Acute Methanol Poisoning: Prevalence and Predisposing Factors of Haemorrhagic and Non-Haemorrhagic Brain Lesions

Intracerebral hemorrhage in methanol toxicity patients during COVID-19 pandemic: case report and review of literature

PURPOSE

The aim of this study is to examine the clinical and imaging manifestations of methanol toxicity during the COVID-19 pandemic, as well as to review existing studies on this topic. The most common cause of methanol intoxication is methanol-adulterated liquor. The primary metabolite of methanol, formic acid, is responsible for pathological changes. Symptoms typically present within 6-24 h of consumption and can include visual disturbances, acute neurological symptoms, and gastrointestinal issues. During the initial year of the COVID-19 pandemic, methanol poisoning cases increased significantly.

METHODS

In this study, We present six different patients with methanol intoxication and their clinical and imaging features.

RESULTS

In the literature review, the most common clinical presentation was loss of consciousness and obtundation and the other was vision loss. CT scan findings showed bilateral putaminal necrosis and hemorrhage in 55% of methanol toxicity patients.

CONCLUSION

Methanol intoxication, causing bilateral putaminal involvement and a 50% mortality rate in intracerebral hemorrhage patients, warrants urgent toxicological analysis due to potential putaminal hemorrhage.

Uncommon Causes of Nontraumatic Intracerebral Hemorrhage

Nontraumatic intracerebral hemorrhage is an important health issue. Although common causes such as hypertension and cerebral amyloid angiopathy predominantly affect the elderly, there exists a spectrum of uncommon etiologies that contribute to the overall incidence of intracerebral hemorrhage. The identification of these rare causes is essential for targeted clinical management, informed prognostication, and strategic secondary prevention where relevant. This topical review explores the uncommon intracerebral hemorrhage causes and provides practical clues for their clinical and imaging identification. By expanding the clinician's differential diagnosis, this review aims to bridge the gap between standard intracerebral hemorrhage classification systems and the nuanced reality of clinical practice.

An Autopsy Case Report of Homicide by Methanol Intoxication With Pinkish Bilateral Putamina

ABSTRACT

Many deaths caused by methanol occur as a result of intentional suicide attempts or accidental ingestion, and several investigators have quantified methanol and formic acid in blood and organs. However, to the best of our knowledge, no reports have described regional differences in the concentration of methanol in the brain. A man in his 50s drank alcohol that had been deliberately contaminated with methanol by his wife, and he died of multiple-organ failure after 4 days of intensive medical treatment including hemodialysis. On medicolegal autopsy, cross sections of the brain showed scattered petechial hemorrhage in the brain stem and microscopic hemorrhage with congestion in the bilateral putamina, which showed pinkish discoloration. The concentrations of methanol, formic acid, and ethanol in autopsy samples were measured by headspace gas chromatography, revealing relatively high concentrations of residual methanol and formic acid in the brain (especially in the basal ganglia), although methanol had been eliminated from the blood. Even after 4 days of medical treatment, postmortem toxicological analysis of the brain tissue indicated methanol ingestion. The accumulation of formic acid and the consequent local metabolic acidosis may cause brain lesions.

Acute and chronic blood serum proteome changes in patients with methanol poisoning

Twenty-four blood serum samples from patients with acute methanol poisoning (M) from the mass methanol poisoning outbreak in the Czech Republic in 2012 were compared with 46 patient samples taken four years after poisoning (S) (overlap of 10 people with group M) and with a control group (C) of 24 samples of patients with a similar proportion of chronic alcohol abuse. When comparing any two groups, tens to hundreds of proteins with a significant change in concentration were identified. Fifteen proteins showed significant changes when compared between any two groups. The group with acute methanol poisoning showed significant changes in protein concentrations for at least 64 proteins compared to the other groups. Among the most important identified proteins closely related to intoxication are mainly those involved in blood coagulation, metabolism of vitamin A (increased retinol-binding protein), immune response (e.g., increased complement factor I, complement factors C3 and C5), and lipid transport (increased apolipoprotein A I, apolipoprotein A II, adiponectin). For blood coagulation, the most affected proteins with significant changes in the methanol poisoning group were von Willebrand factor, carboxypeptidase N, alpha-2-antiplasmin (all increased), inter-alpha-trypsin inhibitor heavy chain H4, kininogen-1, plasma serine protease inhibitor, plasminogen (all decreased). However, heparin administration used for the methanol poisoning group could have interfered with some of the changes in their concentrations. Data are available via ProteomeXchange with the identifier PXD035726.

Late hemorrhagic transformation of brain lesions in case with methanol intoxication

Methanol intoxication can be occurred as accidental or suicidal ingestion or intentional ingestion through abuse. Formic acid is the primary toxic metabolite which causes high anion gap metabolic acidosis and end-organ damage in the human body. Here we presented a 46-year-old man who loss of consciousness on the 23rd day of hospitalization and his cranial computed tomography revealed bilateral subcortical hemorrhages. This case indicates us an example of late appearance of hemorrhagic transformation in methanol intoxication.

Formic acid induces hypertension-related hemorrhage in hSSAOTG in mice and human

Hypertension is a confirmed risk factor for cerebral hemorrhage in humans. Which endogenous factor directly induces hypertension-related hemorrhage is unclear. In this study, 42 hemorrhagic patients with hypertension and hyperlipidemia and 42 age-matched healthy controls were enrolled. The contents of serum semicarbazide-sensitive amine oxidase (SSAO) and formic acid (FC, FC is a final product of SSAO through the oxidation of endogenous formaldehyde, which results from the enzymatic oxidative deamination of the SSAO substrate, methylamine) were examined in the patients after stroke. Hemorrhagic areas were quantified by computer tomography. In the animal study, hemorrhagic degree was assessed by hemotoxylin & eosin or tissue hemoglobin kits. The relationship between FC and blood pressure/hemorrhagic degree was examined in wild-type mice and hSSAO^TG mice fed with high-fat diets or high-fat and -salt diets. The results showed that the levels of serum FC were positively correlated with blood pressure and hemorrhagic areas in hemorrhagic patients. Transfection of microRNA-134 could enhance SSAO expression in human vascular smooth muscle cells. Consistently, after treatment with high-fat and -salt diets, hSSAO^TG mice exhibited higher levels of miR134 and FC, higher blood pressure, and more severe hemorrhage than wild-type mice. Interestingly, folic acid reduced hypertension and hemorrhage in hSSAO^TG mice fed with high-fat diets. These findings suggest that FC is a crucial endogenous factor for hypertension and hemorrhage.

Acute methanol poisoning with bilateral diffuse cerebral hemorrhage: A case report

BACKGROUND

Acute methanol poisoning (AMP) is a systemic disease that mainly affects the central nervous system and is characterized by ocular damage and metabolic acidosis. If appropriate treatments are inadequate or delayed, the mortality can exceed 40%. As the most serious complication, cerebral hemorrhage is rare with reported prevalence of 7%-19%.

CASE SUMMARY

A 62-year-old man drank liquor mixed with 45% methanol and 35% alcohol. His vision blurred 10 h later and he fell into coma in another 9 h. Serum toxicological tests were performed immediately, and continuous renal replacement therapy (CRRT) was carried out as the lactic acid exceeded 15 mmol/L and blood pH was 6.78. In addition, the toxicological report revealed 1300.5 μg/mL of methanol in serum and 1500.2 μg/mL in urine. After 59 h of CRRT, the methanol level decreased to 126.0 μg/mL in serum and 151.0 μg/mL in urine. However, the patient was still unconscious and his pupillary light reflex was slow. Computed tomography showed hemorrhage in the left putamen. After 16 d of life support treatment, putamen hemorrhage developed into diffuse symmetric intracerebral hemorrhage. In the end, his family gave up and the patient was discharged, and died in a local hospital.

CONCLUSION

Cerebral hemorrhage requires constant vigilance during the full course of treatment for severe cases of AMP.

Biochemical mechanism underlying the pathogenesis of diabetic retinopathy and other diabetic complications in humans: the methanol-formaldehyde-formic acid hypothesis

Hyperglycemia in diabetic patients is associated with abnormally-elevated cellular glucose levels. It is hypothesized that increased cellular glucose will lead to increased formation of endogenous methanol and/or formaldehyde, both of which are then metabolically converted to formic acid. These one-carbon metabolites are known to be present naturally in humans, and their levels are increased under diabetic conditions. Mechanistically, while formaldehyde is a cross-linking agent capable of causing extensive cytotoxicity, formic acid is an inhibitor of mitochondrial cytochrome oxidase, capable of inducing histotoxic hypoxia, ATP deficiency and cytotoxicity. Chronic increase in the production and accumulation of these toxic one-carbon metabolites in diabetic patients can drive the pathogenesis of ocular as well as other diabetic complications. This hypothesis is supported by a large body of experimental and clinical observations scattered in the literature. For instance, methanol is known to have organ- and species-selective toxicities, including the characteristic ocular lesions commonly seen in humans and non-human primates, but not in rodents. Similarly, some of the diabetic complications (such as ocular lesions) also have a characteristic species-selective pattern, closely resembling methanol intoxication. Moreover, while alcohol consumption or combined use of folic acid plus vitamin B is beneficial for mitigating acute methanol toxicity in humans, their use also improves the outcomes of diabetic complications. In addition, there is also a large body of evidence from biochemical and cellular studies. Together, there is considerable experimental support for the proposed hypothesis that increased metabolic formation of toxic one-carbon metabolites in diabetic patients contributes importantly to the development of various clinical complications.

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.

Estimation of long-term costs of postacute care in survivors of the methanol poisoning outbreak

OBJECTIVES

To fill the existing research gap related to long-term costs of postacute care in methanol poisoning survivors, healthcare cost for 6 years after the outbreak has been modelled and estimated.

DESIGN

In a prospective longitudinal cohort study, data collected from 55 survivors of the Czech methanol mass poisoning outbreak in 2012 were collected in four rounds (5 months, then 2, 4 and 6 years after the discharge) in the General University Hospital in Prague according to the same predefined study protocol. The collected data were used to inform the cost model.

SETTING AND PARTICIPANTS

All 83 patients discharged from a hospital poisoning treatment after the 2012 methanol outbreak were informed about the study and invited to participate. Fifty-five patients (66%) gave their written informed consent and were followed until their death or the last follow-up 6 years later. The costs were modelled from the Czech healthcare service (general health insurance) perspective.

MAIN OUTCOME MEASURES

Long-term national budget impact of the methanol poisoning outbreak, frequencies of sequelae and their average costs.

RESULTS

The postacute cost analysis concentrated on visual and neurological sequelae that were shown to be dominant. Collected data were used to create process maps portraying gradual changes in long-term sequelae over time. Individual process maps were created for the central nervous system, peripheral nervous system, sequelae detected during eye examinations and sequelae concerning the visual evoked potentials. Based on the process maps the costs of the postacute outpatient care were estimated.

CONCLUSIONS

In 2013-2019 the highest costs per patient related to postacute care were found in the first year; the average costs decreased afterwards, and remained almost constant for the rest of the studied period of time. These costs per patient ranged from CZK4142 in 2013 to CZK1845 in 2018, when they raised to CZK2519 in 2019 again.

Methanol poisoning in Turkey: Two outbreaks, a single center experience

OBJECTIVES

Methanol poisoning is still one of the major causes of mortality due to intoxication because of the challenging diagnosis and late hospital admissions. We aimed to evaluate epidemiological data, clinical characteristics, laboratory findings, treatment protocols, and prognosis of patients in a tertiary hospital in two different methanol outbreaks occurring in a three-year interval.

METHODS

The study was planned as a single-center and retrospective observational case series study. Patients ≥18 years of age who were admitted to the hospital between 1 September 2016 and 1 September 2019 and diagnosed with methanol poisoning were included in the study.

RESULTS

Sixty-seven patients whose data were sufficient and accessible were included in the study. Thirty-five (52.2%) patients were discharged without sequelae, 14 (20.9%) patients were discharged with sequelae (both central nervous system sequelae and visual sequelae in 3 patients, only visual sequelae in 11 patients) and 18 (26.9%) patients died. High anion gap (AG) metabolic acidosis (pH < 7.07, AG > 26.7), low Glasgow Coma Score, and increased lactate (lactate > 2.55 mmol/L) levels were found to be associated with poor outcome. Folate use in treatment did not have a statistically significant effect (p = 0.087) on the prevention of visual sequelae development, but it had a statistically significant effect on mortality (p = 0.041).

CONCLUSIONS

State of consciousness and the severity of metabolic acidosis were significant parameters associated with mortality. In addition to antidote and elimination therapies, given the benefit on mortality and low risk of adverse events, folate therapy should be considered for all patients with significant toxic methanol exposures.

Inpatient Burden and Mortality of Methanol Intoxication in the United States

BACKGROUND

This study aimed to assess inpatient prevalence, characteristics, outcomes, and resource utilization of hospitalization for methanol intoxication in the United States.

MATERIALS AND METHODS

A total of 603 hospitalized patients with a primary diagnosis of methanol intoxication from 2003 to 2014 were identified in the National Inpatient Sample database. The inpatient prevalence, clinical characteristics, treatments, outcomes, resource utilization, were investigated. Multivariable logistic regression was performed to identify factors independently associated with in-hospital mortality.

RESULTS

The overall inpatient prevalence of methanol intoxication among hospitalized patients was 6.4 cases per 1,000,000 admissions in the United States. The mean age was 38±18 (range 0-86) years. 44% used methanol for suicidal attempts. 20% of admissions required mechanical ventilation, and 40% required renal replacement therapy. The three most common complications were metabolic acidosis (44%), hypokalemia (18%), and visual impairment or optic neuritis (8%). The three most common end-organ failures were renal failure (22%), respiratory failure (21%), and neurological failure (17%). 6.5% died in the hospital. Factors associated with increased in-hospital mortality included alcohol drinking, hypernatremia, renal failure, respiratory failure, circulatory failure, and neurological failure. The mean length of hospital stay was 4.0 days. The mean hospitalization cost per patient was $43,222 CONCLUSION: The inpatient prevalence of methanol intoxication in the United States was 6.4 cases per 1,000,000 admissions. The risk of in-hospital mortality mainly depended on the number of end-organ failures.

Efficiency of 123I-ioflupane SPECT as the marker of basal ganglia damage in acute methanol poisoning: 6-year prospective study

CONTEXT

Investigate whether ¹²³I-ioflupane SPECT (DaT SPECT) has the potential as a marker of basal ganglia damage in acute methanol poisoning.

METHODS

Prospective, single-centre, cohort study of patients with confirmed methanol poisoning was conducted. DaT SPECT was performed twice with semi-quantification using DaTQUANT^TM and MRI-based volumetry was calculated. Specific binding ratios (SBR) of striatum, caudate nucleus, and putamen were correlated with laboratory parameters of outcome, volumetric data, and retinal nerve fibres layer (RNFL) thickness measurements.

RESULTS

Forty-two patients (mean age 46.3 ± 4.2 years; 8 females), including 15 with MRI-detected putamen lesions (group I) and 27 patients with intact putamen (group II), underwent DaT SPECT. Volumetry was calculated in 35 of the patients assessed. SBR values for the left putamen correlated with putamen volume (r = 0.665; p < 0.001). Decreased bilateral SBR values were determined for the striatum and the putamen, but not for the nucleus caudate, in group I (p < 0.05). Significant correlation was observed between the SBR of the posterior putamen and arterial blood pH (r = 0.574; p < 0.001) and other toxicological parameters of severity of poisoning/outcome including serum lactate, glucose, and creatinine concentrations (p < 0.05). The SBR of the posterior putamen positively correlated with the global RNFL thickness (p < 0.05). ROC analysis demonstrated a significant discriminatory ability of SBR of the posterior putamen with AUC = 0.753 (95%CI 0.604-0.902; p = 0.007). The multivariate regression model demonstrated that arterial blood pH, age, and gender were the most significant factors associated with SBR of the posterior putamen.

CONCLUSION

DaT SPECT demonstrates significant potential for the diagnosis of methanol-induced basal ganglia damage.

Bilateral lesions of the basal ganglia and thalami (central grey matter)-pictorial review

The basal ganglia and thalami are paired deep grey matter structures with extensive metabolic activity that renders them susceptible to injury by various diseases. Most pathological processes lead to bilateral lesions, which may be symmetric or asymmetric, frequently showing characteristic patterns on imaging studies. In this comprehensive pictorial review, the most common and/or typical genetic, acquired metabolic/toxic, infectious, inflammatory, vascular and neoplastic pathologies affecting the central grey matter are subdivided according to the preferential location of the lesions: in the basal ganglia, in the thalami or both. The characteristic imaging findings are described with emphasis on the differential diagnosis and clinical context.

MRI-based brain volumetry and retinal optical coherence tomography as the biomarkers of outcome in acute methanol poisoning

BACKGROUND

Basal ganglia lesions are typical findings on magnetic resonance imaging (MRI) of the brain in survivors of acute methanol poisoning. However, no data are available on the association between the magnitude of damaged brain regions, serum concentrations of markers of acute methanol toxicity, oxidative stress, neuroinflammation, and the rate of retinal nerve ganglion cell loss.

OBJECTIVES

To investigate the association between MRI-based volumetry of the basal ganglia, retinal nerve fibre layer (RNFL) thickness and prognostic laboratory markers of outcomes in acute methanol poisoning.

METHODS

MRI-based volumetry of putamen, nucleus caudatus and globus pallidus was performed and compared with laboratory parameters of severity of poisoning and acute serum markers of oxidative damage of lipids (8-isoprostan, MDA, HHE, HNE), nucleic acids (8-OHdG, 8-OHG, 5-OHMU), proteins (o-Thyr, NO-Thyr, Cl-Thyr) and leukotrienes (LTC4, LTD4, LTE4, LTB4), as well as with the results of RNFL measurements by optic coherence tomography (OCT) in 16 patients with acute methanol poisoning (Group I) and in 28 survivors of poisoning two years after discharge with the same markers measured within the follow-up examination (Group II). The control group consisted of 28 healthy subjects without methanol poisoning.

RESULTS

The survivors of acute methanol poisoning had significantly lower volumes of basal ganglia than the controls. The patients with MRI signs of methanol-induced toxic brain damage had significantly lower volumes of basal ganglia than those without these signs. A positive correlation was found between the volume of putamen and arterial blood pH on admission (r = 0.45; p = 0.02 and r = 0.44; p = 0.02 for left and right putamen, correspondingly). A negative correlation was present between the volumes of putamen and acute serum lactate (r = -0.63; p < 0.001 and r = -0.59; p = 0.01), creatinine (r = -0.53; p = 0.01 and r = -0.47; p = 0.01) and glucose (r = -0.55; p < 0.001 and r = -0.50; p = 0.01) concentrations. The volume of basal ganglia positively correlated with acute concentrations of markers of lipoperoxidation (8-isoprostan: r = 0.61; p < 0.05 and r = 0.59; p < 0.05 for left and right putamen, correspondingly) and inflammation (leukotriene LTB4: r = 0.61; p < 0.05 and r = 0.61; p < 0.05 for left and right putamen, correspondingly). The higher the volume of the basal ganglia, the higher the thickness of the RNFL, with the strongest positive association between global RNFL and the volume of putamen bilaterally (all p < 0.01). In the follow-up markers of oxidative stress and inflammation, only o-Thyr concentration negatively correlated with the volume of putamen bilaterally (r = -0.39; p < 0.05 and r = -0.37; p < 0.05 for left and right putamen, correspondingly).

CONCLUSION

In survivors of acute methanol poisoning with signs of toxic brain damage, the magnitude of affected areas correlated with acute parameters of severity of poisoning, markers of oxidative stress and neuroinflammation. There was a positive association between the basal ganglia volume and the thickness of RNFL, making OCT an important screening test and MRI-based volumetry the confirmative diagnostic method for the detection of CNS sequelae of methanol poisoning.

Methanol induced stroke: report of cases occurring simultaneously in two biological brothers

Methanol bears semblance to ethanol in smell and taste, thus, individuals who indulge in alcohol may fall back on it in societies where alcohol consumption is illegal or difficult to come by despite the life-threatening neurologic sequelae of methanol toxicity. Stroke is an uncommon outcome of methanol poisoning. We presented two cases of methanol-induced infarctive and hemorrhagic stroke in biological brothers who were simultaneously involved in an illicit ingestion of methanol. One of them developed infarctive stroke while the other had infarctive stroke with hemorrhagic transformation. We have highlighted the differences and similarity in the course of their illnesses.

Health-related quality of life determinants in survivors of a mass methanol poisoning outbreak: six-year prospective cohort study

Purpose: The effect of acute methanol poisoning on the follow-up quality of life of survivors in mass poisoning outbreaks is not known. The objective of this is to study the impact of visual and central nervous system (CNS) sequelae of methanol poisoning on long-term health-related quality of life (QoL) of survivors, its clinical determinants, and dynamics.Materials and methods: A total of 54 patients with confirmed methanol poisoning (mean age 46.7 ± 13.4 years, 9 females) were examined consequently three times within six-year prospective cohort study and compared to 23 controls with the history of chronic alcohol abuse. The following tests were performed: SF-36 QoL questionnaire, visual evoked potentials (VEP) of optic nerve, ocular examination with retinal nerve fiber layer (RNFL) thickness measurement, brain magnetic resonance imaging (MRI), and biochemical and toxicological tests.Results: Acute methanol poisoning led to significant decrease in physical component summary (PCS) compared to PCS of age-adjusted controls (mean score with SD 46.8 ± 11.0 versus 52.3 ± 9.4 points; p = .003). In 17/40 (42.5%) patients with three rounds of examination, signs of severe disability (≤30 points in at least one score) were present six years after discharge, with negative dynamics of PCS score during the observation period. The patients with abnormal RNFL thickness had lower PCS (mean difference 10.5 points; 95%CI 3.5-17.5, p = .004) and mental component summary score (9.5 points; 95%CI 1.9-17.1, p = .015) compared to the patients with normal RNFL. Signs of physical and mental adaptation to long-term visual sequelae were registered with gradual reduction of difference in most of physical and mental components scores compared to the patients with normal RNFL during six years of observation. Signs of hemorrhagic brain lesions were associated with permanent decrease of PCS score (mean difference 7.4 points; 95%CI 0.6-14.0; p = .033), bodily pain (8.7 points; 95%CI 1.6-17.6; p = .018), and social functioning (8.2 points; 95%CI 3.0-17.4; p = .005) six years after discharge. No effect of type of antidote (fomepizole versus ethanol) and extracorporeal enhanced elimination modality (intermittent hemodialysis versus continuous renal replacement therapy) applied in hospital on long-term QoL was found (all p > .05).Conclusion: Acute methanol poisoning was associated with a significant decrease of health-related quality of life of survivors persisting for at least six years after discharge. The more pronounced decrease in QoL scores was observed in the patients with hemorrhagic brain lesions and visual sequelae of poisoning with abnormal RNFL thickness.

Single center experience of managing methanol poisoning in the hilly state of Uttarakhand: A cross sectional study

Background

In this article, we describe our experience in managing one of the worst tragedies of an outbreak of methanol poisoning in the state of Uttarakhand in February 2019. It was reported that more than 100 people of Uttarakhand and neighboring districts of Uttar Pradesh succumbed to death after consuming this toxic alcohol laced with methanol.

Materials and Methods

Demographic, clinical, and biochemical data were collected retrospectively from the hospital record section of the tertiary care hospital in the state of Uttarakhand.

Results

Ninety-three patients of methanol poisoning were attended by the emergency medicine department of our hospital. The mean age of the patients was 38.9 ± 10.3 years. Majority of the patients were males (92/93). The most common clinical symptoms were gastrointestinal (56; 60.2%) followed by neurological (21; 22.6%) and respiratory (18; 19.3%). Most of the patients presented within 12-24 h after consumption of methanol. The mean of latent time of presentation was 4.8 ± 2.6 h. The mean values of pH, bicarbonate levels, lactate, and base deficit were 7.13 ± 0.6, 12.3 ± 6.4, 2.6 ± 0.8, and 15.6 ± 3.8 mmol/l, respectively. Acute kidney injury (26; 27.9%), blurring of vision (9; 9.6%), and sepsis (6, 6.4%) were common complications. Seven patients (7.5%) succumbed to death. Intensive alkali therapy was the main modality of treatment. Ethanol therapy was useful in patients resistant to alkali therapy. Sixteen (17.2%) patients with acute methanol poisoning were dialyzed once.

Conclusion

Patients with acute methanol poisoning have varied presentations. Gastrointestinal symptoms are the most common presentation. Such outbreaks account for the heavy toll of mortality and morbidity in the society. Prompt diagnosis and a protocol based treatment can have a significant impact on the outcome of these patients. Thus, public health warning should be immediately issued with initial presentation of the casualties.

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.

The impact of co-morbidities on a 6-year survival after methanol mass poisoning outbreak: possible role of metabolic formaldehyde

Context: The influence of co-morbid conditions on the outcome of acute methanol poisoning in mass poisoning outbreaks is not known.Objective: The objective of this is to study the impact of burden of co-morbidities, complications, and methanol-induced brain lesions on hospital, follow-up, and total mortality.Methods: All patients hospitalized with methanol poisoning during a mass poisoning outbreak were followed in a prospective cohort study until death or final follow-up after 6 years. The age-adjusted Charlson co-morbidity index (ACCI) score was calculated for each patient. A multivariate Cox regression model was used to calculate the adjusted hazards ratio (HR) for death. The survival was modeled using the Kaplan-Meier method.Results: Of 108 patients (mean age with SD 50.9 ± 2.6 years), 24 (54.4 ± 5.9 years) died during hospitalization (mean survival with SD 8 ± 4 days) and 84 (49.9 ± 3.0 years; p = .159) were discharged, including 27 with methanol-induced brain lesions. Of the discharged patients, 15 (56.3 ± 6.8 years) died during the follow-up (mean survival 37 ± 11 months) and 69 (48.5 ± 3.3 years; p = .044) survived. The hospital mortality was 22%, the follow-up mortality was 18%; the total mortality was 36%. Cardiac/respiratory arrest, acute respiratory failure, multiorgan failure syndrome, and arterial hypotension increased the HR for hospital and total (but not follow-up) mortality after adjustment for age, sex, and arterial pH (all p < .05). All patients who died in the hospital had at least one complication. A higher ACCI score was associated with greater total mortality (HR 1.22; 1.00-1.48 95% CI; p = .046). Of those who died, 35 (90%) had a moderate-to-high ACCI. The Kaplan-Meier curve demonstrated that patients with a high ACCI had greater follow-up mortality compared to ones with low (p = .027) or moderate (p = .020) scores. For the patients who died during follow-up, cancers of different localizations were responsible for 7/15 (47%) of the deaths.Conclusions: The character and number of complications affected hospital but not follow-up mortality, while the burden of co-morbidities affected follow-up mortality. Methanol-induced brain lesions did not affect follow-up mortality. Relatively high cancer mortality rate may be associated with acute exposure to metabolic formaldehyde produced by methanol oxidation.

Clinical and genetic determinants of chronic visual pathway changes after methanol - induced optic neuropathy: four-year follow-up study

CONTEXT

Methanol poisoning induces acute optic neuropathy with possible long-term visual damage.

OBJECTIVE

To study the dynamics and key determinants of visual pathway functional changes during 4 years after acute methanol poisoning.

METHODS

A total of 42 patients with confirmed methanol poisoning (mean age 45.7 ± 4.4 years) were examined 4.9 ± 0.6, 25.0 ± 0.6, and 49.9 ± 0.5 months after discharge. The following tests were performed: visual evoked potential (VEP), retinal nerve fiber layer (RNFL) measurement, brain magnetic resonance imaging (MRI), complete ocular examination, biochemical tests, and apolipoprotein E (ApoE) genotyping.

RESULTS

Abnormal VEP P1 latency was registered in 18/42 right eyes (OD) and 21/42 left eyes (OS), abnormal N1P1 amplitude in 10/42 OD and OS. Mean P1 latency shortening during the follow-up was 15.0 ± 2.0 ms for 36/42 (86%) OD and 14.9 ± 2.4 ms for 35/42 (83%) OS, with maximum shortening up to 35.0 ms. No significant change of mean N1P1 amplitude was registered during follow-up. A further decrease in N1P1 amplitude ≥1.0 mcV in at least one eye was observed in 17 of 36 patients (47%) with measurable amplitude (mean decrease -1.11 ± 0.83 (OD)/-2.37 ± 0.66 (OS) mcV versus -0.06 ± 0.56 (OD)/-0.83 ± 0.64 (OS) mcV in the study population; both p < .001). ApoE4 allele carriers had lower global and temporal RNFL thickness and longer initial P1 latency compared to the non-carriers (all p < .05). The odds ratio for abnormal visual function was 8.92 (3.00-36.50; 95%CI) for ApoE4 allele carriers (p < .001). The presence of ApoE4 allele was further associated with brain necrotic lesions (r = 0.384; p = .013) and brain hemorrhages (r = 0.395; p = .011).

CONCLUSIONS

Improvement of optic nerve conductivity occurred in more than 80% of patients, but evoked potential amplitude tended to decrease during the 4 years of observation. ApoE4 allele carriers demonstrated lower RNFL thickness, longer P1 latency, and more frequent methanol-induced brain damage compared to non-carriers.

Progressive Chronic Retinal Axonal Loss Following Acute Methanol-induced Optic Neuropathy: Four-Year Prospective Cohort Study

PURPOSE

To study the dynamics and clinical determinants of chronic retinal nerve fiber layer thickness (RNFL) loss after methanol-induced optic neuropathy.

DESIGN

Prospective cohort study.

METHODS

All patients underwent complete ophthalmic evaluation including spectral-domain optical coherence tomography 3 times during 4 years of observation: 4.9 (±0.6), 25.0 (±0.6), and 49.9 (±0.5) months after discharge.

PARTICIPANTS

Eighty-four eyes of 42 survivors of methanol poisoning, mean age (standard deviation) of 45.7 (±4.4) years; and 82 eyes of 41 controls, mean age 44.0 (±4.2) years.

MAIN OUTCOME MEASURES

Global and temporal RNFL loss.

RESULTS

Abnormal RNFL thickness was registered in 13 of 42 (31%) survivors of methanol poisoning and chronic axonal loss in 10 of 42 (24%) patients. Significant decrease of global/temporal RNFL thickness during the observation period was found in the study population compared to the controls (P < .001). The risk estimate of chronic global RNFL loss for arterial blood pH < 7.3 at admission was 11.65 (95% confidence interval 1.91-71.12) after adjusting for age and sex. The patients with chronic axonal degeneration demonstrated progressive visual loss in 7 of 10 cases. The patients with abnormal RNFL thickness had magnetic resonance signs of brain damage in 10 of 13 vs 8 of 29 cases with normal RNFL thickness (P = .003). Signs of brain hemorrhages were present in 7 of 13 patients with abnormal RNFL thickness vs 5 of 29 cases with normal RNFL thickness (P = .015).

CONCLUSIONS

Methanol-induced optic neuropathy may lead to chronic retinal axonal loss during the following years. Arterial blood pH on admission is the strongest predictor of chronic RNFL thickness decrease. Chronic retinal neurodegeneration is associated with the progressive loss of visual functions and necrotic brain lesions.

Intermittent versus continuous renal replacement therapy in acute methanol poisoning: comparison of clinical effectiveness in mass poisoning outbreaks

BACKGROUND

Intermittent hemodialysis (IHD) is the modality of choice in the extracorporeal treatment (ECTR) of acute methanol poisoning. However, the comparative clinical effectiveness of intermittent versus continuous modalities (CRRT) is unknown. During an outbreak of mass methanol poisoning, we therefore studied the effect of IHD versus CRRT on mortality and the prevalence of visual/central nervous system (CNS) sequelae in survivors.

METHODS

The study was designed as prospective observational cohort study. Patients hospitalized with a diagnosis of acute methanol poisoning were identified for the study. Exploratory factor analysis and multivariate logistic regression were applied to determine the effect of ECTR modality on the outcome.

RESULTS

Data were obtained from 41 patients treated with IHD and 40 patients with CRRT. The follow-up time in survivors was two years. Both groups of patients were comparable by age, time to presentation, laboratory data, clinical features, and other treatment applied. The CRRT group was more acidemic (arterial blood pH 6.96 ± 0.08 vs. 7.17 ± 0.07; p < 0.001) and more severely poisoned (25/40 vs. 9/41 patients with Glasgow Coma Scale (GCS) ≤ 8; p < 0.001). The median intensive care unit length of stay (4 (range 1-16) days vs. 4 (1-22) days; p = 0.703) and the number of patients with complications during the treatment (11/41 vs. 13/40 patients; p = 0.576) did not differ between the groups. The mortality was higher in the CRRT group (15/40 vs. 5/41; p = 0.008). The number of survivors without sequelae of poisoning was higher in the IHD group (23/41 vs. 10/40; p = 0.004). There was a significant association of ECTR modality with both mortality and the number of survivors with visual and CNS sequelae of poisoning, but this association was not present after adjustment for arterial blood pH and GCS on admission (all p > 0.05).

CONCLUSIONS

In spite of the faster correction of the acidosis and the quicker removal of the toxic metabolite in intermittent dialysis, we did not find significant differences in the treatment outcomes between the two groups after adjusting for the degree of acidemia and the severity of poisoning on admission. These findings support the strategy of "use what you have" in situations with large outbreaks and limited dialysis capacity.

Cognitive sequelae of methanol poisoning involve executive dysfunction and memory impairment in cross-sectional and long-term perspective

Methanol poisoning leads to lesions in the basal ganglia and subcortical white matter, as well as to demyelination and atrophy of the optic nerve. However, information regarding cognitive deficits in a large methanol sample is lacking. The principal aim of the present study was to identify the cognitive sequelae of methanol poisoning and their morphological correlates. A sample of 50 patients (METH; age 48 ± 13 years), 3-8 months after methanol poisoning, and 57 control subjects (CS; age 49 ± 13 years) were administered a neuropsychological battery. Forty-six patients were followed in 2 years' perspective. Patients additionally underwent 1.5T magnetic resonance imaging (MRI). Three biochemical and toxicological metabolic markers and a questionnaire regarding alcohol abuse facilitated the classification of 24 patients with methanol poisoning without alcohol abuse (METHna) and 22 patients with methanol poisoning and alcohol abuse (METHa). All groups were compared to a control group of similar size, and matched for age, education, premorbid intelligence level, global cognitive performance, and level of depressive symptoms. Using hierarchical multiple regression we found significant differences between METH and CS, especially in executive and memory domains. METHa showed a similar pattern of cognitive impairment with generally more severe executive dysfunction. Moreover, all METH patients with extensive involvement on brain MRI (lesions in ≥2 anatomical regions) had a more severe cognitive impairment. From a longitudinal perspective, we did not find any changes in their cognitive functioning after 2 years' follow-up. Our findings suggest that methanol poisoning is associated with executive dysfunction and explicit memory impairment, supposedly due to basal ganglia dysfunction and disruption of frontostriatal circuitry proportional to the number of brain lesions, and that these changes are persistent after 2 years' follow-up.

Intracranial Hemorrhage in Methanol Toxicity: Challenging the Probable Heparin Effect during Hemodialysis

Brain hemorrhages are rare complications of acute methanol poisoning. There is a debate on association of brain hemorrhage in methanol toxicity and application of systemic anticoagulation during hemodialysis (HD). A 70-year-old male presented to us with severe metabolic acidosis and a methanol level of 7.6 mg/dL. Ethanol and folinic acid were administered, and HD was performed. Brain computed tomography (CT) scan which was normal on presentation showed extensive bilateral subcortical supratentorial hypodensities on the 3^rd day after commencing the treatment. However, the next CT scan performed 2 weeks later revealed expanding hemorrhagic transformation in previous hypodensities. Hemorrhagic changes could not be explained by patient's coagulation profile on the 3^rd day. Anticoagulation agents such as heparin are used routinely during a dialysis session to prevent clot formation in dialysis circuits. This case is possibly questioning the role of heparin in hemorrhagic brain lesions of methanol intoxication.

Positive serum ethanol concentration on admission to hospital as the factor predictive of treatment outcome in acute methanol poisoning

ABSTRACT

Mass methanol poisonings present a serious problem for health systems worldwide, with poor outcome associated with delayed treatment. Positive pre-hospital serum ethanol concentration may have predictive value as the prognostic factor of the treatment outcome. We studied the effect of positive serum ethanol level on admission to hospital on survival in patients treated during the Czech methanol outbreak during 2012-2014. Cross-sectional cohort study was performed in 100 hospitalized patients with confirmed methanol poisoning. Pre-hospital ethanol was administered in 42 patients (by paramedic/medical staff to 30 patients and self-administered by 12 patients before admission); 58 patients did not receive pre-hospital ethanol. Forty-two patients had detectable serum ethanol concentration on admission to hospital [median 18.3 (IQR 6.6-32.2) mmol dm-3]. Pre-hospital ethanol administration by paramedic/medical staff had a significant effect on survival without visual and CNS sequelae when adjusted for arterial blood pH on admission (OR 8.73; 95 % CI 3.57-21.34; p < 0.001). No patients receiving pre-hospital ethanol died compared with 21 not receiving (p < 0.001). Positive serum ethanol concentration on admission to hospital was a predictor for survival without health sequelae when adjusted for arterial blood pH (OR 8.10; 95 % CI 2.85-23.02; p < 0.001). The probability of visual and CNS sequelae in survivors reduced with increasing serum ethanol concentration on admission.

GRAPHICAL ABSTRACT