoning in the emergency department. Methods: In this retrospective descriptive study, we analysed the patients who were considered to be diagnosed with methyl alcohol intoxication among those who came to our emergency department due to alcohol intoxication from June 1, 2018 to June 1, 2020. Results: The study included 20 (4.86%) individuals with methyl alcohol poisoning among 411 people who presented to the emergency department due to ethyl and methyl alcohol intake and resulting effects.The mean age of the patients was 47.35±14.2 years and 85% (n=17/20) were male. Upon reviewing the patients' admission symptoms, 70% were observed to have visual problems, 60% complaints of vomiting, 45% shortness of breath, and 40% changes in consciousness. In the study, it was revealed that 18.2%(n=2/11) females and 81.8%(n=9/11) males died, and the mortality rate was calculated as 55%(n=11/20). Conclusions: The presence of visual problems, hypotension, and coma in clinical findings, high anion gap metabolic acidosis, marked osmolar gap, an increase in lactate level, and hyperglycemia in laboratory findings may be the early signs of mortality in patients with methyl alcohol poisoning. Therefore, patients with these signs should be followed up more closely and treated.

Fatal methanol poisoning with different clinical and autopsy findings: Case report and literature review

Methanol poisoning is responsible for high morbidity and mortality, and the elevated concentration of methanol in the body is the major criteria for forensic diagnosis of methanol poisoning. However, in cases with lower methanol concentrations, diagnosis is mainly dependent on highly variable postmortem manifestations.Herein, we report a fatal methanol poisoning cases that two subjects ingested the same amount of methanol simultaneously, yet the subject one presented only non-specific gastrointestinal and mild central nervous system symptoms, while the other subject exhibited typical toxic manifestations with the exception of visual compromise. In autopsy, subject number 1 did not show typical pathological changes caused by methanol poisoning, except for the elevated levels of methanol in body fluids. On the contrary, bilateral basal ganglia hemorrhage and necrosis caused by methanol-induced brain lesion was observed in case number 2. Due to the complex and multifactorial process of methanol intoxication, many factors, including comprehensive autopsy, quantitative detection of methanol and formic acid, and genotype analysis, participate in its metabolism and toxicity, and can impact the clinical symptoms, prognosis and postmortem manifestations. Therefore, a combination of multiple diagnosis methods may more accurately contribute to the forensic diagnosis of methanol poisoning and should be tailored on an individual basis. This case report also reviews forensic diagnosis literature on methanol poisoning to provide a reference for forensic pathologists.

Acute pancreatitis due to methanol toxicity during the COVID-19 pandemic

Acute methanol poisoning may be associated with a variety of symptoms, such as abdominal pain, blurred vision, loss of consciousness, and acute pancreatitis. We present a 37-year-old man with acute pancreatitis due to methanol poisoning during the COVID-19 pandemic.

Methanol poisoning as a new world challenge: A review

BACKGROUND

Methanol poisoning (MP) occurs often via ingestion, inhalation, or dermal exposure to formulations containing methanol in base. Clinical manifestations of MP include gastrointestinal symptoms, central nervous system (CNS) suppression, and decompensated metabolic acidosis occurred with blurred vision and early or late blindness.

OBJECTIVE

This study reviewed the clinical manifestations, laboratory and radiology findings, and treatment approaches in MP.

DISCUSSION

Methanol is usually rapidly absorbed after ingestion and metabolized by alcohol dehydrogenase (ADH), then distributed to the body water to reach a volume distribution approximately equal to 0.77 L/kg. It is also eliminated from the body as unchanged parent compounds. Clinical manifestations of MP alone initiate within 0.5-4 h after ingestion and include gastrointestinal symptoms and CNS suppression. After a latent period of 6-24 h, depending on the absorbed dose, decompensated metabolic acidosis occurs with blurred vision and early or late blindness. Blurred vision with normal consciousness is a strong suspicious sign of an MP. The mortality and severity of intoxication are well associated with the severity of CNS depression, hyperglycemia, and metabolic acidosis, but not with serum methanol concentration. After initial resuscitation, the most important therapeutic action for patients with known or suspected MP is correction of acidosis, inhibition of ADH, and hemodialysis.

CONCLUSION

Since MP is associated with high morbidity and mortality, it should be considered seriously and instantly managed. Delay in treatment may cause complications, permanent damage, and even death.

Acute and delayed toxicity from co-ingestion of methylene chloride and methanol

Methylene chloride is a volatile, chlorinated hydrocarbon and colorless solvent found in multiple industrial products including paint strippers, metal cleaners, automotive products, pesticides and aerosol containers. Occupational exposure to methylene chloride is reported in automotive technicians, painters, and other industrial workers with adverse health effects including gastrointestinal, neurological, as well as hepato-renal injuries. International Agency for Research on Cancer (IARC) classifies methylene chloride as a 2 A carcinogen. Through a series of reactions catalyzed by cytochrome P450 2E1 (CYP2E1), metabolism of methylene chloride leads to the formation of formyl chloride, and ultimately carbon monoxide (CO). Most reports of methylene chloride toxicity are due to dermal and inhalational exposure in occupational settings. Ingestion of methylene chloride is uncommon, yet can lead to significant toxicity and prolonged CO toxicity. Methylene chloride is frequently formulated with methanol; individuals who intentionally ingest methylene chloride can experience concomitant methanol toxicity. We present a case of acute ingestion of paint stripper containing methanol and methylene chloride. We discuss the clinical presentation, key management decisions, relevant pathophysiology and biochemistry, as well as the clinical course and management.

Folate as an Adjuvant Therapy in Methanol Poisoning

Folate and its derivatives have long been used as an adjunctive treatment in methanol poisoning. Methanol is ultimately metabolized to formate, the toxic compound. The accumulation of formate can lead to acidemia, retinal damage, visual impairment, and death. Formate is converted to carbon dioxide and water in a folate-dependent manner, and folate is often given in cases of methanol poisoning. In this paper, the evidence for folate as an adjunctive therapy in methanol poisoning is reviewed.

Suicide following acute admissions for physical illnesses across England and Wales

BACKGROUND

The study aim was to establish and quantify suicide risk following acute admissions for all major physical illnesses, for confirmatory purposes, from two independent information sources from different countries.

METHODS

Record linkage of inpatient and death certificate data for 11 004 389 acute admissions for physical illnesses in England and 713 496 in Wales. The main outcome measure was standardised mortality ratios (SMRs) for suicide at 1 year following discharge from hospital.

RESULTS

There were 1781 suicides within 1 year of discharge in England (SMR = 1.7; 95% = 1.6-1.8) and 131 in Wales (SMR = 2.0; 1.7-2.3). Of 48 major physical illnesses that were associated with at least eight suicides in either country, there was high consistent suicide mortality (significant SMR >3) in both countries for constipation (SMR = 4.1 in England, 7.5 in Wales), gastritis (4.4 and 4.9) and upper gastrointestinal bleeding (3.4 and 4.5). There was high suicide mortality in one country for alcoholic liver disease, other liver disease and chronic pancreatitis; for epilepsy and Parkinson's disease; for diabetes, hypoglycaemia and hypo-osmolality & hyponatraemia; and for pneumonia, back pain and urinary tract infections.

CONCLUSIONS

There is little or no increased suicide mortality following acute admissions for most physical illnesses. Much of the increased suicide mortality relates to gastrointestinal disorders that are often alcohol related or specific chronic conditions, which may be linked to side effects from certain therapeutic medications. Acute hospital admissions for physical illnesses may therefore provide an opportunity for targeted suicide prevention among people with certain conditions, particularly alcohol related disorders.

Acute Renal Injury Following Methanol Poisoning: Analysis of a Case Series

The objective of this paper is to document the prevalence of indicators of acute renal injury in a series of methanol-poisoned patients treated in an intensive care unit and to discuss the possible mechanisms. This is a retrospective analysis of the medical records of 25 consecutive patients admitted to the intensive care unit after severe intentional methanol poisoning. Acute renal impairment was defined as a serum creatinine concentration higher than 177 μmol/L and/or a urinary output on admission and for the first 24 h below 0.5 ml/kg/h. Clinical pathological signs of acute renal injury were found in 15 patients. In comparison with the 10 other patients taken as control group, the patients who developed renal injury had a lower blood pH value on admission, a higher serum osmolality, and a higher peak formate concentration. Two factors contributing to renal injury could be identified: hemolysis and myoglobinuria. The role of osmotic changes (“osmotic nephrosis”) or of a direct cytotoxic effect of formic acid remains speculative. Analysis of proteinuria suggests that proximal tubular cells may be preferentially affected. Results of histopathological evaluation of the kidney on a limited sample size ( n = 5) were inconclusive but suggestive of possible hydropic changes in the proximal tubule secondary to methanol toxicity. Acute renal injury may be associated with other signs of severity in methanol poisoning, but it is almost always reversible in survivors. Indicators of acute renal injury were identified. The pathophysiology of this acute renal injury is multifactorial and far more complex than shock-related tubular necrosis.

Methanol and ethylene glycol intoxication

Accidental or intentional ingestion of substances containing methanol and ethylene glycol can result in death, and some survivors are left with blindness, renal dysfunction, and chronic brain injury. However, even in large ingestions, a favorable outcome is possible if the patient arrives at the hospital early enough and the poisoning is identified and appropriately treated in a timely manner. This review covers the common circumstances of exposure, the involved toxic mechanisms, and the clinical manifestations, laboratory findings, and treatment of methanol and ethylene glycol intoxication.

A systematic review of ethanol and fomepizole use in toxic alcohol ingestions

Objectives. The optimal antidote for the treatment of ethylene glycol or methanol intoxication is not known. The objective of this systematic review is to describe all available data on the use of ethanol and fomepizole for methanol and ethylene glycol intoxication. Data Source. A systematic search of MEDLINE and EMBASE was conducted. Study Selection. Published studies involving the use of ethanol or fomepizole, or both, in adults who presented within 72 hours of toxic alcohol ingestion were included. Our search yielded a total of 145 studies for our analysis. There were no randomized controlled trials, and no head-to-head trials. Data Extraction. Variables were evaluated for all publications by one independent author using a standardized data collection form. Data Synthesis. 897 patients with toxic alcohol ingestion were identified. 720 (80.3%) were treated with ethanol (505 Me, 215 EG), 146 (16.3%) with fomepizole (81 Me, 65 EG), and 33 (3.7%) with both antidotes (18 Me, 15 EG). Mortality in patients treated with ethanol was 21.8% for Me and 18.1% for EG. In those administered fomepizole, mortality was 17.1% for Me and 4.1% for EG. Adverse events were uncommon. Conclusion. The data supporting the use of one antidote is inconclusive. Further investigation is warranted.

Short-term immunological effects of non-ethanolic short-chain alcohols

Short-chain alcohols are embedded into several aspects of modern life. The societal costs emanating from the long history of use and abuse of the prototypical example of these molecules, ethanol, have stimulated considerable interest in its general toxicology. A much more modest picture exists for other short-chain alcohols, notably as regards their immunotoxicity. A large segment of the general population is potentially exposed to two of these alcohols, methanol and isopropanol. Their ubiquitous nature and their eventual use as ethanol surrogates are predictably associated to accidental or deliberate poisoning. This review addresses the immunological consequences of acute exposure to methanol and isopropanol. It first examines the general mechanisms of short-chain alcohol-induced biological dysregulation and then provides a tentative model to explain the molecular events that underlie the immunological dysfunction produced by methanol and isopropanol. The time-related context of serum alcohol concentrations in acute poisoning, as well as the clinical implications of their short-term immunotoxicity, is also discussed.

Hyperglycemia is a strong prognostic factor of lethality in methanol poisoning

Methanol poisoning is seen in the form of isolated episodes, or intentional ingestion and epidemics. Despite its efficient treatment, methanol poisoning has high morbidity and mortality rates. So far, several studies have been performed to identify the prognostic factors in methanol poisoning. Recently, during the treatment of patients with methanol poisoning, we observed that patients' blood glucose levels were high on presentation to the hospital, particularly in those who expired. Through a literature search, we found that no studies have been performed on blood glucose levels or hyperglycemia in methanol poisoning. Therefore, the present retrospective study was done as a preliminary investigation to understand whether there was a meaningful relationship between methanol poisoning and blood glucose level on presentation, and also if hyperglycemia could be considered as a prognostic factor for mortality. In this retrospective study, a review of the hospital charts was performed for all patients who were treated for methanol poisoning from March 2003 to March 2010 in two hospitals in Tehran, Iran. Those with definitive diagnosis of methanol poisoning, no history of diabetes mellitus, and normal or low body mass index (<25) were included. Patients' demographic information, clinical manifestations, time elapsed between ingestion and presentation, blood glucose level on presentation (before treatment), results of arterial blood gas analysis, and the clinical outcome were recorded. Statistical analysis was done using SPSS software (version 17, Chicago, Illinois, USA) and application of Mann-Whitney U test, Pearson's chi-square test, Pearson correlation coefficient (r), receiver operating characteristic (ROC) curve, and logistic regression. P values less than 0.05 were considered as the statistically significant levels. Ninety-five patients with methanol poisoning met the inclusion criteria and were included in the study. Of these, 91 (96%) were male and 4 (4%) were female. Mean age was 31.61 ± 14.3 years (range, 13 to 75). Among the 95 patients, 68 survived (72%) and 27 expired (28%). Median blood glucose level was 144 mg/dL (range, 75 to 500). There was no significant statistical correlation between blood glucose level and time of treatment, age, pCO(2), or serum bicarbonate concentration, but blood glucose level had a statistically significant correlation with pH (r = -0.242, P = 0.02) and base deficit (r = 0.230, P = 0.03). The mean blood glucose level was 140 ± 55 and 219 ± 99 mg/dL in the survivor and non-survivor patients, respectively (P < 001). Considering the cutoff level of 140 mg/dL for blood glucose and using logistic regression analysis, and adjusting according to the admission data with significant statistical difference in the two study groups, the odds ratio for hyperglycemia as a risk factor for death was 6.5 (95% confidence interval = 1.59-26.4). Our study showed that blood glucose levels were high in methanol poisoning and even higher in those who died in comparison with the survivors. Therefore, hyperglycemia might be a new prognostic factor in methanol poisoning, but further studies are needed to determine whether controlling hyperglycemia has therapeutic consequences.

Outcomes of visual disturbances after methanol poisoning

INTRODUCTION

Methanol poisoning and toxic optic neuropathy is still seen worldwide. Little attention has been paid to the persistent visual disturbances following methanol poisoning. We aimed to evaluate the outcomes of visual disturbances in methanol-poisoned patients referred to us with visual disturbances.

METHODS

This retrospective observational case series evaluated the outcomes of visual disturbances in patients with methanol poisoning hospitalized in Loghman Hakim and Hazrat Rasoul Akram hospitals between March 2003 and October 2009. Medical charts were evaluated for age, gender, time between consumption and hospital presentation, gastrointestinal symptoms, abnormal neurological findings at presentation and during hospital admission, arterial blood gas results, treatment modalities, history of chronic diseases, and status of vision at presentation and discharge from the hospital. The patients or their relatives were contacted 1 year after the admission date of the last patient and questioned about the status of the patients' vision at the time of hospital discharge, after discharge, and at the time of phone contacts.

RESULTS

A total of 50 patients with methanol poisoning and visual disturbances at presentation survived. Thirty-seven cases were followed; 16 showed visual disturbance improvement before hospital discharge, and 21 had visual disturbance after discharge. Visual disturbances were classified into two groups: severe to total blindness and blurred/snowfield vision. Patients were also grouped into one of four categories: group I: patients whose blurred or snowfield vision completely recovered within up to a maximum of 2 weeks after discharge (n=7); group II, the patients who were blind at the time of discharge (n=5) and partially recovered within a maximum of 3-4 weeks; group III, the patients who were blind at the time of discharge and gained no improvement in their vision (n=5); group IV, who were blind at the time of discharge, partially recovered within few days to approximately 1 month and experienced reduced vision and blindness after about a maximum of 9 months (n=4). Patients whose visual disturbances improved with treatment and the patients in group I were considered as transient (n=23) and groups II, III, and IV as permanent visual disturbance cases (n=14). Significant difference was not seen in age, sex, elapsed time to presentation, gastrointestinal symptoms, abnormal neurological and CT findings, and arterial blood gas results at presentation between the transient and permanent visual disturbance groups. No association existed between the visual disturbance and abnormal neurological and CT findings.

CONCLUSION

Blurred or snowfield vision in methanol poisoning resolved. However, outcomes of the blindness cannot be predicted. Insome patients, blindness improves but these patients eventually experience reduced vision afterwards.

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.

Methanol induces a discrete transcriptional dysregulation that leads to cytokine overproduction in activated lymphocytes

Methanol is an important cause of acute alcohol intoxication; it is ubiquitously present at home and in the workplace. Although the existing literature provides a reasonable insight into the immunological impact of ethanol and to a much lesser extent of isopropanol, much less data are available on methanol. We hypothesized on structural grounds that methanol would share the immunosuppressive properties of the two other short-chain alcohols. We report here that methanol increases the proliferative capacity of human T lymphocytes and synergizes with the activating stimuli to augment cytokine production. The cytokine upregulation was observed in vitro at methanol concentrations as low as 0.08% (25mM) as measured by interleukin-2, interferon-γ, and tumor necrosis factor-α release in T cells. Methanol did not affect the antigen receptor-mediated early signaling but promoted a selective and differential activation of the nuclear factor of activated T cells family of transcription factors. These results were further substantiated in a mouse model of acute methanol intoxication in which there was an augmented release of proinflammatory cytokines in the serum in response to the staphylococcal enterotoxin B. Our results suggest that methanol has a discrete immunological footprint of broad significance given the exposure of the general population to this multipurpose solvent.

Methanol poisoning: the duality between 'fast and cheap' and 'slow and expensive'

The management of methanol poisoning includes early antidote therapy to inhibit the metabolism of methanol to formate. Ethanol and fomepizole are both effective, but recently fomepizole has been preferred, although there is no scientific evidence that the use of fomepizole is a superior therapeutic strategy compared with the use of ethanol combined with haemodialysis. The same patient was admitted twice to our emergency department with methanol poisoning. The first time (methanol 3.24 g/l), she was treated with fomepizole without dialysis owing to the absence of acidosis. The second time (methanol 5.5 g/l), she received ethanol as an antidote and dialysis was started. For both therapeutic strategies, hospital length of stay, observation unit length of stay and costs are compared. In the Belgian healthcare system, we found that fomepizole treatment was three times as expensive as ethanol treatment, and the majority of costs are not reimbursed. Fomepizole antidote therapy, compared with ethanol, has fewer reported side effects, but is more expensive. In hospitals where dialysis is easily available, ethanol antidote therapy should still be considered, especially if similar cost differences exist within the healthcare system one is working in.

Methanol related deaths in Edirne

In this retrospective autopsy study, a detailed analysis of methanol related deaths in Trakya region of Turkey is presented and departmental autopsy records, toxicology and histopathology results are analyzed. We found that methanol poisonings comprise 2.83% of all forensic autopsies (n:18), 88.8% of the cases were male, most of the victims were aged between 41 and 45. Blood methanol concentrations range widely from 55 to 479 mg per 100ml. Ethyl alcohol was detected in 44.4% of the cases. Most of the cases died in hospital and were poisoned through the consumption of alcoholic beverages from illicit sources and colognes. It is important for physicians to be aware of methanol poisoning symptoms and for forensic pathologists to obtain samples for toxicology during autopsies. Some preventative strategies including to routine control of the stores, to prevent the production of illegal alcoholic beverages, etc. should be developed.

Current recommendations for treatment of severe toxic alcohol poisonings

BACKGROUND

Ethylene glycol (EG) and methanol are responsible for accidental, suicidal, and epidemic poisonings, resulting in death or permanent sequelae. Toxicity is due to the metabolic products of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase. Conventional management of these intoxications consists of ethanol and hemodialysis. Fomepizole, a potent ADH inhibitor, has largely replaced antidotal ethanol use in France and two recent prospective U.S. trials definitively established its efficacy. Fomepizole appears safer than ethanol and while no comparative study of efficacy exists, fomepizole is recommended as the first-line antidote.

FOCUS

Fomepizole, administered early in EG intoxication, prevents renal injury. In the absence of renal failure, EG clearance is rapid, avoiding the need for prolonged fomepizole administration. The long elimination half-life of methanol poisonings, with absent hemodialysis, necessitates prolonged administration of fomepizole. In the U.S. trials, patients were dialyzed when plasma EG or methanol concentrations were >/=0.5 g/l. However, EG-poisoned patients treated with fomepizole prior to the onset of significant acidosis may not require hemodialysis. Indeed, fomepizole may also obviate the need for hemodialysis in selected methanol-poisoned patients, in the absence of neurological and ocular impairment or severe acidosis. When dialysis is indicated, 1 mg.kg.h continuous infusion of fomepizole should be provided to compensate for its elimination.

CONCLUSIONS

Fomepizole is an effective and safe first-line recommended antidote for EG and methanol intoxication. In selected patients, fomepizole may obviate the need for hemodialysis.

Prélèvements d’organes après intoxication

BACKGROUND

There is an increasing gap between the number of patients on the waiting list and the number of transplanted patients. In France, more than 10000 patients waited for an organ transplantation in 2002. Due to the graft shortage, "marginal" donors are now considered. The patients who present brain death after accidental or voluntary poisoning belong to this category.

EPIDEMIOLOGY

The data available from European or North American organ procurement organisations show that poisoned donors represent about 1% of all organ donors. It seems likely that a significant number of poisoned patients are not referred because poisoning is regarded as a contraindication to organ donation. When organ procurement can be achieved, the results expressed as recipient survival or graft survival are quite encouraging.

TOXIC PRODUCTS

The most frequently involved toxins are either drugs (psychotropic agents, analgesics...), illicit substances, or environmental agents (gases, alcohols...). The literature data are discussed; some issues remain controversial.

PRACTICAL APPROACH

Several criteria have to be applied when poisoned patients are considered as potential organ donors. Besides a firm diagnosis of "brain death", the knowledge of the "target organs" of poisoning is of paramount importance, together with careful analysis of the toxicokinetics and toxicodynamics. In most cases, routine biological and morphological data are sufficient to assess graft function.

Toxicology in the critically ill patient

Intoxications present in many forms including: known drug overdose or toxic exposure, illicit drug use, suicide attempt, accidental exposure, and chemical or biological terrorism. A high index of suspicion and familiarity with toxidromes can lead to early diagnosis and intervention in critically ill, poisoned patients. Despite a paucity of evidence-based information on the management of intoxicated patients, a rational and systematic approach can be life saving.

Surgical issues in the poisoned patient

Some toxicologic emergencies require immediate or urgent surgical intervention in addition to routine medical care. The EP must be familiar with the indications for operative care, even though many of these poisonings and exposures are relatively rare. The EP must also be knowledgeable regarding the various means of surgical decontamination that are available, including temporary cardiopulmonary bypass. Finally, a high level of vigilance must be maintained for patients who have delayed presentation and fulminant organ failure necessitating early involvement of the transplantation team.

Rethinking the Toxic Methanol Level

INTRODUCTION

Treatment thresholds for methanol poisoning are based on case reports and published opinion. Most guidelines recommend treatment for a methanol level > or = 20 mg/dL in a nonacidotic patient. No supportive data have been offered nor has the time of the exposure been addressed. For instance, no distinction has been drawn between a methanol level drawn 1 hr vs. 24 hr from ingestion. We analyzed all published cases of methanol poisoning to determine the applicability of the 20 mg/dL threshold in a nonacidotic patient, specifically those arriving early for care (within 6 hr) with a peak or near-peak blood methanol concentration.

METHODS

Using predefined search criteria, a systematic review of the world literature was performed using MEDLINE and EMBASE. In addition, each article's references were hand searched for pre-1966 articles, as were fatality abstracts from all U.S. poison centers. Human cases were included if they reported a known time of a single methanol exposure, acid-base data, blood methanol, and blood ethanol (if not acidotic).

RESULTS

Dating to 1879, 372 articles in 18 languages were abstracted using a standard format; 329 articles (2433 patients) involved methanol poisoning, and 70 articles (173 patients) met inclusion criteria. Only 22 of these patients presented for care within 6hr of ingestion with an early methanol level. All but 1 patient was treated with an inhibitor of alcohol dehydrogenase (ADH). A clear acidosis developed only with a methanol level > or = 126 mg/dL. The patient that did not receive an ADH inhibitor was an infant with an elevated early methanol level (46 mg/dL) that was given folate alone and never became acidotic. Intra and inter-rater reliability were 0.95.

CONCLUSIONS

Nearly all reports of methanol poisoning involve acidotic patients far removed from ingestion. The small amount of data regarding patients arriving early show that 126 mg/dL is the lowest early blood methanol level ever clearly associated with acidosis. Contrary to conventional teaching, there are case reports of acidosis after only a few hours of ingestion. The data are insufficient to apply 20 mg/dL as a treatment threshold in a nonacidotic patient arriving early for care. Prospective studies are necessary to determine if such patients may be managed without antidotal therapy or dialysis.

What are the adverse effects of ethanol used as an antidote in the treatment of suspected methanol poisoning in children?

BACKGROUND

Ethanol used as an antidote is said to have various adverse effects, particularly in children. The rate of these adverse effects is not known.

METHODS

Twenty-one-year retrospective chart review (1980-2000) from suspected methanol poisoning patients treated with ethanol in two large pediatric tertiary care centers.

RESULTS

A total of 60 children (median age of 24 months) received ethanol for suspected methanol poisoning: 39 orally and 21 intravenously. Median initial methanol level was 4.16 mmol/L (13.3 mg/dL) (range 0 to 87.5 mmol/L or 0 to 280 mg/dL). Median duration of ethanol treatment was 16 hours (range 1.5 to 72 hours). None [0% (95% CI 0-5%)] of the 60 patients developed symptomatic hypoglycemia. Of the 50 patients that had a glucose level measured, none [(0% [95% CI 0-6%)] had a serum glucose concentration < 2.78 mmol/L (< 50 mg/dL). Eight patients [16% (95% CI 8-30%)] had at least one serum glucose concentration between 2.78-3.61 mmol/L (50-65 mg/dL), but none of those had symptoms compatible with hypoglycemia. A total of 42 patients [84% (95% CI 70-92%)] had all their serum glucose concentrations > 3.61mmol/L (> 65 mg/dL). There was no identifiable difference in the glucose intake between the serum glucose concentration groups. Six out of the 60 patients [10% (95% CI 4-21%)] were described as more drowsy after ethanol but none was comatose or needed intubation. No child showed signs of hypothermia [0/40 (95% CI 0-8%)] (rectal temperature < 35 degrees C), hepatotoxicity (0/12) (AST or ALT > 100 U/L) or even thrombophlebitis (0/21). None of the 22 patients with toxic levels of methanol (> or = 26.2 mmol/L- > or = 20 mg/dL) died or had ethanol-induced morbidity despite wide variation in ethanol levels.

CONCLUSION

The rate of clinically important adverse effects related to ethanol used as an antidote to treat methanol poisoning in children was either absent or low in a tertiary care pediatric hospital setting. There was no morbidity or mortality associated with ethanol when it was used despite wide variation in ethanol levels. These results suggest that with appropriate monitoring and intravenous glucose intake in a controlled environment such as a pediatric intensive care unit, ethanol therapy does not carry as many risks as currently believed.

American Academy of Clinical Toxicology practice guidelines on the treatment of methanol poisoning

EPIDEMIOLOGY

Almost all cases of acute methanol toxicity result from ingestion, though rarely cases of poisoning have followed inhalation or dermal absorption. The absorption of methanol following oral administration is rapid and peak methanol concentrations occur within 30-60minutes.

MECHANISMS OF TOXICITY

Methanol has a relatively low toxicity and metabolism is responsible for the transformation of methanol to its toxic metabolites. Methanol is oxidized by alcohol dehydrogenase to formaldehyde. The oxidation of formaldehyde to formic acid is facilitated by formaldehyde dehydrogenase. Formic acid is converted by 10-formyl tetrahydrofolate synthetase to carbon dioxide and water. In cases of methanol poisoning, formic acid accumulates and there is a direct correlation between the formic acid concentration and increased morbidity and mortality. The acidosis observed in methanol poisoning appears to be caused directly or indirectly by formic acid production. Formic acid has also been shown to inhibit cytochrome oxidase and is the prime cause of ocular toxicity, though acidosis can increase toxicity further by enabling greater diffusion of formic acid into cells.

FEATURES

Methanol poisoning typically induces nausea, vomiting, abdominal pain, and mild central nervous system depression. There is then a latent period lasting approximately 12-24 hours, depending, in part, on the methanol dose ingested, following which an uncompensated metabolic acidosis develops and visualfunction becomes impaired, ranging from blurred vision and altered visual fields to complete blindness.

MANAGEMENT

For the patient presenting with ophthalmologic abnormalities or significant acidosis, the acidosis should be corrected with intravenous sodium bicarbonate, the further generation of toxic metabolite should be blocked by the administration of fomepizole or ethanol and formic acid metabolism should be enhanced by the administration of intravenous folinic acid. Hemodialysis may also be required to correct severe metabolic abnormalities and to enhance methanol and formate elimination. For the methanol poisoned patient without evidence of clinical toxicity, the first priority is to inhibit methanol metabolism with intravenous ethanol orfomepizole. Although there are no clinical outcome data confirming the superiority of either of these antidotes over the other, there are significant disadvantages associated with ethanol. These include complex dosing, difficulties with maintaining therapeutic concentrations, the need for more comprehensive clinical and laboratory monitoring, and more adverse effects. Thus fomepizole is very attractive, however, it has a relatively high acquisition cost.

CONCLUSION

The management of methanol poisoning includes standard supportive care, the correction of metabolic acidosis, the administration of folinic acid, the provision of an antidote to inhibit the metabolism of methanol to formate, and selective hemodialysis to correct severe metabolic abnormalities and to enhance methanol and formate elimination. Although both ethanol and fomepizole are effective, fomepizole is the preferred antidote for methanol poisoning.

Extracorporeal therapies for acute intoxications

Intoxications frequently perturb acid-base and electrolyte status, intravascular volume, and renal function. In selected cases, extracorporeal techniques effectively restore homeostasis and augment intoxicant removal. The use of 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, is a new and effective treatment for patients exposed to toxic alcohols. In this section, practical approaches to commonly encountered intoxicants and the use of extracorporeal techniques are critically reviewed.

Outcomes of Severe Methanol Intoxication Treated with Hemodialysis: Report of Seven Cases and Review of Literature

To identify factors associated with the outcome of severe methanol intoxication treated with hemodialysis, we analyzed the clinical course of 7 patients admitted with serum methanol level higher than 50 mg/dL, and therefore requiring hemodialysis. Four patients (group A) had adverse outcomes (1 death, 3 severe neurological deficits and/or blindness) and 3 patients (group B) had no adverse outcomes. Compared to group B, group A appeared to have a longer delay between ingestion of methanol and arrival at the emergency department (ED), a longer wait in the ED until ethanol infusion was started (3.6 ± 2.7 vs 1.3 ± 0.9 hr, p < 0.05), and, on admission, higher serum methanol (504 ± 219 vs 321 ± 228 mg/dL, p < 0.05), higher serum osmolality (460.5 ± 98.2 vs 397.6 ± 52.3 mOsm/kg, p < 0.05), higher serum osmolal gap (162.6 ± 76.7 vs 105.6 ± 52.9 mOsm/kg, p < 0.05), lower arterial pH (6.86 ± 0.08 vs 7.38 ± 0.16, p < 0.01), lower serum bicarbonate (4.6 ± 1.6 vs 19.9 ± 5.7 mmol/L, p < 0.01), and higher serum anion gap (36.5 ± 1.3 vs 14.3 ± 6.7 mEq/L, p < 0.01). Delay in the ED until hemodialysis was started did not differ (group A 6.4 ± 2.6 hr, group B 5.3 ± 3.5 hr), while duration of hemodialysis until serum methanol levels became permanently undetectable was longer in group A (15.0 ± 0.5 vs 8.4 ± 4.4 hr, p < 0.01). The ingested dose of methanol and the delay between ingestion and initiation of therapy to block methanol metabolism (ethanol infusion) and remove methanol from the body (hemodialysis) appear to be the critical factors influencing the outcome of methanol intoxication. Early diagnosis and initiation of treatment before substantial parts of the ingested methanol have been metabolized are of paramount importance in ensuring a favorable outcome.