Long-term renal and neurologic outcomes among survivors of diethylene glycol poisoning

Antidotes for poisoning by alcohols that form toxic metabolites

The alcohols methanol, ethylene glycol and diethylene glycol share many characteristics. The most important is that the compounds themselves are relatively nontoxic but are metabolized, initially by alcohol dehydrogenase, to various toxic intermediates. These compounds are readily available worldwide in commercial products as well as in homemade alcoholic beverages, both of which lead to most of the poisonings, from either unintentional or intentional ingestion. Although relatively infrequent, toxic alcohol poisonings do unfortunately occur in outbreaks and can result in severe morbidity and mortality. These poisonings have traditionally been treated with ethanol since it competes for the active site of alcohol dehydrogenase and decreases the formation of toxic metabolites. Although ethanol can be an effective antidote, there are substantial practical problems with its use. Therefore fomepizole, a potent competitive inhibitor of alcohol dehydrogenase, was developed for a hopefully better treatment for metabolically toxic alcohol poisonings. Fomepizole has few side effects and is easy to use in practice and it may obviate the need for haemodialysis in some, but not all, patients. Hence, fomepizole has largely replaced ethanol as the toxic alcohol antidote in many countries. Nevertheless, ethanol remains an important alternative because access to fomepizole can be limited, the cost may appear excessive or the physician may prefer ethanol due to experience.

Diglycolic acid inhibits succinate dehydrogenase activity, depletes mitochondrial membrane potential, and induces inflammation in an SH-SY5Y neuroblastoma model of neurotoxicity in vitro

Diethylene glycol is a toxic industrial solvent resulting in a well-defined toxidrome. Diglycolic acid (DGA) has been identified as the metabolite responsible for the nephrotoxicity and hepatotoxicity. These studies assess the mechanism of DGA-induced neurotoxicity, specifically addressing the known ability of DGA to chelate calcium (Ca²⁺) in solution and inhibit mitochondrial complex II. SH-SY5Y cells were seeded into 96-well plates to assess intracellular Ca²⁺ chelation, complex II activity, mitochondrial membrane potential (ΔΨm), ATP production, and release of inflammatory cytokines TNF-α and IL-1β with 2-, 4-, 6-, 24-, and 48-h DGA exposure. Peak Ca²⁺ chelation occurred at 4 h in cells treated with 6.25-50 mM DGA; however, effects were transient. Complex II activity was significantly decreased at all DGA concentrations tested, with 12.5 mM DGA causing 80% inhibition and 25 and 50 mM DGA causing 97 and 100% inhibition, respectively. Subsequently, 12.5-50 mM DGA concentrations significantly decreased ΔΨm at all time points. 50 mM DGA significantly increased release of TNF-α and IL-1β after 24 and 48 h with significantly decreased ATP production observed at the same time points and concentration. These studies demonstrate that the DGA-induced mechanism of SH-SY5Y cell death involves complex II inhibition leading to mitochondrial depolarization, and subsequent ATP depletion with accompanying inflammatory cytokine release. These results indicate a direct mechanism of DGA-induced neurotoxicity in vitro, similarly observed in other DEG-affected target organs.

Update on Toxic Neuropathies

Purpose of Review

Toxic neuropathies are an important preventable and treatable form of peripheral neuropathy. While many forms of toxic neuropathies have been recognized for decades, an updated review is provided to increase vigilant in this area of neurology. A literature review was conducted to gather recent information about toxic neuropathies, which included the causes, clinical findings, and treatment options in these conditions.

Recent Findings

Toxic neuropathies continue to cause significant morbidity throughout the world and the causative agents, particularly with regards to medications, do not appear to be diminishing. A wide variety of causes of toxic neuropathies exist, which include alcohol, industrial chemicals, biotoxins, and medications. Unfortunately, no breakthrough treatments have been developed and prevention and symptom management remain the standard of care.

Summary

A detailed medication, occupational and hobby exposure history is critical to identifying toxic neuropathies. Increased research is warranted to identify mechanisms of neurotoxic susceptibility and potential common pathomechanistic pathways for treatment across diverse toxic neuropathies.

Ethylene Glycol Intoxication Requiring ECMO Support

Ethylene glycol is commonly used in antifreeze, and ingestion of even a small amount can result in acute kidney injury, severe metabolic acidosis, and neurological injury. When cases are recognized early, treatment involves administration of alcohol dehydrogenase inhibitors to prevent conversion to toxic metabolites of glycolate, glyoxolate, and oxalate. In later presentations with more severe renal injury, hemodialysis may be required for clearance of toxic metabolites and supportive care for renal failure. We present the first reported case of severe ethylene glycol intoxication requiring support of extracorporeal membrane oxygenation (ECMO) due to refractory cardiopulmonary collapse.

Diethylene glycol and its metabolites induce cell death in SH-SY5Y neuronal cells in vitro

Diethylene glycol (DEG) intoxication results in metabolic acidosis, renal and hepatic dysfunction, and late-stage neurotoxicity. Though the renal and hepatic toxicity of DEG and its metabolites 2-hydroxyethoxyacetic acid (2-HEAA) and diglycolic acid (DGA) have been well characterized, the resultant neurotoxicity has not. SH-SY5Y neuroblastoma cells were incubated with all 3 compounds at increasing concentrations for 24, 48, or 120 h. At all 3 time points, 50 mmol/L DGA and 100 mmol/L DEG showed significant Annexin V and propidium iodide (PI) staining with additional concentrations showing similar staining patterns at 24 h (100 mmol/L DGA) and 48 h (50 mmol/L DEG, 100 mmol/L DGA). Only the 200 mmol/L 2-HEAA concentration induced SH-SY5Y cell death. Interestingly at 24 and 48 h, 100 mmol/L DEG induced significant increases in apoptotic cell death markers, which progressed to necrosis at 120 h. Similar to DEG, 50 mmol/L DGA induced significant increases in SH-SY5Y cell apoptosis and necrosis markers at both 24 and 48 h. As expected, high DGA concentrations (100 mmol/L) at 120 h induced significant SH-SY5Y cell necrosis with no apoptosis detected. However, at 120 h lower DGA concentrations (20 mmol/L) significantly increased oligonucleosome formation alone and in combination with 2-HEAA or DEG. Taken together, these results indicate that DGA and DEG at threshold concentrations induce neurotoxicity in SH-SY5Y cells.

Renal replacement therapy in the management of intoxications in children: recommendations from the Pediatric Continuous Renal Replacement Therapy (PCRRT) workgroup

BACKGROUND

Intentional or unintentional ingestions among children and adolescents are common. There are a number of ingestions amenable to renal replacement therapy (RRT).

METHODS

We systematically searched PubMed/Medline, Embase, and Cochrane databases for literature regarding drugs/intoxicants and treatment with RRT in pediatric populations. Two experts from the PCRRT (Pediatric Continuous Renal Replacement Therapy) workgroup assessed titles, abstracts, and full-text articles for extraction of data. The data from the literature search was shared with the PCRRT workgroup and two expert toxicologists, and expert panel recommendations were developed.

RESULTS AND CONCLUSIONS

We have presented the recommendations concerning the use of RRTs for treatment of intoxications with toxic alcohols, lithium, vancomycin, theophylline, barbiturates, metformin, carbamazepine, methotrexate, phenytoin, acetaminophen, salicylates, valproic acid, and aminoglycosides.

Outcomes after toxic alcohol poisoning: a systematic review protocol

BACKGROUND

Toxic alcohols have been implicated in accidental ingestions and intentional exposures. Recognition of toxic alcohol poisoning is challenging. The main treatment modalities include antidotes with alcohol dehydrogenase inhibitors and dialysis. Current guidelines exist for both methanol and ethylene glycol intoxication. However, treatment consensus related to other toxic alcohols is limited. Furthermore, uncertainties regarding thresholds for when to initiate antidotes and dialysis persist. As a consequence, variations exist in the interventions utilized for management of all toxic alcohol poisonings. To our knowledge, no prior systematic review of clinical outcomes of toxic alcohols exists. The objective of this study is to summarize existing evidence on short- and long-term outcomes of patients following toxic alcohol poisonings, including methanol, ethylene glycol, isopropanol, propylene glycol, and diethylene glycol.

METHODS

A literature search in PubMed, MEDLINE, and EMBASE will be performed based on pre-determined criteria. There will be no restrictions on publication dates or languages. The search will be supplemented by manual scan of bibliographies of eligible studies and gray literature assessment. Observational studies and clinical trials will be included in this review. Once eligible studies have been selected based on pre-specified criteria, two investigators will extract relevant data independently and perform quality assessment per validated tools. A pooled analysis of mortality and short- and long-term secondary outcomes will be performed. Pre-specified subgroup analyses will be performed according to the type of toxic alcohol intoxication, mode of renal replacement therapy, and medical interventions received. A meta-analysis will be performed if three or more studies with similar populations, type of toxic alcohol poisoning, and outcome measures, as well as adequate quality, are identified. This review will be reported according to the recommendations of the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) Statement.

DISCUSSION

This systematic review aims to synthesize current evidence in the short- and long-term outcomes of post-toxic alcohol poisoning. The results will enhance the understanding of patient morbidity and mortality after toxic alcohol poisoning, help inform uniform concrete management guideline development, identify gaps in the current state of knowledge, and provide evidence to help implement post-treatment follow-up.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018101955.

Comparison of diglycolic acid exposure to human proximal tubule cells in vitro and rat kidneys in vivo

•

Diglycolic acid (DGA) is an indirect food additive.

•

DGA was tested for renal cell toxicity in vitro using HK-2 cells.

•

Evaluation of toxicity included cellular and mitochondrial effects.

•

In vitro data are highly concordant with in vivo outcomes.

Diglycolic acid (DGA) is present in trace amounts in our food supply and is classified as an indirect food additive linked with the primary GRAS food additive carboxymethyl cellulose (CMC). Carboxymethyl starches are used as a filler/binder excipient in dietary supplement tablets and a thickening ingredient in many other processed foods. We sought to utilize the human proximal tubule HK-2 cell line as an in vitro cellular model system to evaluate its acute nephrotoxicity of DGA. We found that DGA was indeed toxic to HK-2 cells in all in vitro assays in our study, including a highly sensitive Luminex assay that measures levels of an in vitro biomarker of kidney-specific toxicity, Kidney Injury Molecule 1 (KIM-1). Interestingly, in vitro KIM-1 levels also correlated with in vivo KIM-1 levels in urine collected from rats treated with DGA by daily oral gavage. The use of in vitro and in vivo models towards understanding the effectiveness of an established in vitro system to predict in vivo outcomes would be particularly useful in rapidly screening compounds that are suspected to be unsafe to consumers. The merit of the HK-2 cell model in predicting human toxicity and accelerating the process of food toxicant screening would be especially important for regulatory purposes. Overall, our study not only revealed the value of HK-2 in vitro cell model for nephrotoxicity evaluation, but also uncovered some of the mechanistic aspects of the human proximal tubule injury that DGA may cause.

Chronic Kidney Disease in Panama: Results From the PREFREC Study and National Mortality Trends

Introduction

The magnitude of chronic kidney disease (CKD) in Panama has yet to be described. We investigated the association between sociodemographic and cardiovascular exposures with CKD in 2 Panamanian provinces. Further, we analyzed national trends of CKD mortality from 2001 to 2014.

Methods

Data were derived from Prevalencia de Factores de Riesgo de Enfermedad Cardiovascular (PREFREC [Survey on Risk Factors Associated With Cardiovascular Disease]), a cross-sectional study designed to analyze the prevalence of risk factors associated with cardiovascular disease. Biomarkers of kidney function were measured in 3590 participants. CKD was defined as an estimated glomerular filtration rate (eGFR) of <60 ml/min/1.73 m² and/or albuminuria ≥30 mg/g creatinine. Odds ratios (ORs) with 95% confidence intervals (CIs) for CKD were calculated using logistic regression. We calculated age-standardized CKD mortality rates in the country using the National Mortality Register. Annual percentage change and 95% CIs were estimated to evaluate the trends over time.

Results

The prevalence of CKD was 12% (reduced eGFR: 3.3%; albuminuria; 9.9%). CKD was associated with hypertension (OR: 1.8; 95% CI: 1.2−2.7), age 60 years or older (OR: 1.9; 95% CI: 1.2−2.9), and previous myocardial infarction (OR: 2.4; 95% CI: 1.0−5.7), whereas monthly family income was inversely associated with CKD (OR: 0.4; 95% CI: 0.1−0.9) (adjusted). A sustained increase in the trend of CKD mortality was observed from 2001 to 2006, followed by a decreasing trend in subsequent years. Coclé province had the highest adjusted mortality rate.

Discussion

CKD poses a significant health problem for Panama. Health inequalities and an increase of cardiometabolic risk factors warrant robust epidemiological surveillance, improved diagnosis, and treatment. Further national studies aimed to address geographical disparities are necessary.

Delayed autonomic neuropathy in a patient with diethylene glycol poisoning: a case report

Case

A 72-year-old man presented to our hospital after ingesting insecticide containing approximately 2 mL/kg diethylene glycol, which exceeded the lethal dose of 1 mL/kg. The patient recovered from critical symptoms on acute phase until day 3, but received artificial ventilation for muscle weakness secondary to sensorimotor neuropathy on days 11-54.

Outcome

Even after marked improvement from sensorimotor neuropathy, the patient continued to complain of orthostatic hypotension. Autonomic neuropathy was identified by positive result of a head-up tilt test, and reduction in coefficient of variation of R-R intervals and cardiac iodine-123-metaiodobenzylguanidine uptake for the assessment of cardiac sympathetic activity. The patient's symptoms fully recovered 2 years after the exposure to diethylene glycol.

Conclusion

This case shows the first report of delayed autonomic neuropathy after recovery from severe sensorimotor neuropathy, and suggests the importance of continuous monitoring for late-onset neurological complications.

Basal Ganglion Hemorrhage as Delayed Complication of Diethylene Glycol Ingestion

Diethylene glycol (DEG), an organic compound (HOCH2CH2)2O is a commonly used solvent. Mass poisoning outbreaks have been reported because of frequent contaminations. A PubMed search for diethylene resulted in 795 publications with 151 specifically discussing the toxicity. Of the 151 reported toxicity reviews/case reports, only 6 publications discussed the long-term neurological effects of diethylene toxicity. We report a fatal case of oral ingestion of DEG with complications from delayed toxicity. She died 7 days after the second admission. Autopsy disclosed a right basal ganglia hemorrhage within the brain and microscopic deposits of polarizable crystals into small cerebral blood vessels. Both kidneys illustrate tubular necrosis with scattered tubular deposition of polarizable calcium oxalate crystals. PubMed search leads to only 2 reported cases of basal ganglia hemorrhage (based on radiological findings) after ethylene glycol intoxication. Our case is the first reportable case of basal ganglia hemorrhage after DEG ingestion.

Antidotes for poisoning by alcohols that form toxic metabolites

The alcohols, methanol, ethylene glycol and diethylene glycol, have many features in common, the most important of which is the fact that the compounds themselves are relatively non-toxic but are metabolized, initially by alcohol dehydrogenase, to various toxic intermediates. These compounds are readily available worldwide in commercial products as well as in homemade alcoholic beverages, both of which lead to most of the poisoning cases, from either unintentional or intentional ingestion. Although relatively infrequent in overall occurrence, poisonings by metabolically-toxic alcohols do unfortunately occur in outbreaks and can result in severe morbidity and mortality. These poisonings have traditionally been treated with ethanol since it competes for the active site of alcohol dehydrogenase and decreases the formation of toxic metabolites. Although ethanol can be effective in these poisonings, there are substantial practical problems with its use and so fomepizole, a potent competitive inhibitor of alcohol dehydrogenase, was developed for a hopefully better treatment for metabolically-toxic alcohol poisonings. Fomepizole has few side effects and is easy to use in practice and it may obviate the need for haemodialysis in some, but not all, patients. Hence, fomepizole has largely replaced ethanol as the toxic alcohol antidote in many countries. Nevertheless, ethanol remains an important alternative because access to fomepizole can be limited, the cost may appear excessive, or the physician may prefer ethanol due to experience.

Neurological manifestation of recreational fatal and near-fatal diethylene glycol poisonings: case series and review of literature

Diethylene glycol is a common industrial solvent which is responsible for accidental and epidemic poisoning as early as the 1930s. Due to the unavailability and unaffordability of ethanol, people in Qatar among the low income group are consuming household chemicals, some of which contain diethylene glycol, for recreational purposes.The history of ingestion is usually not volunteered and the initial clinical presentation is usually nonspecific, making it difficult to diagnose from the clinical presentation. Moreover, the biochemical profile varies with time, making the diagnosis more difficult. The neurological course and toxicity is less well characterized than its renal counterpart. Moreover, reports in the literature of such recreational poisoning is lacking particularly in the region.Three cases of recreational diethylene glycol poisoning seen in Hamad General Hospital, Doha, Qatar from 2009 to 2012 are detailed here.These illustrate the clinical course with emphasis on the neurological sequelae that include encephalopathy and multiple cranial and peripheral neuropathies with fatal and near-fatal outcomes. Neuroimaging in 2 were initially normal, but follow-up imaging showed brain atrophy. The third patient's neuroimaging showed diffuse brain edema with evidence of transtentorial herniation. Nerve conduction studies were performed in 2 of the 3 cases and showed evidence of mixed sensorimotor neuropathy. The outcomes were death in 1 and severe neurological morbidity and disability in 2 cases.Diethylene glycol is a dangerous substance when ingested and can result in mortality and severe morbidity, particularly from the renal and neurological manifestations. Whereas the mechanism of damage is less well known, the damage is likely dose related. The typical clinical pattern of evolution of the poisoning in the absence of cost-effective ways to detect it in the serum can help clinicians in making the diagnosis.Neurological manifestations may include encephalopathy and multiple cranial and peripheral neuropathies with subsequent brain atrophy. Public awareness of the danger of such recreational use should be raised.