Outcomes of patients with rodenticide poisoning at a far east poison center

Changing trends in the profile of rodenticide poisoning

Background

Deliberate self-poisoning (DSP) is one of the leading causes of mortality and morbidity, with rodenticides being common compounds used by many victims. However, comprehensive data regarding the spectrum and outcome of rodenticide poisoning is scant.

Method

This retrospective study was conducted in the Emergency Department (ED) of a large tertiary care hospital in South India between January 2017 and December 2018. All patients with deliberate consumption of rodenticides were included in the analysis.

Results

During the study period, 1802 patients presented with DSP, among which 145 (8%) consumed rodenticide compounds. The mean (SD) age was 27.9 (10.7) years. Young adults (16-30 years) comprised 73% (106/145) of the study population. The majority (87%) were triaged as priority 2, while 10% were triaged as priority 1. Common rodenticide compounds consumed were yellow phosphorous (57%: 82/145), coumarins (12%: 17/145), zinc phosphide (19%: 27/145), and aluminum phosphide (1%: 1/145). A significant proportion of patients (18.6%) were under the influence of alcohol. Among the 73 males, 25 (34.2%) gave a history of co-consumption of alcohol. There was a history of previous DSP attempts in 6%. The majority (68%) of the patients were discharged alive from the hospital, and the in-hospital mortality rate was 9%. Age >30 years (adjusted OR: 2.2; 95% CI: 1.00-5.05; p value: 0.04) was an independent predictor of poor outcome.

Conclusion

Rodenticide compound consumption for DSP is prevalent in young adults and is associated with significant mortality, especially with yellow phosphorous poisoning. The current trend in our country of the increasing use of highly fatal phosphorous compounds over the innocuous coumarin derivatives is a cause of grave concern.

Reversible leukoencephalopathy caused by 2 rodenticides bromadiolone and fluoroacetamide: A case report and literature review

RATIONALE

With the easy access, rodenticide poisoning has been a public health problem in many countries. Characteristics of central nervous system (CNS) lesions induced by rodenticides are scarcely reported.

PATIENT CONCERNS

We presented a case of a 40-year-old man with seizure and consciousness disorder, coagulation dysfunction, and symmetric lesions in white matter and corpus callosum.

DIAGNOSIS

He was diagnosed with rodenticide poisoning due to bromadiolone and fluoroacetamide.

INTERVENTIONS

He was treated with vitamin K, hemoperfusion, acetamide, and calcium gluconate.

OUTCOMES

His leukoencephalopathy was reversed rapidly with the improvement of clinical symptoms.

LESSONS

This report presented the impact of rodenticide poisoning on CNS and the dynamic changes of brain lesions, and highlighted the importance of timely targeted treatments.

Superwarfarin (Long-Acting Anticoagulant Rodenticides) Poisoning: from Pathophysiology to Laboratory-Guided Clinical Management

Superwarfarins are long-acting anticoagulant rodenticides developed from warfarin. The mechanism of action is by inhibition of vitamin K epoxide reductase, resulting in the inability of the body to recycle vitamin K. Deficiency of vitamin K thereafter leads to inability for the body to synthesise vitamin K-dependent coagulation factors, factor II, VII, IX, and X, leading to prolonged prothrombin time. Due to the bulky aromatic sidechains, superwarfarins have a much longer half-life when compared to warfarin, and exposure to superwarfarins results in a prolonged period of anticoagulation which can result in clinical bleeding. Diagnosis is straightforward in patients with known history of superwarfarin exposure but has proved difficult for patients who did not report superwarfarin intake. Superwarfarin poisoning should therefore be suspected in all patients with unexplained prolongation of prothrombin time, and can be confirmed by their detection in serum. Treatment for superwarfarin poisoning includes rapid correction of factor deficiencies with either 4-factor prothrombin complex concentrate or fresh frozen plasma in patients with active bleeding, and high dose vitamin K therapy given multiple times per day for a prolonged period of weeks to months.

Distinct psychopathology of patients who attempted suicide with rodenticide in Taiwan: a comparative study with patients of suicide with paraquat

Objective

Rodenticide as a means of suicide has been documented for centuries. However, this method is often discussed in conjunction with other pesticides. Thus, we aimed to focus on patients who committed suicide with rodenticide and compared them with those who used paraquat for suicide, another frequently used yet lethal method, to highlight the different psychopathology of patients who choose rodenticide as their means of suicide.

Methods

A 12-year retrospective chart review was conducted on the medical records of all patients admitted to Chang Gung Memorial Hospital due to attempted suicide by either rodenticide or paraquat. Psychiatric consultation sheets were collected to ascertain the psychiatric comorbidity and the major stressor for suicide, measured by the Social Readjustment Rating Scale. A χ² test and logistic regression were used for group comparisons.

Results

Seventeen rodenticide and 157 paraquat suicide attempts were identified. Compared with suicides by paraquat, suicides by rodenticide had a more even distribution in the gender ratio but a lower Social Readjustment Rating Scale score (p<0.001). Depressive disorder was the most common diagnosis in suicides by rodenticide and paraquat. However, schizophrenia and psychotic disorder (29.4%) was the second most common diagnosis and a significant predictor of suicide by rodenticide (odds ratio =9.21, 95% confidence interval =1.2–66.07, p=0.027).

Conclusion

High comorbidity of psychosis in suicide by rodenticide warrants disease-specific suicide prevention and additional large-scale research to confirm this association.

Retrospective Study of the Characteristics of Anticoagulant-Type Rodenticide Poisoning in Hong Kong

INTRODUCTION

Warfarin- and superwarfarin-type anticoagulants are commonly used as rodenticides. Exposure to these agents, especially superwarfarins with long-acting anticoagulant effect, can cause life-threatening coagulopathy in humans. Most superwarfarin poisoning cases had an obvious history of exposure, though occult cases without exposure history have also been reported. The current study aims to examine anticoagulant-type rodenticide poisoning in Hong Kong and to identify the similarities and differences between patients with known exposure history and those whose exposure is recognized only through laboratory testing.

METHODS

The present study was conducted in a tertiary referral clinical toxicology laboratory in Hong Kong. This was a retrospective cohort study of all patients with biochemically confirmed anticoagulant-type rodenticide exposure, from 2010 to 2014.

RESULTS

Superwarfarin was the most common group of anticoagulant-type rodenticides identified (87.8%), in which bromadiolone and brodifacoum were the most frequently encountered. Among the 41 cases identified, 31 had an obvious exposure history, and 10 were occult poisoning in which the context of exposure remained unidentified. All occult poisoning patients without exposure history presented with bleeding events. These occult poisoning cases often went unrecognized by frontline clinicians, leading to delayed investigation and initiation of treatment. This group of patients was associated with a longer time to diagnose coagulopathy (p < 0.001) and confirm rodenticide poisoning (p < 0.05), a higher rate of international normalized ratio (INR) rebound after initiation of antidote (p < 0.001), and a longer time needed for normalizing INR (p < 0.05).

CONCLUSION

Occult superwarfarin poisoning is an important yet under-recognized differential cause of unexplained coagulopathy. A high index of clinical suspicion and availability of specialized toxicological test for superwarfarins play a vital role in diagnosis and early initiation of appropriate management. The underlying cause of such poisoning remains obscure and warrants further study.

Effects of bromadiolone poisoning on the central nervous system

Cases of rodenticide poisoning (second-generation long-acting dicoumarin rodenticide, superwarfarin) have occasionally been reported. The main symptoms of bromadiolone poisoning are skin mucosa hemorrhage, digestive tract hemorrhage, and hematuresis. However, the symptoms of central nervous system toxicity have rarely been reported. Our case reports on a 41-year-old male who had no contact with bromadiolone. His main symptoms were dizziness, unsteady gait, and abnormal behavior. Laboratory test results revealed the presence of bromadiolone in his blood and urine, a longer prothrombin time, activated partial thromboplastin time, and a high international normalized ratio. Magnetic resonance imaging of the brain showed that the bilateral posterior limb of the internal capsule, splenium of corporis callosum, and bilateral centrum semiovale formed symmetrical patch distribution. The patient gradually recovered after treated with vitamin K1 and plasma transfusion. Our clinical study could pave the way to improve the detection of bromadiolone poisoning and avoid misdiagnosis.

Long-Acting Anticoagulant Rodenticide (Superwarfarin) Poisoning: A Review of Its Historical Development, Epidemiology, and Clinical Management

Long-acting anticoagulant rodenticides (LAARs) inhibit vitamin K epoxide reductase (VKOR). Related bleeding may present a diagnostic challenge and require administration of blood component therapy, hemostatic agents, and vitamin K. This article intends to provide the reader a comprehensive understanding of LAAR poisoning. An exhaustive literature search of PubMed, Science Direct, US National Library of Medicine Toxicology Data Network, and Google Scholar yielded 174 reported cases of LAAR poisoning from which clinical data were extracted and reviewed. In addition, 25 years of epidemiologic data from the American Association of Poison Control Centers was reviewed. In the United States, on average, there were 10413 exposures reported with 2750 patients treated annually. For 25 years, there were 315951 exposures reported with nearly 90% among children and more than 100000 patients treated in a health care facility. Fortunately, only 2% of all exposures result in morbidity or mortality. Inhalational, transcutaneous, and oral routes of exposure have been documented. Most exposures are unintentional. The most frequently reported bleeding sites are mucocutaneous, with hematuria being the most common feature. Deaths were most commonly associated with intracranial hemorrhage. Long-acting anticoagulant rodenticide-induced paradoxical thrombosis and thrombotic complications accompanying hemostatic therapy have also been observed. Most patients present with coagulation assay values beyond measurable limits. Long-acting anticoagulant rodenticides have an extremely high affinity for VKOR compared with warfarin, characterized by rebound coagulopathy and bleeding after initial treatment and the need for high-dose, long-term therapy with vitamin K1. Treatment of acute hemorrhagic symptoms often required intravenous vitamin K1 in excess of 50 to 100 mg; chronic maintenance with 100 mg PO vitamin K1 daily was the most frequently used dose required to suppress coagulopathy. Treatment courses averaged 168 days. Adjunctive hemostatic therapy with recombinant factor VIIa and prothrombin complex concentrate has been reported, and phenobarbital has been used to expedite LAAR metabolism.

Brodifacoum induces early hemoglobinuria and late hematuria in rats: novel rapid biomarkers of poisoning

INTRODUCTION

Brodifacoum (BDF) is a superwarfarin that is used primarily as a rodenticide. There have been increasing numbers of reports of human cases of accidental or intentional BDF ingestion with high mortality rate. Its broad availability and high lethality suggest that BDF should be considered a potential chemical threat. Currently, there is no biomarker for early detection of BDF ingestion in humans; patients typically present with severe coagulopathy. Since we demonstrated earlier that warfarin can induce acute kidney injury with hematuria, we tested whether BDF would also lead to change in urinary biomarkers.

MATERIAL AND METHODS

BDF was administered to Sprague Dawley rats via oral gavage. N-acetylcysteine (NAC) was given per os in drinking water 24 h prior to BDF. Urinalysis was performed at different times after BDF administration. Anticoagulation and serum creatinine levels were analyzed in the blood.

RESULTS

We observed that within a few hours the animals developed BDF-dose-dependent transient hemoglobinuria, which ceased within 24 h. This was accompanied by a transient decrease in hematocrit, gross hemolysis and an increase in free hemoglobin in the serum. At later times, animals developed true hematuria with red blood cells in the urine, which was associated with BDF anticoagulation. NAC prevented early hemoglobinuria, but not late hematuria associated with BDF.

CONCLUSIONS

We propose that transient early hemoglobinuria (associated with oxidative stress) with consecutive late hematuria (associated with anticoagulation) are novel biomarkers of BDF poisoning, and they can be used in clinical setting or in mass casualty with BDF to identify poisoned patients.

Outcomes of patients with acetaminophen-associated toxic hepatitis at a far east poison center

BACKGROUND

There is an overall paucity of data regarding the outcomes of patients with acetaminophen-associated toxic hepatitis in Taiwan. Therefore, the purpose of this study was to recruit a larger number of patients and to examine the clinical features, the degrees of toxic hepatitis, the physiological markers, and the clinical outcomes after intentional acetaminophen poisoning, and to determine what association, if any, might exist between these findings.

METHODS

We examined the medical records of 187 patients with intentional acetaminophen poisoning who were examined at Chang Gung Memorial Hospital between 2000 and 2011. Patients were categorized into 2 groups according to hepatic complications, i.e. with (n = 15) or without (n = 172) toxic hepatitis. Demographic, clinical, and laboratory data were collected, and the mortality rate was analyzed.

RESULTS

It was found that patients with toxic hepatitis had higher serum acetaminophen level (P = 0.007), but they also arrived to the hospital later (P < 0.001) than patients without toxic hepatitis. Furthermore, patients with toxic hepatitis showed higher incidences of acute respiratory failure (P = 0.012) than those shown by patients who did not have hepatitis. The laboratory examinations also revealed greater degrees of granulocytosis (P < 0.001) and poorer liver function tests (P < 0.001) in patients with hepatitis than in patients without hepatitis. Nevertheless, a univariate logistic regression model failed to identify any significant risk factors for toxic hepatitis complication after ingestion (P > 0.05). At the end of the analysis, 1 patient with toxic hepatitis died of liver failure. Finally, there was no significant difference in mortality between patients with and without hepatitis (P = 0.080).

CONCLUSION

The analytical data revealed that toxic hepatitis was not uncommon (15/187 or 8.0%) after acetaminophen overdose. Further studies are warranted.