Superwarfarin poisoning: a report of two cases and review of the literature

Amyloidogenic and Neuroinflammatory Molecular Pathways Are Contrasted Using Menaquinone 4 (MK4) and Reduced Menaquinone 7 (MK7R) in Association with Increased DNA Methylation in SK-N-BE Neuroblastoma Cell Line

Besides its role in coagulation, vitamin K seems to be involved in various other mechanisms, including inflammation and age-related diseases, also at the level of gene expression. This work examined the roles of two vitamin K2 (menaquinones) vitamers, namely, menaquinone-4 (MK4) and reduced menaquinone-7 (MK7R), as gene modulator compounds, as well as their potential role in the epigenetic regulation of genes involved in amyloidogenesis and neuroinflammation. The SK-N-BE human neuroblastoma cells provided a "first-line" model for screening the neuroinflammatory and neurodegenerative molecular pathways. MK7R, being a new vitamin K form, was first tested in terms of solubilization, uptake and cell viability, together with MK4 as an endogenous control. We assessed the expression of key factors in amyloidogenesis and neuroinflammation, observing that the MK7R treatment was associated with the downregulation of neurodegeneration- (PSEN1 and BACE1) and neuroinflammation- (IL-1β and IL-6) associated genes, whereas genes retaining protective roles toward amiloidogenesis were upregulated (ADAM10 and ADAM17). By profiling the DNA methylation patterns of genes known to be epigenetically regulated, we observed a correlation between hypermethylation and the downregulation of PSEN1, IL-1β and IL-6. These results suggest a possible role of MK7R in the treatment of cognitive impairment, giving a possible base for further preclinical experiments in animal models of neurodegenerative disease.

Tyrant’s End: Did Joseph Stalin Die From Warfarin Poisoning?

One of the most brutal dictators in humanity's history, Joseph Stalin forged the Soviet Union into a massive superpower, crushing the lives of millions of his own citizens along the way. His sudden death in March 1953 from a stroke took the world by surprise and led to a frantic power struggle within the ranks of the Soviet government. In recent years, researchers have proposed that Stalin's stroke was not natural and was potentially caused by one of his lieutenants poisoning him with warfarin or a similar anticoagulant. After examining the evidence, this article concludes that both Stalin's disease course and the properties of warfarin make it highly unlikely that he was deliberately assassinated.

Establishment and Validation of Anticoagulant Rodenticides in Animal Samples by HPLC-MS/MS, Focusing on Evaluating the Effect of Modified QuEChERS Protocol on Matrix Effect Reduction

A rapid, accurate, and selective analytical method to simultaneously quantify 13 anticoagulant rodenticides in animal biological samples was developed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) coupled with electrospray ionization (ESI) in negative mode. Samples were extracted and purified based on a modified QuEChERS (quick, easy, cheap, effective, rugged, safe) sample preparation technique. The sample pH and the type of extraction solvent and cleanup sorbent used to estimate the procedure's effectiveness were optimized. To improve the matrix effects and obtain acceptable recoveries for 13 rodenticides, 0.1 mL/g biological sample and 1 mL acetonitrile (or acetonitrile: EtOAc = 1:1/(v:v)) extraction followed by Florisil/HC-C18/anhydrous Na₂SO₄ (NaCl) cleanup under alkaline conditions was fully validated and shown to be selective, precise, accurate, and linear in the range from 1 to 100 ng/mL (g). The mean recoveries were between 52.78 and 110.69%, while the limits of detection and quantification ranged from 0.05 to 0.5 and 0.1-1 ng/mL (μg/kg), respectively. Ideal soft matrix effects (≤20%) were observed for the vast majority of rodenticides (>95%) showing either suppression or enhancement. This method meets international criteria and is capable of simultaneously identifying and quantifying anticoagulant rodenticides in animal blood and tissues and can be suitable for the detection of poisoning cases in the field of forensic or public health.

The Public Health Response to a Large Poisoning Outbreak Involving an Illicit Substance: Synthetic Cannabinoids Contaminated With a Long-Acting Anticoagulant Rodenticide, Illinois, March-July, 2018

During March-July 2018, the Illinois Department of Public Health responded to an acute outbreak of severe coagulopathy among patients with recent synthetic cannabinoid use. Toxicological testing indicated that cases were exposed to brodifacoum, a long-acting anticoagulant rodenticide. A total of 174 confirmed and probable cases, including 5 deaths, were linked to this outbreak. On the basis of the experience of responding to this complex outbreak, we recommend several steps for consideration to improve health department preparation for acute outbreaks involving illicit substances including strengthening communication between public health and law enforcement agencies, reviewing legal authority to investigate noninfectious acute disease outbreaks, continuing strong partnerships with state poison control centers, partnering with substance abuse and mental health agencies to provide services to patients, and determining health department ability to rapidly enter into public-private partnership agreements.

Lethal coagulopathy resulting from the consumption of contaminated synthetic cannabinoids: the story of a public health crisis

In March 2018, Illinois saw the outbreak of an unprecedented public health crisis, which manifested as the development of a potentially lethal coagulopathy associated with the consumption of synthetic cannabinoids. This outbreak impacted a reported 174 patients, and was responsible for the deaths of five patients. While events unfolded, it was uncovered that the coagulopathy was not caused directly by the consumption of synthetic cannabinoids, but by the contamination of these products with Brodifacuom, bromadiol and difenacoum, potent Vitamin K antagonists that are the active ingredient in most rodenticides. This article chronicles the first reported instance of clinically significant Long Acting Anticoagulant Rodenticide poisoning on such a widespread and uniform scale, and examines the challenges posed to the providers and Public Health authorities tasked with the management of this outbreak. Crisis preparedness determines mitigation, response and recovery during trying times. It is prudent that healthcare agencies engage in collective measures to establish preparedness plans and build up their capacity to respond to health-related crises such as the one faced by Illinois in early 2018. By examining the solutions developed to tackle each unique challenge, the objective of this article is to lay a framework for action and response to similar public health crises.

Unintentional ingestion of a high dose of acenocoumarol in a young child

Acute intoxication with a vitamin K antagonist may cause serious coagulopathy. We report the accidental ingestion of a high dose of acenocoumarol in a young child. Two intravenous administrations of 5 mg of vitamin K, in combination with fast and repeated administration of activated charcoal and sodium sulfate, were sufficient to prevent coagulopathy and related symptoms, despite a confirmed elevated blood acenocoumarol concentration (260 µg/L).

Brodifacoum-Laced Synthetic Marijuana Toxicity: A Fight Against Time

Patient: Male, 30-year-old

Final Diagnosis: Brodifacoum toxicity

Symptoms: Abdominal pain

Medication:—

Clinical Procedure: —

Specialty: Hematology • Toxicology

Separation and Quantification of Superwarfarin Rodenticide Diastereomers-Bromadiolone, Difenacoum, Flocoumafen, Brodifacoum, and Difethialone-in Human Plasma

BACKGROUND

Superwarfarins, second-generation long-acting anticoagulant rodenticides, are 4-hydroxycoumarin analogues of warfarin that contain a large hydrophobic side chain. These compounds contain two chiral centers and are synthesized for commercial use as two pairs of diastereomer.

OBJECTIVE

To support studies of superwarfarin pharmacokinetics and other efforts to improve clinical care for poisoning victims, a quantitative assay was developed for the measurement of diastereomer of bromadiolone, difenacoum, flocoumafen, brodifacoum, and difethialone in human plasma.

METHOD

Based on ultrahigh-pressure liquid chromatography-tandem mass-spectrometry (UHPLC-MS/MS), this method was validated according to U.S. Food and Drug Administration (FDA) guidelines. Sample preparation involved simple protein precipitation followed by reversed phase UHPLC, which resolved all five pairs of cis/trans diastereomer in less than 10 min. Superwarfarins were measured using negative ion electrospray followed by selected-reaction monitoring on a triple quadrupole mass spectrometer.

RESULTS

Calibration curves covered 3-4 orders of magnitude with linear regression coefficients of >0.999. The lower limits of quantitation were from 0.013 to 2.41 ng/mL, and intra-day and inter-day accuracy and precision coefficients of variation were <12%.

CONCLUSIONS

A 10-min UHPLC-MS/MS assay was developed and validated for the separation and quantitative analysis of the pairs of diastereomer of five superwarfarins in human plasma.

HIGHLIGHTS

This method was used to identify and measure superwarfarins and their cis/trans diastereomers in plasma obtained from patients treated for coagulopathy following consumption of contaminated synthetic cannabinoid products.

Vitamin K as a Diet Supplement with Impact in Human Health: Current Evidence in Age-Related Diseases

Vitamin K health benefits have been recently widely shown to extend beyond blood homeostasis and implicated in chronic low-grade inflammatory diseases such as cardiovascular disease, osteoarthritis, dementia, cognitive impairment, mobility disability, and frailty. Novel and more efficient nutritional and therapeutic options are urgently needed to lower the burden and the associated health care costs of these age-related diseases. Naturally occurring vitamin K comprise the phylloquinone (vitamin K1), and a series of menaquinones broadly designated as vitamin K2 that differ in source, absorption rates, tissue distribution, bioavailability, and target activity. Although vitamin K1 and K2 sources are mainly dietary, consumer preference for diet supplements is growing, especially when derived from marine resources. The aim of this review is to update the reader regarding the specific contribution and effect of each K1 and K2 vitamers in human health, identify potential methods for its sustainable and cost-efficient production, and novel natural sources of vitamin K and formulations to improve absorption and bioavailability. This new information will contribute to foster the use of vitamin K as a health-promoting supplement, which meets the increasing consumer demand. Simultaneously, relevant information on the clinical context and direct health consequences of vitamin K deficiency focusing in aging and age-related diseases will be discussed.

Superwarfarin Exposure: An Important Uncommon Cause of Painless Bleeding

Painless bleeding in a patient presenting from the community with elevated coagulation studies rarely makes the physicians suspect superwarfarin or rodenticide poisoning. Although a significant number of superwarfarin exposure cases are diagnosed every year, we believe there appears to be delay in diagnosis and confusion in determining what is the ideal way to treat and monitor these patients during the management. This is the first thorough literature review of all the reported cases of superwarfarin poisoning which also studied the clinical presentation, management and follow-up patterns. We present a 70-year-old man who presented to the emergency room with epistaxis, melena, cola-colored urine with elevated prothrombin time (PT), activated partial thromboplastin time (aPTT) and international normalized ratio (INR). Mixing studies showed complete correction of coagulopathy indicative of factor deficiency. Additional history revealed that the patient had arguments with family member at home and made us suspect superwarfarin exposure. Qualitative brodifacoum testing was positive and was managed with fresh frozen plasma and high doses of vitamin K1 (phytomenadione) with serial monitoring of INR and clinical symptoms. Superwarfarin poisoning should be considered in the differential diagnosis of a patient who presents with above clinical and laboratory profile especially in the absence of any history of coagulopathy or anticoagulant use. We want to raise public and especially physician awareness that history taking, early diagnosis and managing in right clinical setting play a significant role in survival of these patients.

Unusual presentation of haemoptysis following accidental inhalation of the 'superwarfarin' rodenticide brodifacoum

Haemoptysis is a worrying symptom for patients and can represent a diagnostic challenge for clinicians. We present the case of a 56-year-old woman who presented to the emergency department with acute haemoptysis and associated sudden-onset dyspnoea. The patient remained haemodynamically stable and there was no demonstrable drop in haemoglobin concentration. Following rigorous investigations, on further questioning, the patient recalled inadvertent inhalation of the rodenticide brodifacoum. This exposure was deemed to represent the cause of their acute haemoptysis, which subsequently fully resolved without intervention.

Brodifacoum does not modulate human cannabinoid receptor-mediated hyperpolarization of AtT20 cells or inhibition of adenylyl cyclase in HEK 293 cells

Background

Synthetic cannabinoids are a commonly used class of recreational drugs that can have significant adverse effects. There have been sporadic reports of co-consumption of illicit drugs with rodenticides such as warfarin and brodifacoum (BFC) over the past 20 years but recently, hundreds of people have been reported to have been poisoned with a mixture of synthetic cannabinoids and BFC. We have sought to establish whether BFC directly affects cannabinoid receptors, or their activation by the synthetic cannabinoid CP55940 or the phytocannabinoid Δ⁹-tetrahydrocannabinol (Δ⁹-THC).

Methods

The effects of BFC on the hyperpolarization of wild type AtT20 cells, or AtT20 cells stably expressing human CB₁- or CB₂- receptors, were studied using a fluorescent assay of membrane potential. The effect of BFC on CB₁- and CB₂-mediated inhibition of forskolin-stimulated adenylyl cyclase (AC) activation was measured using a BRET assay of cAMP levels in HEK 293 cells stably expressing human CB₁ or CB₂.

Results

BFC did not activate CB₁ or CB₂ receptors, or affect the hyperpolarization of wild type AtT20 cells produced by somatostatin. BFC (1 µM) did not affect the hyperpolarization of AtT20-CB₁ or AtT20-CB₂ cells produced by CP55940 or Δ⁹-THC. BFC (1 µM) did not affect the inhibition of forskolin-stimulated AC activity by CP55940 in HEK 293 cells expressing CB₁ or CB₂. BFC (1 µM) also failed to affect the desensitization of CB₁ and CB₂ signaling produced by prolonged (30 min) application of CP55940 or Δ⁹-THC to AtT20 cells.

Discussion

BFC is not a cannabinoid receptor agonist, and appeared not to affect cannabinoid receptor activation. Our data suggests there is no pharmacodynamic rationale for mixing BFC with synthetic cannabinoids; however, it does not speak to whether BFC may affect synthetic cannabinoid metabolism or biodistribution. The reasons underlying the mixing of BFC with synthetic cannabinoids are unknown, and it remains to be established whether the “contamination” was deliberate or accidental. However, the consequences for people who ingested the mixture were often serious, and sometimes fatal, but this seems unlikely to be due to BFC action at cannabinoid receptors.

Synthetic cannabinoid-associated coagulopathy secondary to long-acting anticoagulant rodenticides: Observational case series and management recommendations

Synthetic cannabinoids have become increasingly popular drugs of abuse due to low cost and inability to detect these substances on routine drug screenings. In the United States, incidence of synthetic cannabinoid contamination with long-acting anticoagulant rodenticides (LAARs) resulting in coagulopathy and bleeding complications has been described.We sought to describe the natural history, management approach, and outcomes of bleeding secondary to synthetic cannabinoid-associated LAAR toxicity in an observational case series of patients evaluated at an urban academic medical system.We conducted an observational study of patients with suspected exposure to LAAR-contaminated synthetic cannabinoids and associated bleeding treated within the Johns Hopkins Health System.In this 16 subject cohort, hematuria was the most common bleeding symptom at presentation. The majority of the cohort (75%) had international normalized ratio (INR) > 9.6 at presentation. Of the 13 patients with brodifacoum testing, 12/13 (92%) were positive. Twelve patients (75%) had at least 1 INR value below 2 within 24 hours of the first INR measurement. Of this cohort, 1/16 (6%) died in hospital. The median length of hospital stay was 4 days, (interquartile range = 3-6). The average cost of pharmacological treatment for coagulopathy during inpatient hospitalization was $5300 (range, $2241-$8086).In patients presenting with unexplained coagulopathy it is important for emergency department providers to consider LAAR intoxication and consider formal testing for brodifacoum to assist with treatment planning. Use of a standardized management algorithm including intravenous/oral vitamin K, judicious use of blood products and close laboratory monitoring is essential to optimizing outcomes.

Detection of Brodifacoum and other Rodenticides in Drug Mixtures using Thermal Desorption Direct Analysis in Real Time Mass Spectrometry (TD-DART-MS)

In recent months, there has been increased reporting of seized drug and toxicology cases containing rodenticides, the active ingredient in rat poisons. Seeing as rodenticides are not scheduled substances, they are not commonly screened for in seized drug analysis. This work investigates the use of TD-DART-MS for the simultaneous detection of rodenticides and drugs. Six rodenticides were evaluated, an optimal method was established, and limits of detection in the tens of nanograms were calculated. Additional studies highlight that detection at less than 1% by weight in mixtures with AB-FUBINACA, cocaine, heroin, or methamphetamine was possible. This work presents an optimized method for detection of these compounds, allowing for the simultaneous detection of drugs and rodenticides, providing drug chemists with a tool for rapid identification of these compounds for forensic or public health purposes.

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.

An Outbreak of Synthetic Cannabinoid-Associated Coagulopathy in Illinois

BACKGROUND

In March and April 2018, more than 150 patients presented to hospitals in Illinois with coagulopathy and bleeding diathesis. Area physicians and public health organizations identified an association between coagulopathy and synthetic cannabinoid use. Preliminary tests of patient serum samples and drug samples revealed that brodifacoum, an anticoagulant, was the likely adulterant.

METHODS

We reviewed physician-reported data from patients admitted to Saint Francis Medical Center in Peoria, Illinois, between March 28 and April 21, 2018, and included in a case series adult patients who met the criteria used to diagnose synthetic cannabinoid-associated coagulopathy. A confirmatory anticoagulant poisoning panel was ordered at the discretion of the treating physician.

RESULTS

A total of 34 patients were identified as having synthetic cannabinoid-associated coagulopathy during 45 hospitalizations. Confirmatory anticoagulant testing was performed in 15 of the 34 patients, and superwarfarin poisoning was confirmed in the 15 patients tested. Anticoagulant tests were positive for brodifacoum in 15 patients (100%), difenacoum in 5 (33%), bromadiolone in 2 (13%), and warfarin in 1 (7%). Common symptoms at presentation included gross hematuria in 19 patients (56%) and abdominal pain in 16 (47%). Computed tomography was performed to evaluate abdominal pain and revealed renal abnormalities in 12 patients. Vitamin K₁ (phytonadione) was administered orally in all 34 patients and was also administered intravenously in 23 (68%). Red-cell transfusion was performed in 5 patients (15%), and fresh-frozen plasma infusion in 19 (56%). Four-factor prothrombin complex concentrate was used in 1 patient. One patient died from complications of spontaneous intracranial hemorrhage.

CONCLUSIONS

Our data indicate that superwarfarin adulterants of synthetic cannabinoids can lead to clinically significant coagulopathy. In our series, in most of the cases in which the patient presented with bleeding diathesis, symptoms were controlled with the use of vitamin K₁ replacement therapy. The specific synthetic cannabinoid compounds are not known.

Treatment for long acting anticoagulant rodenticide poisoning - beyond INR monitoring?

Poisoning by long acting anti-coagulant rodenticides (LAARs) requires long-term treatment with oral vitamin K1 (VK1). However, discontinuing treatment based on normalization of INR, may leave some patients with serum LAAR concentrations above a level considered safe. To address this, we carried out a retrospective analysis of 21 case reports of LAAR poisoning having at least two serum LAAR concentrations quantified during treatment with oral VK1. We identified the case reports by survey of existing peer-reviewed literature in which a patient presented to emergency department exhibiting bleeding or elevated INRs, and had quantitative measurements of serum LAAR concentrations. Of 21 case reports, measurement of serum LAAR concentrations following VK1 treatment showed that over half (n=11) had serum LAAR concentrations that were above a concentration considered to be safe (10 ng/mL), despite having received higher daily and total VK1 dosing, over an equivalent treatment duration. Since residual amounts of serum and tissue LAAR could contribute to symptom recurrence and repeated hospitalization, these results indicate that normalization of INR is not a sufficient criterion to discontinue VK1 treatment and that measurements of serum LAAR concentrations should be included to help guide decisions to continue or discontinue VK treatment.

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.

A 67-Year-Old Man with Epistaxis, Melena, Gross Haematuria and Haemarthrosis

Superwarfarins are widely used as rodenticides. They are similar to warfarin, but they are more potent and act longer. In case of poisoning, they cause severe bleeding, usually from multiple sites. Prolonged treatment with high doses of vitamin K and/or fresh frozen plasma (FFP) transfusions may be necessary. Awareness of the problem of superwarfarin intoxication among physicians remains low and cases may go undiagnosed for days or weeks, resulting in increased morbidity and even mortality. We presented a case of delayed diagnosis of superwarfarin ingestion. The patient presented to emergency department with epistaxis, melena, and gross haematuria. He was treated with vitamin K and the International Normalised Ratio (INR) dropped from >7.0 to 1.4. The patient was discharged. However, 3 weeks later, the patient presented with haemarthrosis. Blood investigation revealed INR value >7.0 again. The patient finally received treatment with FFP and vitamin K. This case illustrates the importance to consider superwarfarin ingestion when patients presented with poisoning with coagulopathy. (Hong Kong j.emerg.med. 2015;22:324-327)

The Epidemiology of Household Rodenticides Poisoning in Hong Kong and its Risk Factors for Developing Coagulopathy

Objective

To (1) describe the epidemiology of household rodenticides poisoning in Hong Kong, (2) evaluate the proportion of patients who have develop coagulopathy after rodenticide poisoning, (3) identify the risk factors for developing coagulopathy in rodenticide poisoning.

Design

Case series study.

Setting

Sixteen accident and emergency departments in Hong Kong.

Patients

Patients with household rodenticide ingestion who presented to accident and emergency departments during the period from July 2008 to February 2012.

Results

110 patients were reported to have rodenticide exposure during the study period. Eighty-seven patients were included in the final analysis. The mean age was 40.1 and the male-to-female ratio was 1.29:1 (49:38). Most patients (91%) took the rodenticide intentionally. Sixty-nine patients (79%) exposed to anticoagulants type of rodenticide based on history or laboratory findings. The ingredient of the rodenticide ingested in 18 patients (21%) was untraceable. The only clinically significant presentation reported after rodenticide exposure was coagulopathy. Thirty-one patients (36%) developed coagulopathy with an international normalised ratio greater or equal to 1.3. Clinical significant bleeding was only observed in one patient. Presence of coagulopathy in rodenticide poisoning was significantly associated with older patient, intentional ingestion, ingestion of warfarin, ingestion of more than one pack and presence of co-ingestion. Multiple logistic regression analysis showed that only two factors were independent predictor of coagulopathy: Ingestion of warfarin rodenticide (p=0.001, odds ratio [OR] = 18.20, 95% confidence interval [CI]=3.44-96.42), and ingestion of more than one pack of rodenticide (p=0.02, OR=10.01, 95% CI=1.43-69.87).

Conclusions

Clinically significant household rodenticide poisoning in Hong Kong is solely related to ingestion of anticoagulant type of rodenticide. Patients who have ingested warfarin rodenticide and higher ingestion dose are more likely in developing coagulopathy. (Hong Kong j.emerg.med. 2014;21:339-345)

A guide to acquired vitamin K coagulophathy diagnosis and treatment: the Russian perspective

Abstract

Physicians often come across with cases of vitamin K antagonists–dependent coagulopathy for reasons such as accidental use of the vitamin K antagonists (VKA), excessive administration of prescribed anticoagulants of indirect action or not reported administration of vitamin K antagonists due to memory impairment and/or other mental disorders, even deliberate use thereof (attempt to murder or suicide). Rodenticide-poisoning (coumarins, warfarins) via food or occupational accidents are difficult to diagnose. This article discusses different types of acquired vitamin K-dependent coagulopathy. Differential diagnosis is primarily based on patient statements before additional causes of vitamin K deficiency are explored. Even when pathological vitamin K deficiency is not determined, appropriate and urgent medical treatment is necessary: administration of fresh frozen plasma or concentrated factors of the prothrombin complex, administration of vitamin K remedies along with symptomatic therapy. With early diagnosis and prescription of appropriate therapy, prognosis is favorable.

Graphical abstract

Reasons for vitamin K antagonists–dependent coagulopathy cases

Anticoagulant rodenticide intoxication in east China: a three-year analysis

The study was designed to analyze the incidence and pattern of anticoagulant rodenticide intoxication in east China and to discuss strategies of diagnosis based on laboratory analysis experience. A total of 117 patients with anticoagulant rodenticide poisoning confirmed by toxicological analysis in east China were included in this study from 2011 to 2013. The mean concentration of anticoagulant rodenticide, age, and gender of these patients, as well as the mode and type of poisoning, were discussed. The age ranged from less than 1 to 80 years with the feeble preponderance of males (M = 53.0%, F = 47.0%). The 0–9 age group covered the largest ratio of these anticoagulant rodenticide poisoning patients. Accidental or voluntary ingestion seems to be the most common cause of intoxication, with still the poisoning cause being unknown for a large number of positive analyses. Bromadiolone was the most commonly observed anticoagulant rodenticide found in the biological samples, followed by brodifacoum. The concentrations of bromadiolone and brodifacoum that were detected in the first collected whole blood from each patient ranged from 1 to 878 ng/mL (mean 97.9 ng/mL) and from 0.5 to 1566 ng/mL (mean 225.1 ng/mL), respectively. The data analysis shows a high incidence of anticoagulant rodenticide poisoning without awareness of the poisoned subjects, clearly emphasizing the need for toxicological analysis in patients with vitamin K-dependent coagulation disorder and restriction on availability of anticoagulant rodenticide.

Treatment of a long-acting anticoagulant rodenticide poisoning cohort with vitamin K1 during the maintenance period

Currently, there are few guidelines for the use of vitamin K1 in the maintenance treatment of long-acting anticoagulant rodenticide (LAAR) poisonings. We explored factors in the treatment of LAAR poisoning during the maintenance period in order to suggest feasible treatment models.Data from 24 cases of anticoagulant rodenticide poisoning in our hospital were collected from January 2013 to May 2016. The patients' sex, age, coagulation function, total time from poisoning to treatment with vitamin K1 (prehospital time), vitamin K1 sustained treatment time (VKSTT), anticoagulant rodenticide category, and specific poison dosage were collected. Multivariate analysis was used to evaluate the correlation between vitamin K1 dosage and other factors during the maintenance period.Only VKSTT (partial regression coefficient -1.133, 0.59, P = 0.035) had an obvious influence on the therapeutic dose of vitamin K1 required during the maintenance period.After an initial pulse therapy, the bleeding and coagulation functions were stabilized, and the patients were subsequently treated with vitamin K1 during the maintenance period. Over time, the maintenance dose of vitamin K1 (10-120 mg/d, intravenous drip) was gradually decreased and was not related to toxicant concentration.

The emerging threat of superwarfarins: history, detection, mechanisms, and countermeasures

Superwarfarins were developed following the emergence of warfarin resistance in rodents. Compared to warfarin, superwarfarins have much longer half-lives and stronger affinity to vitamin K epoxide reductase and therefore can cause death in warfarin-resistant rodents. By the mid-1970s, the superwarfarins brodifacoum and difenacoum were the most widely used rodenticides throughout the world. Unfortunately, increased use was accompanied by a rise in accidental poisonings, reaching >16,000 per year in the United States. Risk of exposure has become a concern since large quantities, up to hundreds of kilograms of rodent bait, are applied by aerial dispersion over regions with rodent infestations. Reports of intentional use of superwarfarins in civilian and military scenarios raise the specter of larger incidents or mass casualties. Unlike warfarin overdose, for which 1-2 days of treatment with vitamin K is effective, treatment of superwarfarin poisoning with vitamin K is limited by extremely high cost and can require daily treatment for a year or longer. Furthermore, superwarfarins have actions that are independent of their anticoagulant effects, including both vitamin K-dependent and -independent effects, which are not mitigated by vitamin K therapy. In this review, we summarize superwarfarin development, biology and pathophysiology, their threat as weapons, and possible therapeutic approaches.

Structural perturbation of a dipalmitoylphosphatidylcholine (DPPC) bilayer by warfarin and its bolaamphiphilic analogue: A molecular dynamics study

Compounds with nominally similar biological activity may exhibit differential toxicity due to differences in their interactions with cell membranes. Many pharmaceutical compounds are amphiphilic and can be taken up by phospholipid bilayers, interacting strongly with the lipid-aqueous interface whether or not subsequent permeation through the bilayer is possible. Bolaamphiphilic compounds, which possess two hydrophilic ends and a hydrophobic linker, can likewise undergo spontaneous uptake by bilayers. While membrane-spanning bolaamphiphiles can stabilize membranes, small molecules with this characteristic have the potential to create membrane defects via disruption of bilayer structure and dynamics. When compared to the amphiphilic therapeutic anticoagulant, warfarin, the bolaamphiphilic analogue, brodifacoum, exhibits heightened toxicity that goes beyond superior inhibition of the pharmacological target enzyme. We explore, herein, the consequences of anticoagulant accumulation in a dipalmitoylphosphatidylcholine (DPPC) bilayer. Coarse-grained molecular dynamics simulations reveal that permeation of phospholipid bilayers by brodifacoum causes a disruption of membrane barrier function that is driven by the bolaamphiphilic nature and size of this molecule. We find that brodifacoum partitioning into bilayers causes membrane thinning and permeabilization and promotes lipid flip-flop - phenomena that are suspected to play a role in triggering cell death. These phenomena are either absent or less pronounced in the case of the less toxic, amphiphilic compound, warfarin.

Brodifacoum Inhalation and its Clinical Manifestations in a 21-Year-Old Caucasian Man

Exposure to brodifacoum, a superwarfarin substance, can lead to severe coagulopathic manifestations. Brodifacoum is a lipophilic, vitamin K antagonist with a long half-life. Clinical manifestations are challenging to diagnose if the patient cannot provide information regarding exposure. Herein, we report the first case in the literature, to our knowledge, of a patient who had intentionally inhaled brodifacoum. We performed coagulation studies such as prothrombin time (PT) and international normalized ratio (INR) to monitor vitamin K dependent coagulation factors in the patient, a 21-year-old Caucasian man. On admission to the hospital, the INR of the patient was 12.9; a computed tomography (CT) angiogram detected a mediastinal hemorrhage. In the absence of 4-factor PCC, the patient received 30 plasma transfusions during a 4-day period due to persistent left pleural effusions, along with vitamin K therapy to normalize his coagulation factors. His high-performance liquid chromatography (HPLC) results on hospital day 3 and day 26 confirmed the presence of brodifacoum in his body. We believe that inhalation led the poison to bypass the initial metabolism process of the liver, resulting in rapid anticoagulation and subsequent bleeding diathesis. Management of brodifacoum poisoning is case dependent on the amount of exposure and INR status. Constant INR monitoring, large dose vitamin K therapy and initial plasma transfusions (in the absence of PCC) were able to prevent severe internal bleeding in the patient.

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.

Possible unaware intoxication by anticoagulant rodenticide

Superwarfarin toxicity may be a serious problem. It needs high clinical suspicious in patients with bleeding diathesis without hematologic or liver diseases even in patients with apparent negative history of warfarin or other anticoagulant accessibility. Here we reported a patient with a negative history of any medical diseases or drug administration who was referred with generalized ecchymosis. Increased international normalized ratio and decreased vitamin K-dependent coagulation factors were detected in this patient. His hematologic and liver evaluations were normal. Clinical pharmacist emphasis in taking history revealed using anticoagulant rodenticide all over the farm the patient lived in that might result in unaware intoxication in this patient who suffered dementia.

Prolonged coagulopathy after brodifacoum exposure

PURPOSE

A case of brodifacoum exposure leading to coagulopathy lasting for approximately one year despite treatment with large doses of phytonadione is reported.

SUMMARY

A 36-year-old man was diagnosed with severe coagulopathy. He was treated and discharged on 40 mg of oral phytonadione daily. The cause of the coagulopathy remained unknown at discharge, but the hematologist theorized that exposure to a vitamin K antagonist was likely the source of the patient's condition. The patient was rehospitalized one week later with an International Normalized Ratio (INR) of 5.9 despite self-reported medication compliance. Oral phytonadione was increased to 80 mg daily. The patient was seen at an outpatient hematology clinic for several months and continued on tapering dosages of oral phytonadione. A coagulopathy panel from the original hospitalization confirmed the presence of brodifacoum, though the method of exposure remained unclear. He was lost to follow-up until approximately nine months later, when he reported taking 10 mg daily of oral phytonadione and had an INR of 1. Oral phytonadione was discontinued. Two months later, his INR was greater than 9, despite an undetectable level of brodifacoum. He was rehospitalized with oropharyngeal hematoma approximately 1 year after the initial coagulopathy diagnosis. The patient was discharged on 40 mg oral phytonadione daily with outpatient follow-up.

CONCLUSION

A patient with brodifacoum exposure ingested brodifacoum had coagulopathy that lasted approximately one year despite long-term treatment with large dosages of oral phytonadione. The coagulopathy persisted even when brodifacoum was undetectable in the serum. Long-term treatment with high-dose phytonadione is expensive, which may influence medication compliance.

How I treat poisoning with vitamin K antagonists

Severe deficiency of vitamin K-dependent proteins in patients not maintained on vitamin K antagonists is most commonly associated with poisoning by or surreptitious ingestion of warfarin, warfarin-like anticoagulants, or potent rodenticides ("superwarfarins"), such as brodifacoum. Serious bleeding manifestations are common. Superwarfarins are 2 orders of magnitude more potent than warfarin and have a half-life measured in weeks. These rodenticides are readily available household environmental hazards and are sometimes consumed accidentally or as manifestations of psychiatric disease. Immediate diagnosis and proper therapy is critically important to minimize morbidity and mortality because this condition, affecting thousands of patients annually, is reversible. Treatment with large doses of oral vitamin K1, often over months to years, to maintain a near-normal prothrombin time can reverse the coagulopathy associated with superwarfarins. Although these patients initially present to various medical specialties, the hematologist is often consulted to offer the definitive diagnosis and proper therapy.

Evaluation of risk factors in patients with vitamin K-dependent coagulopathy presumed to be caused by exposure to brodifacoum

BACKGROUND/AIMS

Recently, many cases of vitamin K-dependent coagulopathy of unknown origin have been reported. Such patients lack any relevant family history and have no systemic disease, raising suspicion of superwarfarin intoxication. We evaluated individual risk factors causing coagulopathy and hemorrhagic symptoms in patients with suspected superwarfarin intoxication. In addition, we determined how to effectively treat vitamin K-dependent coagulopathy caused by suspected superwarfarin intoxication.

METHODS

Seven patients with suspected superwarfarin intoxication who lacked any definitive history of rodenticide ingestion were included. Thirty-one patients initially diagnosed with rodenticide poisoning were also included. We performed a retrospective chart review of all subjects and examined clinical data including patient demographics and medical histories.

RESULTS

Patients initially diagnosed with rodenticide poisoning were divided into two groups, one of which had a laboratory abnormality (prothrombin time [PT] > 13 seconds) and another group with PTs in the normal range. There was no significant difference between the two groups in any of age, gender, the extent of chronic alcohol consumption, the causative rodenticide, psychiatric problems, ingestion of drugs interacting with warfarin, the extent of intoxication, or the type of ingestion attempt. The albumin level of the former group was significantly lower than that of the latter group (p = 0.014). Furthermore, a significant difference between the two groups was evident in terms of simultaneous ingestion of rodenticide and alcohol (p = 0.023).

CONCLUSIONS

Most patients with superwarfarin poisoning did not exhibit any complication. When such complications were evident, they were associated with serum albumin level and coingestion of rodenticide and alcohol.

Bleeding manifestations apparently unrelated to coagulation or other organic disorders: A tentative classification and diagnostic clues

OBJECTIVE

To study the features of bleeding conditions apparently not associated with vascular, platelet, or clotting dysfunctions.

METHOD

Conditions that may meet these criteria are: Münchausen syndrome factitious or fictitious, suicidal or homicidal bleeding, bleeding due to self-punishment, stigmatization, the battered child syndrome, and psychogenic bleeding.

RESULTS

The importance of these variegate conditions is not trivial in clinical practice. Differential diagnosis may be difficult and involve other specialists besides hematologists. Occasionally, invasive procedures are involved.

DISCUSSION

The occurrence of bleeding in patients, without a clotting defect or a systemic disorder and a negative family history for bleeding represents a diagnostic challenge. A careful examination of the physical and psychological status of the patient and an appropriate evaluation of the environment in which bleeding occurs, is always needed.

Determination of bromadiolone and brodifacoum in human hair by liquid chromatography/tandem mass spectrometry and its application to poisoning cases

RATIONALE

Bromadiolone and brodifacoum, two common anticoagulant rodenticides, are involved in the majority of anticoagulant rodenticide poisoning cases in humans in China. Hair analysis can provide long-term information on drug exposure. A method using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) was developed and validated for the measurement of bromadiolone and brodifacoum in human hair.

METHODS

A 1 mL aliquot of a phosphate buffer solution (pH 6.8) was added to 20 mg of pulverized hair followed by ultrasonication and liquid-liquid extraction. Liquid chromatography was performed using a C(18) column with a mobile phase gradient of ammonium acetate (10 mM) and methanol. A tandem mass spectrometer in multiple reaction monitoring mode with a negative electrospray ionization source was employed for detection. Warfarin-d(5) was used as an internal standard for both analytes.

RESULTS

The limits of detection (LODs) for bromadiolone and brodifacoum were 0.010 and 0.025 ng/mg, respectively. The calibration curves for both analytes were linear from 0.025 to 1 ng/mg. The accuracy ranged from 90.3 to 109.3%, and the intra-day and inter-day imprecisions were less than 15%.

CONCLUSIONS

The established method was found effective when applied to the analyses of bromadiolone or brodifacoum in five cases, indicating that segmental hair analysis could be useful for clinical and forensic purposes by identifying the time of ingestion.

Transitions of care in anticoagulation management for patients with atrial fibrillation

Thromboprophylaxis with oral anticoagulants (OACs) is an important but underused element of atrial fibrillation (AF) treatment. Reduction of stroke risk with anticoagulants comes at the price of increased bleeding risk. Patients with AF receiving anticoagulants require heightened attention with transition from one care setting to another. Patients presenting for emergency care of anticoagulant-related bleeding should be triaged for the severity and source of the bleeding using appropriate measures, such as discontinuing the OAC, administering vitamin K, when appropriate, to reverse warfarin-induced bleeding, or administering clotting factors for emergent bleeding. Reversal of OACs in patients admitted to the hospital for surgery can be managed similarly to patients with bleeding, depending on the urgency of the surgical procedure. Patients with AF who are admitted for conditions unrelated to AF should be assessed for adequacy of stroke risk prophylaxis and bleeding risk. Newly diagnosed AF should be treated in nearly all patients with either warfarin or a newer anticoagulant. Patient education is critically important with all anticoagulants. Close adherence to the prescribed regimen, regular international normalized ratio testing for warfarin, and understanding the stroke risk conferred by both AF and aging are goals for all patients receiving OACs. Detailed handoff from the hospitalist to the patient's primary care physician is required for good continuity of care. Monitoring by an anticoagulation clinic is the best arrangement for most patients. The elderly, or particularly frail or debilitated patients who are transferring to long-term care, need a detailed transfer of information between settings, education for the patient and family, and medication reconciliation. Communication and coordination of care among outpatient, emergency, inpatient, and long-term care settings are vital for patients with AF who are receiving anticoagulants to balance stroke prevention and bleeding risk.

Diffuse alveolar hemorrhage in coumarin users: a fibrosing interstitial pneumonia trigger?

BACKGROUND

Fibrosing interstitial pneumonias (IPs) include idiopathic pulmonary fibrosis (IPF) and nonspecific interstitial pneumonia (NSIP). It has been suggested that oxidative damage plays a role in the pathophysiology of idiopathic interstitial pneumonias. Diffuse alveolar hemorrhage (DAH) can cause oxidative stress. Accordingly, we hypothesized that episodes of DAH might trigger fibrosing IP development.

METHODS

Patients using coumarins with confirmed DAH were retrospectively gathered during a 9 year period and reviewed for the development of IPF or fibrosing NSIP.

RESULTS

A total of 65 patients with DAH could finally be included, 31 (48 %) of whom subsequently developed a fibrosing IP. The majority of these 31 patients developed the fibrosing IP within 3 years after DAH confirmation. A total of 41 (63 %) patients died within 3.0 ± 0.9 (range 1.3-4.7) years after the DAH diagnosis had been confirmed. Twenty-two of the deceased (54 %) had finally developed fibrosing IP.

CONCLUSIONS

Almost half of the patients with established episodes of DAH developed fibrosing IP; therefore it seems that DAH might be a trigger for the development of fibrosing IP. This observation warrants prospective studies to further evaluate the clinical impact of these findings.

Determination of bromadiolone and brodifacoum in human blood using LC-ESI/MS/MS and its application in four superwarfarin poisoning cases

Superwarfarin poisoning is a growing health problem. A sensitive and reproducible LC-ESI/MS/MS (liquid chromatography electrospray ionization tandem mass spectrometry) method was developed and validated for the determination of bromadiolone and brodifacoum, the most commonly used superwarfarins, in human blood using warfarin-D5 as an internal standard. Bromadiolone and brodifacoum were extracted from whole blood samples by liquid-liquid extraction with ethyl acetate. Multiple-reaction monitoring (MRM) was used to detect bromadiolone and brodifacoum using precursor→product ion combinations of m/z 525→250 and 521→135, respectively. The calibration curves were linear (r(2)=0.9999) in the concentration range of 0.5-100.0 ng/mL for bromadiolone and brodifacoum, with a lower limit of detection of 0.1 and 0.2 ng/mL, respectively, in whole blood. This method detected trace levels of bromadiolone and brodifacoum in whole blood samples and can be used in the diagnosis of poisoned human beings.

Development of cocaine-induced interstitial lung damage in two CYP2C and VKORC1 variant allele carriers

BACKGROUND

Often, the connection between drug use and the development of related inflammatory damage or idiosyncratic toxicities is hard to recognize and objectify. The presence of cytochrome P450 (CYP) variant genotypes appears to be a substantial susceptibility risk factor in the development of drug-induced pulmonary adverse events. We hypothesized that the presence of variant alleles may be associated with serious complications of illicit drug use.

CASE REPORT

We report the cases of two cocaine users who developed a 'flu-like' syndrome with diffuse interstitial infiltrates after cocaine abuse. Genotyping for CYP (CYP2C9, CYP2C19) and vitamin K epoxide reductase complex 1 (VKORC1) allelic variants (-1639G/A and 1173C/T) was performed in these two patients. Both cases were heterozygous for VKORC1 variant alleles, and both possessed a CYP2C polymorphism (case 1: CYP2C19*1/*2; case 2: CYP2C9*1/*3).

CONCLUSIONS

The described drug abuse cases suggest that an association between the presence of CYP2C and VKORC1 allelic variants and cocaine-induced interstitial lung damage is highly likely. It is assumed that these polymorphisms contribute to intra-individual variability in drug response and toxicity, including cocaine response and toxicity. Moreover, the importance of including pharmacogenomics in the work-up of patients with suspected drug-induced (lung) toxicity, such as alveolar hemorrhage, is highlighted by these cases.