1999 annual report of the American Association of Poison Control Centers Toxic Exposure Surveillance System

Molecular Mechanisms of Acute Organophosphate Nephrotoxicity

Organophosphates (OPs) are toxic chemicals produced by an esterification process and some other routes. They are the main components of herbicides, pesticides, and insecticides and are also widely used in the production of plastics and solvents. Acute or chronic exposure to OPs can manifest in various levels of toxicity to humans, animals, plants, and insects. OPs containing insecticides were widely used in many countries during the 20th century, and some of them continue to be used today. In particular, 36 OPs have been registered in the USA, and all of them have the potential to cause acute and sub-acute toxicity. Renal damage and impairment of kidney function after exposure to OPs, accompanied by the development of clinical manifestations of poisoning back in the early 1990s of the last century, was considered a rare manifestation of their toxicity. However, since the beginning of the 21st century, nephrotoxicity of OPs as a manifestation of delayed toxicity is the subject of greater attention of researchers. In this article, we present a modern view on the molecular pathophysiological mechanisms of acute nephrotoxicity of organophosphate compounds.

Activated Charcoal and Bicarbonate for Aspirin Toxicity: a Retrospective Series

INTRODUCTION

Aspirin overdose causes acid-base disturbances and organ dysfunction. Management is guided by research reported over 50 years ago when chronic aspirin toxicity was common and accounted for significant morbidity. We investigate our experience of aspirin overdose and the effectiveness of charcoal and bicarbonate administration over 20 years.

METHODS

This is a retrospective series of acute aspirin overdose from two toxicology units from January 2000 to September 2019. Acute aspirin ingestions > 3000 mg were identified in each unit's database. Excluded were cases of chronic exposure, hospital presentation > 24 hours after ingestion, and cases without a salicylate concentration. Included in our analysis was demographic data, clinical effects, investigations, complications, and treatment.

RESULTS

There were 132 presentations in 108 patients (79 females (73%)). The median age was 28 years (range: 13-93 years). The median dose ingested was 7750 mg (IQR: 6000-14,400 mg). There were 44 aspirin-only ingestions. Mild toxicity (nausea, vomiting, tinnitus or hyperventilation) occurred in 22 with a median dose of 160 mg/kg. Moderate toxicity (acid-base disturbance, confusion) occurred in 16 with a median ingested dose of 297 mg/kg. There were no cases of severe toxicity (coma or seizures) due to aspirin alone. The median peak salicylate concentration was 276 mg/L (IQR: 175-400 mg/L, range: 14-814 mg/L). There was a moderate association between dose ingested and peak concentration (Pearson r = 0.58; 95% CI 0.45-0.68). Activated charcoal was administered in 36 (27%) cases, which decreased the median peak salicylate concentration (34.2 to 24.8 mg/L/g (difference: 9.4, 95% CI: 1.0-13.1)). Bicarbonate was administered in 34 (26%) presentations, decreasing the median apparent elimination half-life from 13.4 to 9.3 h (difference: 4.2 h, 95% CI: 1.0-6.5 h).

CONCLUSIONS

Acute aspirin overdose caused only mild to moderate effects in this series. Early administration of activated charcoal decreased absorption and use of bicarbonate enhanced elimination.

Learning Curve of Upper Aerodigestive Tract Foreign Body Management for Otorhinolaryngology Residents

INTRODUCTION

Foreign body ingestion is the most common reason for otolaryngology specialist consultations in emergency departments. Among the different types of foreign bodies, fish bones are the most common, particularly in Asian populations. In Taiwan, upper aerodigestive tract foreign bodies (UADT-FBs) are mostly managed by residents in the otorhinolaryngology (ORL) department. Considering the learning curve required for all procedures, different management types between residents, and possible resulting safety issues, this study explored the outcomes of UADT-FB management by residents in different years of ORL training.

MATERIALS AND METHODS

The medical records of 2,283 patients who visited Kaohsiung Veterans General Hospital's Emergency Department for UADT-FB during June 2013-August 2019 were retrospectively reviewed. The reviewed data included the demographic data of enrolled patients, outcomes of foreign body management, and follow-up chart records of the patients.

RESULTS

Among the 2,283 patients, 1,324 (58%) were found to be negative for foreign bodies, and foreign bodies in 951 (41.7%) were removed immediately. In the negative finding (NF) group, 2 (4.9%) patients were later found to be positive for foreign bodies during follow-up in the outpatient department. One (2.4%) patient developed a deep neck infection and esophageal perforation. The percentage of NFs decreased from 62.58% in residents in the first half of their first year (R1a) to 54% for third-year residents (R3). Comparing R1a with R3, the number needed to harm for retained UADT-FBs after patients visited the emergency department was 12.2.

DISCUSSION/CONCLUSION

This study provides data from 1 referral center regarding the management of UADT-FBs. With increasing resident training, the percentage of NFs declined from 62.58 to 54%. Young residents, especially those in the first 6 months of their training, should have senior residents perform a second examination if UADT-FBs are not found in suspected cases.

Epidemiology of fatal snakebites in the United States 1989-2018

BACKGROUND

There are 5000-10,000 snake envenomations annually in the United States. Fortunately, few are fatal. In this study we review the epidemiology of fatal snakebites.

METHODS

Native snakebite cases from the American Association of Poison Control Centers (AAPCC) National Poison Data System from 1989 to 2018 were reviewed. Additional cases that were not reported to the AAPCC were identified by reviewing Wikipedia and by searching PubMed and online news outlets using various combinations of relevant keywords.

RESULTS

We identified 101 fatal bites from native snakes. Rattlesnakes accounted for 74 (90.2%) of the 82 deaths for which the species was known or which occurred where rattlesnakes are the only native crotalids. There were five fatalities attributed to copperheads, two due to cottonmouths, and one caused by an eastern coral snake. Males were disproportionately affected. The median age for victims was 40 years old. In cases for which data were available, many of the snake interactions were intentional, e.g. religious services, animal husbandry, and attempting to kill the snake.

CONCLUSIONS

Death following envenomation from a native U.S. snake is unlikely, particularly if medical attention is sought promptly. Rattlesnake envenomations are more likely to be fatal than bites from other species. Intentionally engaging with a venomous snake raises the risk of incurring a fatal bite, as does concurrent alcohol or drug use. Age less than 12 years old does not appear to be a risk factor for a fatal outcome, while elderly patients may have a slightly increased risk of death.

Intoxication From Accidental Marijuana Ingestion in Pediatric Patients: What May Lie Ahead

Marijuana is the most commonly used illicit drug. In young children, there are relatively few reports in the literature of acute marijuana intoxication. Here, we describe the case of a previously healthy 2-year-old girl who presented with clinical seizures. A urine toxicology screen showed elevated levels of tetrahydrocannabinol. The source of the drug was not identified. After a short stay in the hospital, the patient fully recovered with only supportive measures. In this report, we also summarize all domestic and international cases of marijuana intoxication in children younger than 6 years, in conjunction with the number of exposures in children of similar age identified by the US National Poison Data System. This report highlights what is becoming a more common problem. As cannabis continues to be decriminalized across the United States with its increasingly diverse modes of delivery, the potential for accidental exposure in infants and young children also rises. Clinicians should now routinely consider marijuana intoxication in children who present with acute neurological abnormalities.

Cosmetic-Related Injuries Treated in US Emergency Departments: 2002 to 2016

A retrospective analysis was conducted by using data from the National Electronic Injury Surveillance System for children <5 years who were treated in US emergency departments (EDs) from 2002-2016) for a cosmetic-related injury. An estimated 64 686 (95% confidence interval = 53 037-76 335) children were treated in EDs for cosmetic-related injuries during the 15-year study period. There was no significant change in the rate (slope = 1.1 per 10 000 children per year, P = .95) of injuries over the study period. Injuries were most commonly associated with nail care (28.3%), hair care (27.0%), skin care (25.0%), and fragrance (12.7%) products. Children aged <2 years were most frequently injured (59.3%), and poisoning was the most common diagnosis (86.2%). To our knowledge, this is the first study to use a nationally representative sample to describe the epidemiology of cosmetic-related injuries among children aged <5 years. Unintentional exposure to cosmetics is an important source of injury for young children.

Mushroom poisoning epidemiology in the United States

Ingestion of wild and potentially toxic mushrooms is common in the United States and many other parts of the world. US poison centers have been logging cases of mushroom exposure in The National Poison Data System (NPDS) annual publications for over 30 years. This study compiles and analyzes US mushroom exposures as reported by the NPDS from 1999 to 2016. Over the last 18 years, 133 700 cases (7428/year) of mushroom exposure, mostly by ingestion, have been reported. Cases are most frequently unintentional (83%, P < 0.001); cause no or only minor harm (86%, P < 0.001); and in children <6 years old (62%, P < 0.001). Approximately 704 (39/year) exposures have resulted in major harm. Fifty-two (2.9/year) fatalities have been reported, mostly from cyclopeptide (68-89%)-producing mushrooms ingested by older adults unintentionally. The vast majority of reported ingestions resulted in no or minor harm, although some groups of mushroom toxins or irritants, such as cyclopepides, ibotenic acid, and monomethylhydrazine, have been deadly. Misidentification of edible mushroom species appears to be the most common cause and may be preventable through education.

Theophylline toxicity: An old poisoning for a new generation of physicians

A healthy 4-year-old female presented to the emergency department for vomiting and diarrhea. She was diagnosed with a urinary tract infection, treated with antibiotics and anti-emetics and discharged. Within four hours, her symptoms recurred, followed by decreasing responsiveness and seizures. She had significant hypokalemia, hyperglycemia, and a combined respiratory and metabolic acidosis. A sibling then mentioned that the patient ingested their father's 200 mg sustained-release theophylline tablets the previous morning. A serum theophylline level was immediately ordered and returned >444 μmol/L. The patient was intubated and treated with activated charcoal, antiemetics, potassium and intravenous fluids. She underwent continuous renal replacement therapy and her levels declined over the next 24 hours. She was extubated on hospital day 2 and discharged without sequelae. Theophylline ingestions are rare but potentially very serious. Physicians need to know how to diagnose and treat these ingestions.

Accidental Organophosphate Insecticide Poisoning: a Fatal Child case with Hazards to Emergency Department Staff

A 2-year-old boy was accidentally poisoned by one spoonful of organophosphate insecticide and presented in cardiac arrest. Spontaneous circulation was restored after initial resuscitation and antidote therapy (atropine and pralidoxime) but the boy finally succumbed with multiple complications. We reviewed the literature on the clinical features and management of acute organophosphate poisoning, and the appropriate protective equipment for preventing secondary poisoning of healthcare workers.

A Profile of Calls to a Poison Information Center Regarding Older Adults

Objectives: The authors sought to examine the nature of calls to poison information centers by adults ages 50 and over. Methods: The authors used data from the national Toxic Exposure Surveillance System and conducted a retrospective review of all cases reported to an American Association of Poison Control Centers Certified Regional Poison Information Center in 1998 and 1999 ( N = 6,365). Results: The results indicated that females’ poison experiences were more likely the result of therapeutic error, adverse drug reactions, ingestions, and the acute-on-chronic class. The authors found that older age was inversely associated with acute class, suspected suicide, food poisoning, and inhalation and dermal exposures. Discussion: Older adults are the greatest consumers of over-the-counter drugs, take multiple medications for various medical conditions, and are experiencing biological changes that affect drug metabolism. Older women may be at especially high risk because of high drug use. Poison prevention education should target older adults.

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.

Resource utilization patterns of pediatric esophageal foreign bodies

BACKGROUND

Ingested foreign bodies are a frequent presentation in pediatric emergency departments. Although some pass spontaneously through the gastrointestinal tract, the majority of esophageal-ingested foreign bodies (EFB) require removal.

MATERIALS AND METHODS

Kids' Inpatient Database (1997-2009) was used to identify children (aged <20 y) with EFB (International Classification of Diseases, Ninth Revision, Clinical Modification code 935.1). Multivariate logistic regression analyses were constructed to identify predictors of resource utilization.

RESULTS

Overall, 14,767 EFB cases were identified. Most patients were <5 y of age (72%), boys (57%), and non-Caucasian (55%), with a median (interquartile range) length of stay (LOS) of 1 (1) d, and total charges of $11,003 (8503). A total of 11,180 procedures were performed, most commonly esophagoscopy (77%), followed by bronchoscopy (20%), gastroscopy (2%), and rarely surgery (0.8%). By multivariate logistic regression, increased total charges were associated with a diagnosis of esophageal ulceration (odds ratio [OR] = 1.57), esophagoscopy (OR = 1.42), and bronchoscopy (OR = 1.62), all P < 0.001. Total charges also increased with admission to urban nonteaching hospitals (OR = 1.51) versus urban teaching hospitals, P < 0.001. Prolonged LOS (≥1 d) was associated with admission to a hospital in the Midwest (OR = 3.18) and with esophageal ulceration (OR = 2.11) and esophagoscopy (OR = 1.13), P < 0.03. Boys had higher odds of longer hospitalization (OR = 1.21), P < 0.001. Overall hospital mortality was 0.1% (n = 16).

CONCLUSIONS

Most EFB occur in children <5 y of age. Esophageal ulceration, esophagoscopy, and bronchoscopy are associated with increased total charges. Esophageal ulceration, esophagoscopy, and boys are associated with an increased LOS. Surgery and hospital mortality are both extremely rare in children with EFB.

Ethylene glycol poisoning: a rare but life-threatening cause of metabolic acidosis-a single-centre experience

Background.

Intoxication with ethylene glycol happen all around the world and without rapid recognition and early treatment, mortality from this is high.

Methods.

In our study, we retrospectively analysed six cases of ethylene glycol intoxication in our department. We measured ethylene glycol or glycolate levels, lactate levels and calculated the osmolal and anion gap.

Results.

Data from six patients admitted to the nephrology department between 1999 and 2011 with ethylene glycol poisoning are reported. All patients were men. The mean pH on admission was 7.15 ± 0.20 and the anion and osmolal gap were elevated in five of six patients. Four patients had an acute kidney injury and one patient had an acute-on-chronic kidney injury. All patients survived and after being discharged, two patients required chronic intermittent haemodialysis. Interestingly, at the time of admission, all patients had elevated lactate levels but there was no linear regression between toxic levels and lactate levels and no linear correlation was found between initial lactate levels and anion gap and osmolal gap.

Conclusions.

The initial diagnosis of ethylene glycol poisoning is difficult and poisoning with ethylene glycol is rare but life threatening and needs rapid recognition and early treatment. Therefore, intoxication with ethylene glycol should not be misdiagnosed as lactic acidosis in patients with metabolic acidosis and elevated lactate levels.

Coral snake bites and envenomation in children: a case series

OBJECTIVE

North America is home to 2 families of venomous snakes, Crotalinae (pit viper family) and Elapidae (coral snake family). Although there are several published reports describing and reviewing the management of pit viper snakebites in children, there are no recent similar publications detailing the clinical course and management of coral snake envenomation.

METHODS

Our case series describes the hospital course of children with coral snake bites admitted to our regional pediatric intensive care. We also reviewed prior published case reports of coral snake bites in the United States.

RESULTS

We identified 4 patients with either confirmed or suspected coral snake envenomation from our hospital's records. In 2 cases, the snakebite occurred after apparent provocation. Antivenom was administered to 3 patients. The regional venom response team was consulted for management advice and supplied the antivenom. One patient had a prolonged hospital course, which was complicated by respiratory failure, bulbar palsy, and ataxia. All survived to discharge.

CONCLUSIONS

Admission to pediatric intensive care is warranted after all Eastern coral snake bites. A specialized regional or national venom response team can be a useful resource for management advice and as a source of antivenom.

Yield of chest radiography after removal of esophageal foreign bodies

OBJECTIVES

The aim of this study was to determine the benefit of routine postoperative chest radiography after removal of esophageal foreign bodies in children.

METHODS

Medical records were reviewed of all patients evaluated with an esophageal foreign body at a single children's hospital over 10 years. Operative records and imaging reports were reviewed for evidence of esophageal injury.

RESULTS

Of 803 records identified, 690 were included. All underwent rigid esophagoscopy and foreign body removal. The most common items removed were coins (94%), food boluses (3%), and batteries (2%). The rate of esophageal injury was 1.3% (9 patients). No injuries were identified on chest radiographs done as routine or for concern of injury. Patients with operative findings suggestive of an esophageal injury (n = 105) were significantly more likely to have an injury (8.6% vs 0%, P = .0001). Of the 585 children who did not have physical evidence of injury, 40% (n = 235) received a routine chest radiograph. Regardless of the indication, no injuries were identified on chest films.

CONCLUSIONS

We conclude that intraoperative findings during rigid esophagoscopy suggestive of an injury are predictive of esophageal perforation. Routine chest radiography is not warranted in children who do not meet this criterion. In patients with a concern for injury, we suggest that chest radiography should be deferred in favor of esophagram.

Circumstances and factors associated with accidental deaths among children, adolescents and young adults in Cuiabá, Brazil

CONTEXT AND OBJECTIVE Analysis on accidents from the perspective of population segments shows there is higher incidence among children, adolescents and young adults. Since the characteristics and circunstances of the event are closely related to educational, economic, social and cultural issues, identifying them may contribute towards minimizing the causes, which are often fatal. The aim here was to identify the environmental, chemical, biological and cultural factors associated with deaths due to accidents among children, adolescents and young adults in Cuiabá, in 2009. DESIGN AND SETTING This was a descriptive cross-sectional study conducted in Cuiabá, Mato Grosso, Brazil. RESULTS Thirty-nine accidental deaths of individuals aged 0 to 24 years were examined: 56.4% due to traffic accidents; 25.6%, drowning; 10.3%, aspiration of milk; 5.1%, falls; and 2.6%, accidentally triggering a firearm. Male victims predominated (82.1%). The presence of chemical, environmental and biological risk factors was observed in almost all of the homes. Regarding cultural factors and habits, a large proportion of the families had no idea whether accidents were foreseeable events and others did not believe that the family's habits might favor their occurrence. Delegation of household chores or care of younger siblings to children under the age of 10 was common among the families studied. CONCLUSION The results point towards the need to have safe and healthy behavioral patterns and environments, and to monitor occurrences of accidents, thereby structuring and consolidating the attendance provided for victims.

The role for coagulation markers in mild snakebite envenomations

Introduction

The majority of patients seeking medical treatment for snakebites do not suffer from severe envenomation. However, no guidelines exist for ordering coagulation markers in patients with minimal or moderate envenomation, nor in those who do not receive antivenom. In this study, we sought to determine whether it was possible to limit the practice of ordering coagulation studies to those patients suffering severe envenomation, rattlesnake envenomation, or both.

Methods

A retrospective chart review was performed on all cases of crotalid snakebite presenting to an adult emergency department (ED) from April 1998 to June 2006. Each chart was abstracted for patient's age, gender, type of snake (if known), severity of envenomation at initial presentation, coagulation test results, whether antivenom was administered, and whether the patient was admitted.

Results

Over an approximately 8-year period, 131 snakebite cases presented that met the inclusion criteria, of which 35 (26.7%) had some type of coagulation marker abnormality. Limiting coagulation testing to patients suffering severe envenomation or rattlesnake envenomation would have resulted in failure to identify 89% or 77%, respectively, of the 35 patients who were found to have at least 1 abnormal coagulation marker.

Conclusion

Our study failed to identify a subset of patients that could be defined as low risk or for whom coagulation marker testing could be foregone. This study suggests that coagulation tests should be routinely performed on all patients presenting to the ED with complaints of envenomation by copperheads, moccasins, or rattlesnakes. Further clarification of when coagulation markers are indicated may require a prospective study that standardizes snake identification and the timing of coagulation marker testing.

Anaphylaxis with Latrodectus antivenin resulting in cardiac arrest

Latrodectus mactans antivenin is a safe and effective therapy for severe black widow spider envenomations when given to most patients. We report a case of a 37-year-old male with a history of asthma that was given L. mactans antivenin for symptoms related to a black widow envenomation and developed a severe anaphylactic reaction resulting in cardiac arrest. When traditional therapies failed, the patient was given methylene blue for anaphylactic shock resulting in a 30-h period of hemodynamic stability. Despite initial resuscitation, the patient ultimately died 40 h after presentation. Under the right circumstances, L. mactans antivenin remains a safe and effective therapy for severe black widow envenomations. However, anaphylaxis is a risk for those receiving this therapy, even when the antivenin is diluted and given as an infusion. We report the first death related to diluted L. mactans antivenin given as an infusion.

Frequency and outcomes of accidental ingestion of tobacco products in young children

This review assesses published literature related to frequency and outcomes associated with accidental ingestion of tobacco and pharmaceutical nicotine products among young children. Twenty-seven years of annual reports by American Association of Poison Control Centers (AAPCC) were analyzed for occurrence and outcomes associated with accidental ingestion events involving tobacco and pharmaceutical nicotine products among young children. Over a 27-year period, and of >50 million contacts for all categories combined, 217,340 contacts involving ingestion of tobacco products were reported. Approximately 89% involved children <6 years old. One fatality was reported, however the co-ingestion of both cigarettes and diazepam complicates an assessment of a contributory role of tobacco. The rate of major, non-fatal, outcomes was <0.1%. Data from AAPCC reports and other sources indicate the frequency of accidental poisoning events is relatively low for tobacco products compared with other products such as drugs, dietary supplements, cleaning products, and personal care products. These findings, along with those for pharmaceutical nicotine products, are consistent with published case reports and reviews, indicating that the frequency and severity of outcomes associated with accidental ingestion of tobacco products by young children appear to be relatively low. However, adults should keep tobacco products out of the reach of children.

A randomized multicenter trial of Crotalidae polyvalent immune F(ab) antivenom for the treatment of rattlesnake envenomation in dogs

OBJECTIVE

To determine clinical efficacy of the Crotalidae polyvalent immune F(ab) (ovine) antivenom (OPCA) against progressive crotalid envenomation in the dog as reflected in stabilization or improvement of snakebite severity scores (SSS). Additionally, due to the potential decreased half-life of the F(ab) antibodies in dogs we compared SSS between dogs receiving 2 different dosing regimes.

DESIGN

Prospective, clinical trial.

SETTING

Five veterinary emergency and critical care facilities.

ANIMALS

One hundred and fifteen client-owned Crotalid (rattlesnake) snake bitten dogs in whom worsening of the envenomation syndrome was observed before OPCA treatment.

INTERVENTIONS

In a multicenter randomized clinical trial a single dose (1 vial) of OPCA alone was compared with 2 doses (1/2 vial each) administered 6 hours apart. Standard supportive care was provided in all cases.

MEASUREMENTS AND MAIN RESULTS

Data were available for 115 patients, 9 of which were fatalities. All patients' clinical condition was documented with a standardized SSS system accounting for each major body system. Each fatality received maximum severity scores of 20. The mean severity score of the 115 patients decreased from 4.19 to 3.29 points and there was no difference between the 2 treatment groups. The mean severity score of the 107 patients without fatalities decreased from 4.16 to 2.15. Antivenin-related acute reactions occurred in 6 dogs (6%), and no serum sickness occurred within the 95 cases contacted at the 2-week posttreatment follow-up.

CONCLUSIONS

In the first randomized trial in dogs of antivenin in the United States, OPCA effectively stabilized or terminated venom effects. There were no statistical differences detected between treatment groups within the study time frame.

Suicide by gabapentin overdose

Gabapentin is an antiepileptic drug that is prescribed for both FDA-approved and multiple off-label conditions, and has a relatively safe side-effect profile. Rare cases of overdose-related adverse effects have been reported in the literature. Described herein are the circumstances and autopsy findings of a 62-year-old woman with a history of depression, whose death was caused by intentional ingestion of excess gabapentin. The postmortem peripheral blood gabapentin concentration as determined by high-performance liquid chromatography/tandem mass spectroscopy was 88 μg/mL. Previously reported cases of individuals surviving gabapentin overdoses are discussed and compared with this case. Based on a review of the available literature, this appears to be the first published report of a death due solely to gabapentin toxicity.

Repeated intoxication presenting with azotemia, elevated serum osmolal gap, and metabolic acidosis with high anion gap: differential diagnosis, management, and prognosis

A man with a history of alcoholism presented on two different occasions with mental changes, clinical signs of volume depletion, elevated serum osmolal gap, metabolic acidosis with high anion gap, metabolic alkalosis, hyponatremia, and azotemia after binge drinking of only ethanol. In both episodes, the serum contained ethanol, acetone, and 2-propanol (isopropanol), but no methanol or ethylene glycol. In the first episode, the rates of excretion of acetoacetate and 3-hydroxybutyrate in the urine were greatly increased. Volume repletion was the only treatment. In both episodes, azotemia and metabolic acidosis were rapidly reversed, while modest metabolic alkalosis was noted after treatment. The triad of azotemia, elevated osmolal gap, and high anion gap metabolic acidosis, which characterizes intoxication with methanol or ethylene glycol, can also develop in alcoholic ketoacidosis (AKA), an entity with substantially different management and outcome. Finding 2-propanol in the serum of patients with AKA indicates either concomitant 2-propanol ingestion or formation of 2-propanol from acetone.

Suppression of SLC11A2 expression is essential to maintain duodenal integrity during dietary iron overload

Iron is essential for the survival of mammals, but iron overload causes fibrosis and carcinogenesis. Reduced iron absorption and regulated release into circulation in duodenal mucosa constitute two major mechanisms of protection against dietary iron overload; however, their relative contribution remains elusive. To study the significance of the former process, we generated SLC11A2 transgenic mice (TGs) under the control of the chicken beta-actin promoter. TGs were viable and fertile, and displayed no overt abnormalities up to 20 months. No significant difference in iron concentration was observed in major solid organs between TGs and their wild-type littermates, suggesting that increased number of iron transporters does not lead to increased iron absorption. To test the sensitivity to iron overload, TGs and wild-type mice were fed with an iron-rich diet containing 2% ferric citrate. Iron supplementation caused suppression of endogenous duodenal SLC11A2 expression, down-regulation of duodenal ferroportin, and overexpression of hepatic hepcidin, precluding excessive iron uptake both in the TGs and wild-type mice. However, iron-treated TGs revealed increased mortality, resulting from oxidative mucosal damage leading to hemorrhagic erosion throughout the whole intestinal area. These findings suggest that reduced iron release from duodenal cells into circulation plays a role in mitigating excessive iron uptake from the diet and that finely regulated duodenal absorption is essential to protect intestinal mucosa from iron-induced oxidative damage.

Toxicity from a clonidine suspension

BACKGROUND

Clonidine is frequently prescribed to children. Clonidine overdose in children has resulted in major clinical effects and deaths.

CASE REPORT

A 3.5-year-old male with a history of a seizure disorder and night terrors presented following difficulty walking, excessive sleeping, agitation when awake, and possible seizure activity. Chronic medications were valproic acid (VPA) and clonidine. On presentation, he alternated between poor responsiveness and agitation, with initial vitals: blood pressure, BP 144/76 mmHg; heart rate, 65 bpm; respiratory rate, 18 bpm; temperature 99.5 degrees F; and pulse oximetry 96% on room air. VPA level was 35 microg/mL. A toxicology consult the next day noted a dry mouth, 2-mm pupils, intermittent gasping, and central nervous system (CNS) depression, with a diagnostic impression of clonidine overdose. The caregiver had been giving 1 mL (0.1 mg) qd of a pharmacy-compounded clonidine suspension by a provided syringe. The pharmacy procedure record agreed with the physicians order. The amount dispensed was a 30-day supply but the bottle was empty on day 19, leading us to suspect a possible accelerated dosing error. The concentration in the bottle thus could not be confirmed. The child slowly returned to his baseline state over 48 hours. A serum clonidine level drawn approximately 18 hours after his last dose later returned at 300 ng/mL (reference range = 0.5-4.5 ng/mL).

CASE DISCUSSION

Compounding and liquid dosing errors are common in children and may result in massive overdoses. There was an accelerated dosing error, but whether a compounding or suspension error or even an acute overdose occurred as well is unknown.

CONCLUSION

Particular care should be taken with medications that have low therapeutic indices, that are extemporaneously compounded, and are prepared as liquids, where medication errors are more likely.

Lithium: updated human knowledge using an evidence-based approach: part III: clinical safety

Lithium use in mental diseases has changed over the years but remains a cornerstone of treatment in bipolar disorders. In two companion papers, we have reviewed existing (and especially recent) data on lithium efficacy and updated basic knowledge regarding the practical fundamentals of lithium therapy. The present paper reviews safety data on lithium available to date. Gastrointestinal pain or discomfort, diarrhoea, tremor, polyuria, nocturnal urination, weight gain, oedema, flattening of affect and exacerbation of psoriasis are typical complaints of patients receiving long-term lithium therapy. Renal involvement results in a reduced urinary concentrating capacity, expressed as obligate polyuria, with secondary thirst. With long-term therapy, this may result in nephrogenic diabetes insipidus. In addition, glomerular filtration rate falls slightly in about 20% of patients. The view that only a few patients receiving long-term lithium are at increased risk of glomerular impairment and progressive renal insufficiency should be regarded with caution. The risk is increased in case of concomitant diseases or medications. Lithium treatment may inhibit thyroid hormone release and induce goitre. Consequently, the prevalence of both overt and subclinical hypothyroidism is increased, with circulating thyroid auto-antibodies frequently being found. Much less commonly, thyrotoxicosis may also develop in association with lithium therapy. Long-term lithium treatment may also be associated with persistent hyperparathyroidism and hypercalcaemia, as well as with hypermagnesaemia. Overweight of up to 4-10 kg is found in approximately 30% of lithium-treated patients. Most neurological manifestations are benign, for example, the fine postural and/or action tremor present in 4-20% of patients. This is increased by high caffeine consumption and concomitant use of other psychotropic agents. A number of rare, potentially serious neurological adverse effects have been reported, including extrapyramidal symptoms, 'pseudotumour cerebri' or occasionally cerebellar symptoms. Severe neurological sequelae are exceptional. Cognitive disturbances are often mentioned as a lithium-related adverse effect. The few controlled studies do show a statistically significant negative effect of lithium on memory, vigilance, reaction time and tracking. There are frequent reports of mild effects of lithium on cognition at therapeutic serum concentrations. A number of deaths associated with lithium treatment have been reported. The most serious issue is that of non-accidental overdose, i.e. either long-term overdosage or acute overdose on long-term treatment. Progressive renal insufficiency, an exceptional complication of long-term lithium therapy, may also have a fatal outcome. In relation to pregnancy, lithium salts are rated as category D (positive evidence of risk). Therefore, prescription of lithium should be avoided during the first trimester of pregnancy unless the benefit to the mother exceeds the risk to the fetus. Although lithium transfer into breast milk is well established, the long-term fate of babies breast-fed by mothers receiving lithium therapy is unknown. Whether lithium therapy is safe in breast-feeding women is controversial. Although there is no absolute contraindication, it is known that the kidney is particularly sensitive to lithium just after birth. Intoxication in patients on long-term treatment with lithium in the absence of history of acute ingestion is not rare. Contributing factors include change in daily dose, long-term high dosage, kidney disease or drug interaction. In suspected cases, serum concentrations should be obtained early and repeatedly. In addition to supportive measures, haemodialysis is the treatment of choice for severe cases. Thorough knowledge of the limitations and drawbacks of lithium therapy is mandatory for its optimal use, especially at a time when its risk/benefit profile needs to be compared accurately with that of antiepileptic drugs and other mood stabilizing medications.

Homicidal poisoning deaths in the United States 1999-2005

OBJECTIVES

Homicidal poisoning is an intriguing but poorly described phenomenon. This study describes homicidal poisoning deaths in the United States during 1999-2005.

METHODS

A trend analysis of homicidal poisoning death was performed using Vital Statistics data. The National Mortality Statistics database was queried using "homicide" as injury intent and "poisoning" as mechanism for the years 1999-2005. Counts and rates were obtained for subgrouping by using demographic data and ICD-10 codes. Chi-square analysis calculated subgroup odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

A total of 523 homicidal poisoning deaths were identified. The overall rate for the period was 0.26/million/year. Males were significantly (OR 1.34, CI 1.13-1.59) more likely to victims than females. Death was more likely at extremes of age. Rates were 2.05/million (OR 8.72, CI 6.63-11.49) in children <1 year and 0.56/million (OR 2.20, CI 1.38-3.52) at ages >or=85 years. Rates also varied by race and were more common among Blacks (0.43/million; OR 1.83, CI 1.47-2.26). The greatest rate was observed in Black infants (5.3/million; OR 21.34, CI 14.17-32.15). ICD-10 codes indicated that medications were the most common poison. Rates were significantly higher in the West and lower in the Northeast.

CONCLUSION

The overall homicidal poisoning death rate was low between 1999 and 2005. The most common type of poison used was medications. Substantially higher rates were observed in vulnerable populations at extremes of age, particularly infants, and among Blacks. This challenges common notions of the victims of homicidal poisoning and the underlying motivation of their poisoners.

The state of dietary supplement adverse event reporting in the United States

PURPOSE

The Dietary Supplements Information Expert Committee (DSI-EC; the Committee) of the United States Pharmacopeial Convention (USP) reviews safety profiles of dietary supplements before development of USP-National Formulary (USP-NF) quality monographs. Because the veracity of dietary supplement adverse event reports (DS AERs) directly affects DSI-EC safety reviews, the Committee reviewed the current status of DS AER reporting in the US.

METHODS

DSI-EC reviewed PubMed searches, information from the US Food and Drug Administration's (FDA) MedWatch program, the Toxic Exposure Surveillance System (TESS) of the American Association of Poison Control Centers (AAPCC), and reports from US and other agencies. DSI-EC analyzed this information to identify key factors that affect the quality of DS AERs.

RESULTS

The overall incidence of DS AERs appears generally to be low. However, the primary reporting portal (FDA MedWatch) receives fewer AERs than do poison control centers (PCCs), and limited coordination exists among national and international surveillance programs for evaluating signals that may indicate potential public health risks. Both inadequate and poor-quality reporting of DS AERs are major limitations of DS safety monitoring in the US.

CONCLUSIONS

Based on its assessments, the Committee advances recommendations to improve the quality of reporting, monitoring, and assessing DS AERs. These include (1) enhanced data collection approaches, (2) improved coordination of AER surveillance programs, (3) strengthening of educational programs for public and health care sectors, and (4) conduct of research concerning the safety of DS. If taken, these approaches are expected to improve the health and well-being of DS users.

Trends in emergency department use of gastric lavage for poisoning events in the United States, 1993–2003

OBJECTIVE

To determine current trends in the use of gastric decontamination for the emergency department (ED) treatment of overdose patients.

METHODS

In the National Health Ambulatory Medical Care Survey (NHAMCS), a weighted sampling of U.S. EDs, overdose-related visits were examined using ICD-9 CM E codes and NHAMCS' "reason-for-visit" classification.

RESULTS

From 1993 to 2003 there were an estimated 11.68 million ED-treated poisoning events. Some 13.7% of those treated were lavaged. Rates fell significantly, from an annual average of 18.7% of cases during 1993-97 to 10.3% during 1998-2003 (p < 0.001). Controlling for year, urgency, and admission status in multivariate logistic modeling, lavage was significantly and positively associated with private insurance payor status, younger age (<30), female gender, white race, 8 PM-8 AM presentation, and intentional rather than unintentional overdose.

CONCLUSION

ED use of gastric lavage in poisoned patients has decreased significantly over the past decade but varies by demographic and non-clinical factors.

Simple diagnostic tests to detect toxic alcohol intoxications

Methanol, ethylene glycol, and diethylene glycol intoxications can produce visual disturbances, neurologic disturbances, acute renal failure, pulmonary dysfunction, cardiac dysfunction, metabolic acidosis, and death. Metabolic acidosis and an increased serum osmolality are important clues to their diagnosis. The former reflects the organic acids produced by metabolism of the parent alcohol, whereas the latter is caused by accumulation of the offending alcohol. However, neither the clinical nor the laboratory findings are specific for toxic alcohol ingestions. The definitive diagnosis of the alcohol intoxications is commonly based on detection of the alcohol or its metabolites in blood. Early diagnosis is important, because initiation of appropriate treatment can markedly decrease their rates of morbidity and mortality. Currently, detection of the parent alcohol in body fluids is inferred from its measurement in blood. This measurement is often performed by specialty laboratories using expensive equipment, and a long delay between obtaining the specimen and getting the results is not unusual. In this report, we describe liquid-based tests that detect methanol, ethylene glycol, diethylene glycol, and ethanol in saliva. The tests are sensitive, and they have different specificity for each of the alcohols facilitating distinction among them. The relatively high sensitivity and specificity of the tests as a whole will facilitate the rapid diagnosis of each of these alcohol intoxications.

Selective serotonin re-uptake inhibitor warnings and trends in exposures reported to poison control centres in Texas

OBJECTIVES

Since January 2002, the US Food and Drug Administration (FDA) has issued a number of advisories about the use of antidepressants, including selective serotonin re-uptake inhibitors (SSRIs). These advisories may have influenced the number of SSRI exposures reported to poison control centres. The purpose of this study was to examine time trends in SSRI exposures reported to poison control centres in Texas with respect to the timing of the various advisories.

STUDY DESIGN

Retrospective review of data from poison control centres.

METHODS

Cases were divided into two groups: (1) paroxetine exposures and (2) other SSRI exposures reported to poison control centres in Texas between 1998 and 2006. The month and year of the call, and patient age and gender were identified. The mean monthly number of ingestions for the two groups was calculated for six time periods related to the FDA advisories.

RESULTS

The mean monthly number of total paroxetine ingestions between January 2002 and June 2003 was 77.6. This declined by 23.3% to 59.6 in July 2003-March 2004 after an advisory about the risk of suicidality in youths using paroxetine. Comparable mean monthly numbers for patients aged <20 years were 33.3 and 20.3, respectively (decline of 38.9%); and for patients aged >or=20 years were 44.0 and 38.6, respectively (decline of 12.4%). Mean monthly numbers for total other SSRI ingestions were 206.4 and 243.1, respectively (increase of 17.8%).

CONCLUSIONS

The FDA advisory in June 2003 appeared to initiate a decline in paroxetine ingestions, particularly among patients aged <20 years, but did not appear to influence other SSRI ingestions reported to poison control centres in Texas.

Verapamil toxicity dysregulates the phosphatidylinositol 3-kinase pathway

OBJECTIVES

Recent animal research and clinical case reports suggest benefit from high-dose insulin therapy (HDIT) for the treatment of calcium channel blocker (CCB) toxicity. One molecular signaling pathway, the phosphatidylinositol 3-kinase (PI3K) pathway, that contributes to CCB toxicity and the efficacy of HDIT, was examined for a role in this phenomenon.

METHODS

A differentiated 3T3-L1 adipocyte model system was utilized to characterize metabolic and molecular signaling events dysregulated in response to acute CCB toxicity. Glucose uptake assays were performed in the presence of representatives of three classes of CCB drugs, and the ability of HDIT to reverse observed inhibition was assessed. Western blot analyses were utilized to probe which insulin-dependent signaling pathway was inhibited by CCB toxicity.

RESULTS

Representative compounds from the dihydropyridine and phenylalkylamine classes of CCBs were more effective at inhibiting glucose uptake in differentiated 3T3-L1 adipocytes than a representative from the benzothiazepine class. Phosphorylation at serine 473 of the Akt protein (P-Akt), a protein representing a common pathway for insulin receptors (IR), insulinlike growth factor receptors (IGFR), and hybrid receptors formed by IR and IGFR subunits, was abolished in the presence of toxic doses of the phenylalkylamine CCB verapamil. Phosphorylation at serine 473 of Akt was rescued in the presence high concentrations of insulin.

CONCLUSIONS

These data suggest that dysregulation of the insulin-dependent PI3K pathway is partially responsible for insulin resistance and the hyperglycemic state observed in response to acute CCB toxicity.

Detoxication treatment for carbamazepine and lithium overdose

This article reports detoxication treatments of a case of combined overdose of carbamazepine and lithium in a 38-year-old female with bipolar disorder. She was brought to the emergency unit after the family found her unresponsive and lying near empty packages for carbamazepine (corresponded to 7.7 g) and lithium carbonate (corresponded to 6.6 g) tablets. On admission, her blood pressure, heart rate and respiratory rate were 80/55 mmHg, 90 per minute and 13 per minute, respectively. Her GCS was 3 (E1, M1, V1). She received gastric lavage after intratracheal intubation, followed by administration of activated charcoal via gastric tube, and a large volume (800 ml/h) of lactate Ringer's solution by intravenous infusion. The serum levels of carbamazepine and lithium approximately 5 h after ingestion were 56.0 mug/ml and 3.56 mEq/l, respectively. The carbamazepine overdose was mainly treated by a 3 h charcoal hemoperfusion (CHP). The CHP treatment decreased serum carbamazepine levels by approximately 30-40% as compared with the levels simulated by Bayesian analysis using 1-point or 2-points serum level(s) (without detoxication treatment). For lithium overdose continuous infusion of Ringer's solution was effective, which increased serum sodium gradually and facilitated the elimination of lithium. In conclusion, the treatments with CHP and continuous infusion of Ringer's solution were considered to be effective for detoxification of carbamazepine and lithium overdose, respectively, when compared with those drug levels without detoxication treatment that simulated by Bayesian analysis method.

Pyrethrin and pyrethroid exposures in the United States: a longitudinal analysis of incidents reported to poison centers

INTRODUCTION

Citing the Food Quality Protection Act, the US Environmental Protection Agency (EPA) decided to phase out and eliminate organophosphate insecticide use in residential environments. The phase out process spanned from 2000 to 2005, and it may have resulted in increased consumer use of insecticides containing other active ingredients. This study utilized data from the national Poison Control Center to assess possible changes in exposure incidents involving pyrethrin and pyrethroid insecticides during the phase out of organophosphates from residential uses.

METHODS

We extracted pyrethrin and pyrethroid insecticide exposure data from the American Association of Poison Control Centers Toxic Exposure Surveillance System (TESS) annual reports from 2000 to 2005. We examined pyrethrin and pyrethroid incidents by total exposures for each year, and we stratified exposures by age range, reason, number of cases treated in a health care facility, and medical outcome. Cases were examined as a proportion of all insecticide exposures. We calculated the annual incidence rates for exposures involving pyrethrin and pyrethroid insecticides of the population served.

RESULTS

Pyrethrin and pyrethroid exposures increased annually in number and as a percentage of all insecticide exposure incidents. The increase in cases was observed for all age categories and exposure reasons. A statistically significant correlation was observed between advancing years (2000-2005) and the number of pyrethrin and pyrethroid incidents (p<.01). While the number of incidents treated in a health care facility increased annually during the study period, the proportion was constant (0.185 +/- 0.012) over the six year period. During the study period, the incidence rate for pyrethrin and pyrethroid exposures increased each year. 44% of all medical outcomes data was recorded, and the majority of outcomes resulted in no symptoms (37%) or minor symptoms (53%).

CONCLUSION

TESS data showed a clear increase in cases involving pyrethrins and pyrethroids. The increase was temporally associated with the phase out of organophosphates from residential uses. In the future, medical toxicologists and poison control center personnel should be prepared to respond to an increasing number of pyrethrin and pyrethroid insecticide exposures.