Fatality from acute chlorfenapyr poisoning

A clinical warning in the treatment of chlorfenapyr poisoning

Chlorfenapyr, an arylpyrrole-based insecticide, disrupts mitochondrial oxidative phosphorylation to deprive the target organism of energy. Chlorfenapyr poisoning in humans causes distinct clinical signs such as hyperhidrosis, malignant hyperthermia, rhabdomyolysis, and delayed neurological symptoms that worsen over time and can be fatal. When treating acute chlorfenapyr poisoning, physicians must consider the latent period and not assume that a patient is safe after an initial response to treatment. It is important to take measures before sudden, fatal symptoms appear. This paper presents three cases of chlorfenapyr poisoning as a warning for physicians to understand its clinical course and treatment.

Chlorfenapyr poisoning: a systematic review

INTRODUCTION

Chlorfenapyr, a N-substituted halogenated pyrrole, is a broad-spectrum insecticide. The insecticidal activity of chlorfenapyr depends on its biotransformation by hepatic cytochrome P450 monooxygenases to tralopyril, which uncouples mitochondrial oxidative phosphorylation and disrupts adenosine triphosphate production. Neither the metabolism of chlorfenapyr nor the mechanism of tralopyril is completely elucidated. Acute human chlorfenapyr poisoning is not well characterized, and best practice in management following acute exposure is unclear. The purpose of this review is to characterize acute human chlorfenapyr poisoning by its clinical course, laboratory investigations, and imaging findings and propose a management plan for acute human chlorfenapyr exposure.

METHODS

We systematically searched PubMed, Web of Science, Google Scholar, and EMBASE from inception to April 2024 across all languages for human chlorfenapyr and tralopyril cases, with descriptions of exposure, clinical manifestations, and clinical course included. Only manuscripts and abstracts from scientific conferences with sufficient clinical data following acute human exposures were included. In vitro studies, animal studies, agricultural studies, environmental impact studies, and non-clinical human studies were excluded. We then reviewed citations of included studies for additional eligible publications. Non-English publications were translated using Google Translate or primarily translated by our authors. The study adhered to Preferred Reporting for Systematic Reviews and Meta-analyses (PRISMA) guidelines for systematic reviews.

RESULTS

We identified 3,376 publications of which 48 met study inclusion criteria, describing 75 unique cases of human poisoning from ingestion, inhalation, dermal exposure, and intra-abdominal injection of chlorfenapyr. No cases of tralopyril exposure were identified. The median time from exposure to symptom onset was six hours (interquartile range 1-48 hours). The most frequent initial or presenting signs/symptoms included diaphoresis, nausea and/or vomiting, and altered mental status. While hyperthermia (≥38 degrees centigrade) was less common at presentation, hyperthermia developed in 61 percent of all patients and was temporally associated with clinical deterioration and death. Most common laboratory abnormalities included elevated blood creatine kinase activity, hepatic aminotransferase activities, and lactate concentration. Imaging studies of the central nervous system often showed extensive symmetrical white matter abnormalities with swelling. Case fatality was 76 percent, and survivors commonly experienced sustained neurological sequelae. Management strategies were highly varied, and the effectiveness of specific medical interventions was unclear.

DISCUSSION

Acute human chlorfenapyr poisoning is characterized by a latent period as long as 14 days, deterioration over hours to days, and can result in serious morbidity and mortality. Development of hyperthermia, likely driven by oxidative phosphorylation uncoupling by tralopyril, is an ominous clinical sign and is temporally associated with clinical decompensation and death. Laboratory abnormalities, particularly elevated creatine kinase activity, hepatic aminotransferase activities, and lactate concentration, were common, but only creatine kinase activity differed amongst survivors and fatalities. Best clinical practice in the management of patients exposed to chlorfenapyr is unclear, and we opine that a conservative approach with close clinical monitoring and supportive care is prudent.

LIMITATIONS

The limitations of all reviews include their inherent retrospective and observational nature as well as publication bias that emphasizes severe outcomes, thus impacting the spectrum of illness and skewing mortality percentage. In addition, we interrogated a finite number of databases for publications on human chlorfenapyr exposure and there were limited cases with laboratory testing to confirm chlorfenapyr poisoning. Analysis of our systematic review was not powered to detect differences between groups, comparative statistics were not performed, and significance is not reported.

CONCLUSIONS

Acute human chlorfenapyr toxicity is characterized by a latent period following exposure, development of new or progression of established signs/symptoms, potential for critical illness, rapid deterioration, serious morbidity, and mortality. A conservative approach to patient management is prudent.

Delayed death of a child from chlorfenapyr poisoning: A case report and literature review

This was the first article reported a fatal case of chlorfenapyr poisoning in a child, and the typical symptoms before death include high fever, severe sweating, coma, and limb stiffness, and elevation of myocardial enzymes and myoglobin; neurological symptoms tend to appear earlier in children than in adults.

Chlorfenapyr poisoning: mechanisms, clinical presentations, and treatment strategies

BACKGROUND

Chlorfenapyr is used to kill insects that are resistant to organophosphorus insecticides. Chlorfenapyr poisoning has a high mortality rate and is difficult to treat. This article aims to review the mechanisms, clinical presentations, and treatment strategies for chlorfenapyr poisoning.

DATA RESOURCES

We conducted a review of the literature using PubMed, Web of Science, and SpringerLink from their beginnings to the end of October 2023. The inclusion criteria were systematic reviews, clinical guidelines, retrospective studies, and case reports on chlorfenapyr poisoning that focused on its mechanisms, clinical presentations, and treatment strategies. The references in the included studies were also examined to identify additional sources.

RESULTS

We included 57 studies in this review. Chlorfenapyr can be degraded into tralopyril, which is more toxic and reduces energy production by inhibiting the conversion of adenosine diphosphate to adenosine triphosphate. High fever and altered mental status are characteristic clinical presentations of chlorfenapyr poisoning. Once it occurs, respiratory failure occurs immediately, ultimately leading to cardiac arrest and death. Chlorfenapyr poisoning is difficult to treat, and there is no specific antidote.

CONCLUSION

Chlorfenapyr is a new pyrrole pesticide. Although it has been identified as a moderately toxic pesticide by the World Health Organization (WHO), the mortality rate of poisoned patients is extremely high. There is no specific antidote for chlorfenapyr poisoning. Therefore, based on the literature review, future efforts to explore rapid and effective detoxification methods, reconstitute intracellular oxidative phosphorylation couplings, identify early biomarkers of chlorfenapyr poisoning, and block the conversion of chlorfenapyr to tralopyril may be helpful for emergency physicians in the diagnosis and treatment of this disease.

A Comprehensive Review of the Current Knowledge of Chlorfenapyr: Synthesis, Mode of Action, Resistance, and Environmental Toxicology

Creating new insecticide lead compounds based on the design and modification of natural products is a novel process, of which chlorfenapyr is a typical successful example. Chlorfenapyr is an arylpyrrole derivative that has high biological activity, a wide insecticidal spectrum, and a unique mode of action. For decades, a series of chlorfenapyr derivatives were designed and synthesized continuously, of which many highly active insecticidal compounds were discovered sequentially. However, due to the widespread application of chlorfenapyr and its degradation properties, some adverse effects, including pest resistance and environmental toxicity, occurred. In this review, a brief history of the discovery and development of chlorfenapyr is first introduced. Then, the synthesis, structural modification, structure activity relationship, and action mechanism of arylpyrroles are summarized. However, challenges and limitations still exist, especially in regard to the connection with pest resistance and environmental toxicology, which is discussed at the end of this review. This comprehensive summary of chlorfenapyr further promotes its progress and sensible application for pest management.

A Fatal Case of Chlorfenapyr Poisoning and the Therapeutic Implications of Serum Chlorfenapyr and Tralopyril Levels

Chlorfenapyr is a new contact and stomach insecticide derived from natural pyrroles secreted by Streptomyces spp. It is a pro-insecticide and acts after metabolic transformation to its active metabolite tralopyril. Tralopyril is an uncoupler of oxidative phosphorylation in the mitochondria of the target insects and of experiment animals, leading to the disruption of adenosine triphosphate synthesis and death. Several fatal human poisonings had been reported and no blood chlorfenapyr or tralopyril measurements were available. The treatment remains supportive. A 32-year-old healthy man ingested 200 mL of 10% chlorfenapyr as a suicide attempt. Unfortunately, he succumbed at 157 h post-ingestion, shortly after having fever and seizures. His serum level of chlorfenapyr at 4 h post-exposure was 77.4 ng/mL, and was undetectable at 113 and 156 h, respectively. The serum levels of tralopyril were 723.6, 14,179, and 9654.2 ng/mL at 4, 113, and 156 h post-ingestion, respectively. The delay in the rise of serum tralopyril levels was noticeable, which seems to correlate with the patient’s signs and symptoms. The information may have therapeutic implications in the management of this deadly poisoning.

A fatal case of chlorfenapyr poisoning and a review of the literature

BACKGROUND

Chlorfenapyr is a widely used pesticide and is classified as moderately hazardous to human health. Ingestion usually leads to mortality in humans. However, chlorfenapyr toxicity has a variable course and mechanism of action.Case presentation: We report the case of a 79-year-old female who ingested chlorfenapyr with the intent to commit suicide. The liquid was ingested 2 hours before she was brought to our emergency department. Gastric lavage was immediately performed. On admission, laboratory examinations revealed mildly elevated liver enzyme and creatinine kinase levels. Acute fever occurred on day 7; on day 8, the patient died of progressive respiratory distress and conscious disturbance. Chlorfenapyr toxicity leads to high rates of mortality (75%) and causes damage to the liver and the nervous system.

CONCLUSIONS

It is necessary to observe patients with chlorfenapyr toxicity for 3 weeks because no significant abnormalities occur in the early phase. The onset of fever and deterioration of consciousness is a warning sign of a sudden fatal outcome. We review the literature and discuss neurologic and cardiopulmonary impairment in the clinical course of chlorfenapyr poisoning.

Malignant hyperthermia-like syndrome in acute chlorfenapyr poisoning- a case report

Background

Chlorfenapyr is a pesticide that interferes with mitochondrial oxidative phosphorylation, resulting in the disruption of ATP production and cellular death. We present a fatal case of chlorfenapyr poisoning presented with malignant hyperthermia- like syndrome after intubation.

Case presentation

A 49-year-old male presented with fatigue and diaphoresis four days after ingesting emamectin chlorfenapyr. IV hydration was given, and two sessions of hemoperfusion were performed. He was intubated for airway protection on Day 3 because of drowsiness. Immediately after intubation, he developed tachycardia and hyperthermia (temperature 41 °C), followed by cardiac arrest. During resuscitation, we noted he had severe diaphoresis and generalized muscle rigidity. Peri-arrest ABG showed abrupt onset of severe type 2 respiratory failure, lactate acidosis, and hyperkalemia. The clinical manifestation and ABG result lead to the possible diagnosis of malignant hyperthermia. The resuscitation was unsuccessful, and the patient eventually passed away. Propofol might be the culprit drug in this case as it is known to affect mitochondrial metabolism via uncoupling oxidative phosphorylation.

Conclusion

We suggest monitoring for signs and symptoms of malignant hyperthermia in chlorfenapyr poisoning, especially after intubation. Propofol should be avoided or used with caution during induction for intubation. Further research on the possible antidote and usage of early RRT in ED is needed.

Acute chlorfenapyr toxicity in 3 dogs from a single household

OBJECTIVE

To describe the clinical characteristics of acute chlorfenapyr toxicity in 3 dogs from a single household.

CASE SUMMARY

A 4-year-old neutered female Labrador Retriever was presented with severe hyperthermia (42.6°C [108.6°F]). Emergency management consisting of fluid resuscitation, active cooling, general anesthesia, gastric lavage, activated charcoal administration, and intravenous lipid emulsion was started immediately on the suspicion of toxin exposure. The dog developed symptoms following peracute death in 2 other small breed dog housemates. All dogs had a rapid onset of gastrointestinal signs, neurologic signs, and panting. The dog made a rapid and complete recovery and was discharged 48 hours later. Examination of gastric contents collected from the deceased dogs identified the presence of chlorfenapyr.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first reported case of chlorfenapyr toxicity in dogs. Previous case reports in human medicine have reported a variable mortality rate, although 1 of 3 dogs described here made a complete recovery. Chlorfenapyr should be considered in cases of suspected toxicity with similar presenting signs.

Delayed hyperthermia from chlorfenapyr overdose

We describe the hospital course of a 42-year-old patient who presented to the Emergency Department following an ingestion of an unknown quantity of chlorfenapyr, an organochlorine pesticide that acts as a mitochondrial uncoupler (MU). There is limited data on chlorfenapyr toxicity in humans, but reports indicate a 100% mortality rate after a 7-10 day quiescent period.3-6 Our patient was admitted for a 5-day asymptomatic observation period before becoming critically ill. Supportive care, antioxidant therapy, and late hemodialysis (HD) proved futile. The patient expired from complications due to uncontrollable hyperthermia on hospital day 6. This case represents the first reported fatality due to chlorfenapyr in North America, and illustrates: 1) its potency as a human toxin, 2) the futility of extracorporeal decontamination once late toxicity has set in; 3) the potential need for early and aggressive decontamination in the ED; and 4) the need for a better understanding of this unique poison.

A fatal case of chlorfenapyr poisoning following dermal exposure

Introduction:

Chlorfenapyr is a pyrrole-based pro-insecticide. The main activity of this agent is the inhibition of adenosine triphosphate synthesis, and it is used in agriculture to control several insects and mites resistant to carbamate, organophosphate and pyrethroid insecticide. The World Health Organization classifies this agent as a class II toxin (moderately hazardous).

Case presentation:

All previously reported cases of chlorfenapyr poisoning in humans occurred following oral ingestion except one case involving exposure to chlorfenapyr vapour.

Discussion:

In this report, we describe a case of chlorfenapyr intoxication after skin exposure in a 49-year-old patient who died 5 days after exposure. Conclusion: This case demonstrates that similar to oral ingestion, dermal absorption of chlorfenapyr may also be fatal.

Chlorfenapyr-Induced Toxic Leukoencephalopathy with Radiologic Reversibility: A Case Report and Literature Review

Chlorfenapyr is a widely used, moderately hazardous pesticide. Previous reports have indicated that chlorfenapyr intoxication can be fatal in humans. We reported the first non-fatal case of chlorfenapyr-induced toxic leukoencephalopathy in a 44-year-old female with resolution of extensive and abnormal signal intensities in white matter tracts throughout the brain, brain stem, and spinal cord on serial magnetic resonance imaging.

The initial hyperglycemia in acute type II pyrethroid poisoning

This retrospective observational case series study was conducted to describe the clinical feature of acute type II pyrethroid poisoning, and to investigate whether hyperglycemia at presentation can predict the outcome in patients with type II pyrethroid poisoning. This study included 104 type II pyrethroid poisoned patients. The complication rate and mortality rate was 26.9% and 2.9% in type II pyrethroid poisoned patients. The most common complication was respiratory failure followed by acidosis and hypotension. In non-diabetic type II pyrethroid poisoned patients, patients with complications showed a higher frequency of hyperglycemia, abnormalities on the initial X ray, depressed mentality, lower PaCO2 and HCO3- levels, and a higher WBC and AST levels at the time of admission compared to patients without complication. Hyperglycemia was an independent factor for predicting complications in non-diabetic patients. Diabetic patients had a significantly higher incidence of complications than non-diabetic patients. However, there was no significant predictive factor for complications in patients with diabetes mellitus probably because of small number of diabetes mellitus. In contrast to the relatively low toxicity of pyrethroids in mammals, type II pyrethroid poisoning is not a mild disease. Hyperglycemia at presentation may be useful to predict the critical complications in non-diabetic patients.

A case of survival after chlorfenapyr intoxication with acute pancreatitis

Chlorfenapyr is a moderately hazardous insecticide. There have been previous reports of chlorfenapyr intoxication, but none have reported patient survival or an association with pancreatitis. A 61-year-old woman was brought to the emergency department with vomiting after ingesting 10 mL chlorfenapyr in a suicide attempt 1 hour before. The patient was treated with gastric lavage and activated charcoal, then transferred to the intensive care unit. Initial laboratory data were unremarkable except for elevated amylase/lipase levels (134/222 U/L), which were even higher 7 days later and remained elevated for 2 weeks. Abdominal computed tomography showed diffuse pancreatic swelling. The patient improved with conservative care and was discharged to home 19 days after admission. This is the first reported case of survival after chlorfenapyr intoxication. We recommend early aggressive management in the emergency department and close monitoring in the intensive care unit to detect and treat potentially fatal deterioration after chlorfenapyr intoxication.

A patient fatality following the ingestion of a small amount of chlorfenapyr

Chlorfenapyr has been used worldwide for agricultural pest control since 1995. Despite its widespread use, acute human poisoning data are insufficient; only a small number of fatalities from chlorfenapyr poisoning have been reported. The signs and symptoms of chlorfenapyr toxicity include nausea, vomiting, fever, rhabdomyolysis, among others. In addition, central nervous system effects in association with delayed toxicity have also been observed. Here, we detail a fatality resulting from delayed chlorfenapyr toxicity following the ingestion of a small amount of pesticide.

Toxicity from intra-abdominal injection of chlorfenapyr

Introduction. Chlorfenapyr is commonly used for food crops in Korea. However, chlorfenapyr toxicity in humans has not yet been studied. Case. A 74-year-old man was admitted to the emergency room after he intra-abdominally injected 20 mL of chlorfenapyr in an attempt to commit suicide. Emergency surgery was performed and accumulation of approximately 500 mL of reactive fluid in the abdomen was observed. The entire small intestine showed congestion. After surgery, additional surgery to drain the fluid was performed on POD 12. But immediately after administration of general anesthesia, flat rhythm was observed by electrocardiogram (ECG) monitoring, requiring cardiopulmonary resuscitation (CPR). Discussion. The color of the bowel was purple, indicating ischemic injury. This could be attributed to direct absorption of the substance through the peritoneum, leading to chemical injury to the small intestine serosa, unlike in the case of oral ingestion. This resulted in an ischemic change in the small intestine, eventually leading to sepsis. Conclusion. Only a few cases of chlorfenapyr toxicity have been reported in the literature, and death occurred in all cases, including our case. Therefore, careful and aggressive treatments are necessary. This is the first reported case of intra-abdominal injection of chlorfenapyr.