Treatment of lead and arsenic poisoning in anuric patients - a case report and narrative review of the literature.

BACKGROUND: Heavy metal poisoning can cause debilitating illness if left untreated, and its management in anuric patients poses challenges. Literature with which to guide clinical practice in this area is rather scattered. CASE PRESENTATION: We present a case of symptomatic lead and arsenic poisoning from use of Ayurvedic medicine in a 28-year-old man with end-stage kidney disease on chronic hemodialysis. We describe his treatment course with chelating agents and extracorporeal blood purification, and review the relevant literature to provide general guidance. CONCLUSION: Cumulative clinical experience assists in identifying preferred chelators and modalities of extracorporeal blood purification when managing such patients. However, a larger body of real-world or clinical trial evidence is necessary to inform evidence-based guidelines for the management of heavy metal poisoning in anuric patients.

Prevention and treatment of motion sickness.

Motion sickness is a common syndrome that occurs upon exposure to certain types of motion. It is thought to be caused by conflict between the vestibular, visual, and other proprioceptive systems. Although nausea is the hallmark symptom, it is often preceded by stomach awareness, malaise, drowsiness, and irritability. Early self-diagnosis should be emphasized, and patients should be counseled about behavioral and pharmacologic strategies to prevent motion sickness before traveling. Patients should learn to identify situations that will lead to motion sickness and minimize the amount of unpleasant motion they are exposed to by avoiding difficult conditions while traveling or by positioning themselves in the most stable part of the vehicle. Slow, intermittent exposure to the motion can reduce symptoms. Other behavioral strategies include watching the true visual horizon, steering the vehicle, tilting their head into turns, or lying down with their eyes closed. Patients should also attempt to reduce other sources of physical, mental, and emotional discomfort. Scopolamine is a first-line medication for prevention of motion sickness and should be administered transdermally several hours before the anticipated motion exposure. First-generation antihistamines, although sedating, are also effective. Nonsedating antihistamines, ondansetron, and ginger root are not effective in the prevention and treatment of motion sickness.

North American snake and scorpion envenomations.

Envenomations by snakes and scorpions in North America, although uncommon, do occur, and the victims may seek medical treatment. Combined, snake and scorpion encounters result in more than 25,000 calls a year to poison centers. Although some similarities exist with respect to general signs of envenomation and treatment, specific nuances distinguish the medical care to be anticipated and therapies available. Regardless of geographic practice area, exposures will occur that may result in a significant envenomation. This article provides critical care nurses with fundamental knowledge of varied snake and scorpion envenomation presentations and treatments to assist in optimizing patient outcomes.

Toxicology in the emergency department: a review for the advanced practice nurse.

General assessment, resuscitation strategies, and risk assessment of the poisoned patient are explored in this article, including specific interventions for unresponsive patients and seizures. Sympathomimetic and anticholinergic toxidromes are described in terms of clinical presentation and treatment strategies and are compared with other common toxidromes. Controversies in gastric decontamination are also outlined, including consensus panel and national organizational recommendations. Despite available methods for toxin elimination, advances in medicine, and pharmacotherapy options, the cornerstone of toxicology remains supportive care. The purpose of this article is to equip the advanced practice nurse in the emergency setting with baseline knowledge to provide initial care of the poisoned patient.

Kinetics and efficacy of an organophosphorus hydrolase in a rodent model of methyl-parathion poisoning.

OBJECTIVES: Organophosphorus (OP) pesticides exert a tremendous health burden, particularly in the developing world. Limited resources, the severity of intentional OP ingestions, and a paucity of beneficial therapies all contribute to the morbidity and mortality of this broad class of chemicals. A novel theoretical treatment for OP poisoning is the use of an enzyme to degrade the parent OP in the circulation after poisoning. The aims of this study were to determine the pharmacokinetics and efficacy of an OP hydrolase (OpdA) in a rodent model of severe methyl-parathion poisoning. METHODS: Two animal models were used. First, Wistar rats were administered two different doses of the hydrolase (0.15 and 1.5 mg/kg), and the ex vivo hydrolytic activity of plasma was determined by a fluorometric method. Second, an oral methyl-parathion animal poisoning model was developed to mimic severe human poisoning, and the efficacy of postpoisoning OpdA (as measured by survival to 4 and 24 hours) was determined. RESULTS: The half-life of OpdA in the Wistar rat was dependent on the dose administered and ranged between 45.0 and 57.9 minutes. The poisoning model of three times the lethal dose to 50% of the population (3 x LD(50)) of methyl-parathion resulted in 88% lethality at 4 and 24 hours. Using a single dose of 0.15 mg/kg OpdA 10 minutes after poisoning resulted in 100% survival at 4 hours (p = 0.001 vs. placebo), but 0% at 24 hours postpoisoning (p = NS vs. placebo). CONCLUSIONS: The OP hydrolase OpdA exhibits pharmacokinetics suitable for repeated dosing and increases short-term survival after severe methyl-parathion poisoning.

Respiratory failure following isolated ziprasidone ingestion in a toddler.

Ziprasidone is an atypical antipsychotic approved for the treatment of schizophrenia and bipolar mania in adults and is used off label in children and adolescents. Despite increasing use of ziprasidone in both adult and pediatric populations, there remains a paucity of reports describing unintentional pediatric exposures. The following report describes a patient with isolated ziprasidone ingestion who required intubation secondary to respiratory failure. A 15-month-old previously healthy boy presented to the emergency department shortly after his father found him with approximately five partially dissolved 80-mg ziprasidone tablets in his mouth. The child was flaccid and lethargic with no eye opening, withdrawing from pain only. Two hours after arrival, he developed worsening CNS depression with inability to protect his airway and underwent endotracheal intubation. A serum ziprasidone level was 330 ng/mL by LC/MS. The patient was extubated approximately 14 h later and was discharged from the hospital shortly thereafter in good health without neurological sequelae. Isolated pediatric ingestion of ziprasidone resulting in the need for significant medical intervention has not been previously reported. We report a case of respiratory failure requiring intubation following accidental ziprasidone ingestion with confirmatory serum levels.

Case files of the Medical Toxicology Fellowship at Banner Good Samaritan Medical Center in Phoenix, AZ: a non-warfarin anticoagulant overdose.

A 50-year-old man presented to the emergency department (ED) following an overdose of his "blood thinners." The patient had become increasingly depressed over financial concerns, prompting a suicide attempt. He declined to provide any details regarding his current medications or his past medical history. A review of the computerized medical record, however, revealed he had a Factor V Leiden mutation with multiple venothromboembolic events. He previously had an inferior vena cava filter placed, and had received tissue plasminogen activator (tPA) for a cerebrovascular accident. A toxicology consult was obtained in the ED.

OpdA, a bacterial organophosphorus hydrolase, prevents lethality in rats after poisoning with highly toxic organophosphorus pesticides.

Organophosphorus (OP) pesticides poison more than 3,000,000 people every year in the developing world, mostly through intentional self-poisoning. Advances in medical therapy for OP poisoning have lagged, and current treatment is not highly effective with mortality of up to 40% in even the most advanced Western medical facilities. Administration of a broadly active bacterial OP hydrolase to patients in order to hydrolyze OPs in circulation might allow current therapies to be more effective. The objective of this work was to evaluate the efficacy of a new recombinant bacterial OP hydrolase (OpdA), cloned from Agrobacterium radiobacter, in rat models of two chemically distinct but highly toxic and rapidly acting OP pesticides: dichlorvos and parathion. Without OpdA treatment, median time to death in rats poisoned with 3x LD(50) of dichlorvos or parathion was 6 min and 25.5 min, respectively. Administration of a single dose of OpdA immediately after dichlorvos resulted in 100% survival at 24h, with no additional antidotal therapy. After parathion poisoning, OpdA alone caused only a delay to death. However, an additional two doses of OpdA resulted in 62.5% survival at 24 h after parathion poisoning. In combination with pralidoxime therapy, a single dose of OpdA increased survival to 75% after parathion poisoning. Our results demonstrate that OpdA is able to improve survival after poisoning by two chemically distinct and highly toxic OP pesticides.