Faculty Bibliography

Unadjusted doses of valacyclovir can cause neurotoxicity in patients with chronic kidney disease. There are no well documented reports of valacyclovir or acyclovir toxicity providing pre- and postdialysis concentrations of acyclovir in the blood, dialysate and urine of acutely neurotoxic patients. We report an elderly woman with stage 5 chronic kidney disease who developed neurotoxicity after being prescribed unadjusted doses of valacyclovir and provide measurements of the amount of the drug eliminated through haemodialysis vs. native renal clearance. The patient's estimated body-burden of drug before the first session of dialysis was estimated at 580.3 mg. During the first haemodialysis session acyclovir plasma concentrations decreased from 8.8 to 3.2 mg/L (63.6%). Her body-burden of drug before the second session of haemodialysis was estimated as 131.9 mg. During the 2.5 h of the second dialysis session a total of 66.6 mg was eliminated based on measured dialysate concentrations. Urinary elimination was 17.7 mg over 30 h. Despite minimal urinary elimination her blood concentration fell from 8.8 to 0.88 mg/L with a total of 4.5 h of haemodialysis. Haemodialysis appears to be an effective method of eliminating acyclovir, especially in patients with advanced kidney disease.

A 72 year-old female with past medical history that included anxiety, depression, hypertension, and hyperlipidemia was found unconscious in her bed at home by family members, surrounded by pill bottles and numerous loose baclofen tablets. Emergency medical service (EMS) was activated and responded quickly, finding an unresponsive patient with snoring respirations, clenched jaw, and foamy, bilious emesis with vital signs including tachycardia and hypoxia. Initial attempts at basic airway management were followed by movement to a waiting ambulance, and the arrival of an EMS physician and advanced paramedic. Despite use of sodium bicarbonate and multiple doses of a vasopressor, the patient developed widening QRS complex on electrocardiogram and refractory hypotension. After rapid sequence intubation, aspiration and low-volume gastric lavage was performed with a 34F Edlich tube, resulting in removal of visible pill fragments. Subsequently, the patient's hypotension resolved, and she was transferred to the care of the emergency department in stable condition. Gastric lavage remains clinically indicated for rare cases of recent, potentially lethal ingestions of poisons without effective antidotes, and is a standard component of emergency medicine residency training. The proliferation of EMS fellowship trained physicians suggests that this procedure should be considered an option in highly select cases, and EMS physician vehicles may consider carrying Edlich lavage tubes or similar prepackaged kits.

INTRODUCTION/UNASSIGNED:Despite the widely accepted use of methylthioninium chloride (methylene blue) to treat methemoglobinemia, data regarding clinical outcomes are sparse. We sought to better elucidate the efficacy and tolerability of methylthioninium chloride. METHODS/UNASSIGNED:We identified all cases reported to the New York City Poison Center from 2000 to 2024 in which methylthioninium chloride was administered for methemoglobinemia. We extracted clinical data from these cases, which we assessed using primarily descriptive statistics. RESULTS/UNASSIGNED: = 6). Improvement after administration of methylthioninium chloride was reported in 98% of cases (95% CI: 96-100%). Adverse effects attributable to methylthioninium chloride were reported in nine cases (4.9%; 95% CI: 4.6-5.1%), including one instance of hemolysis. Glucose-6-phosphate dehydrogenase activity was found to be deficient in two of seven patients tested, only one of whom did not improve after methylthioninium chloride. Two deaths occurred in this series, both associated with sodium nitrite exposure. DISCUSSION/UNASSIGNED:Most patients with methemoglobinemia improved after 1-2 mg/kg of methylthioninium chloride, supporting current treatment recommendations. Despite few instances of glucose-6-phosphate dehydrogenase activity testing, major adverse effects attributable to methylthioninium chloride were extremely rare. A relatively large proportion of cases receiving multiple doses were associated with dapsone exposure. CONCLUSIONS/UNASSIGNED:In this series, methylthioninium chloride was both efficacious and well tolerated in patients with methemoglobinemia, with a single dose of 1-2 mg/kg being sufficient to treat most patients.

Poisoning management includes gastrointestinal decontamination strategies to decrease the burden of poison entering the body and change the expected severe toxicity expected to a less toxic, more favourable outcome. Common modalities are orogastric lavage, oral-activated charcoal and whole-bowel irrigation. Endoscopic retrieval and laparotomy are rare options reserved for severe ingestions and body packers. Although supporting data are generally of low quality, gastrointestinal decontamination is likely to improve patient outcome in many situations. Unfortunately, technical limitations and contraindications can explain their infrequent use. Orogastric lavage can be useful for early lethal ingestions, albeit with significant complications such as aspiration and perforation. Activated charcoal cannot adsorb every substance. Usual dosing is 1 g/kg per dose. Whole-bowel irrigation is reserved for charged molecules or substances not adsorbed to activated charcoal but requires intact gut motility. Indications depend on several factors inherent to the ingestion (dose, time, poison) and patient's characteristics. During recent decades, studies of newer pharmaceuticals or modified-release formulations showed that significant amounts of poison, especially pharmacobezoars, persist in the gut hours postingestion, thus are amenable to gastrointestinal decontamination. Improved understanding of gut motility in volunteer studies and overdose showed clinically significant reduction in drug exposure with activated charcoal. The 1-h dogma for gastrointestinal decontamination, especially activated charcoal, is now obsolete. Clinicians must perform a risk assessment for each ingestion to determine the expected benefit at the time of decision-making, choosing the modality to achieve reduction in the toxicity burden while planning for complications or contraindications.

INTRODUCTION/UNASSIGNED:Hemodialysis has an essential role in the treatment of certain poisoned patients, both by enhancing the elimination of select poisons and correcting underlying fluid, electrolyte, and acid-base disturbances. We sought to identify barriers to the performance of hemodialysis when it was recommended by our poison center. METHODS/UNASSIGNED:Data from a single United States poison center were retrospectively queried for adult patients for whom the poison center recommended intermittent hemodialysis for poison removal. The primary outcome was the performance of intermittent hemodialysis within 12 h of the poison center recommendation, which we defined as timely hemodialysis. Univariable and multivariable logistic regressions were performed to assess the effect of the following variables on this outcome: age group, patient sex, time of day of the recommendation, day of week of the recommendation, year of the recommendation, hospital location, and poison category. RESULTS/UNASSIGNED:A total of 535 patient encounters were analyzed. The majority (72%) of patients had intermittent hemodialysis performed within 12 h of when it was recommended. The multivariable analyses showed that the odds of receiving recommended intermittent hemodialysis within 12 h were significantly lower when the recommendation was made during the nighttime (OR: 0.660; 95% CI: 0.442-0.987) compared to daytime and during the weekend (OR: 0.605; 95% CI: 0.398-0.918) compared to weekdays. DISCUSSION/UNASSIGNED:Intermittent hemodialysis is resource-intensive and requires specialized equipment and personnel, which is likely less available outside of regular business hours. This study is limited by its retrospective nature and may not be generalizable to other poison centers. CONCLUSION/UNASSIGNED:Patients for whom our poison center recommended intermittent hemodialysis during non-weekday times had lower odds of receiving timely hemodialysis. Hospital administrators and healthcare providers should be aware of this potential treatment obstacle for poisoned patients and identify the specific barriers involved in order to facilitate timely hemodialysis.

INTRODUCTION/UNASSIGNED:Unfortunately, children are not spared from the devastating effects of the ongoing opioid epidemic. In rare cases, young children exposed to opioids present with unique neuroimaging findings affecting the white matter, reminiscent of what was once seen with diacetylmorphine (heroin)-associated leukoencephalopathy. This constellation of findings is termed the pediatric opioid use-associated neurotoxicity with cerebellar edema (POUNCE) syndrome. CASE SUMMARY/UNASSIGNED:A 31-month-old child was found floppy and unresponsive. Upon hospital arrival, there was right gaze deviation, shaking of the arms and legs, miosis, and bradypnea. Response to naloxone was incomplete, and methadone was confirmed in the child's urine. IMAGES/UNASSIGNED:Magnetic resonance imaging of the brain performed 24 h after admission showed abnormal T2/FLAIR hyperintensity with associated restricted diffusion symmetrically involving the cerebellar hemispheres. CONCLUSION/UNASSIGNED:The imaging findings, although far from pathognomonic, should be recognizable by radiologists and toxicologists when considering possible opioid exposure in a young child.

We report a case of Western Gaboon viper (Bitis rhinoceros) envenomation in which the patient's symptoms progressed despite treatment with North American crotalid antivenom but improved after receiving South African Institute for Medical Research (SAIMR) polyvalent antivenom. A 59-year-old man was hospitalized after reportedly being bitten by a Gaboon viper (Bitis gabonica). On arrival, he had normal vital signs, two puncture wounds on his left hand, and edema distal to the wrist. The hospital contacted the local poison center who conveyed that crotalid antivenom would be ineffective and recommended transfer to a snakebite center for species-appropriate antivenom. However, this recommendation was disregarded. Initial laboratory tests 2 hours after envenomation revealed a platelet count of 77 x 10⁹/L; other parameters were normal. He received six vials of crotalid antivenom (CroFab®) followed by three maintenance doses (total 12 vials). The next morning, swelling had progressed proximal to the elbow and platelets decreased to 37 x 10⁹/L. He was subsequently transferred and received SAIMR polyvalent antivenom. Six hours later, his platelets were 130 x 10⁹/L. The next morning, his swelling had significantly improved. He was discharged the following day. After discharge, it was discovered that the snake was a Bitis rhinoceros. Bitis gabonica and Bitis rhinoceros are popular captive snakes in the United States. Bitis rhinoceros was formerly a sub-species of B. gabonica, and they are often referred to interchangeably. Their venoms cause tissue edema, coagulopathy, and in severe cases, hemorrhage, dysrhythmias, and death. Antivenom is not widely available in the United States often necessitating patient transfer or antivenom delivery. This case addresses the question of whether crotalid antivenom, which is ubiquitous in the United States, can treat B. gabonica and B. rhinoceros envenomations and highlights the need for consultation with a poison center to facilitate administration of species-appropriate antivenom.

INTRODUCTION/UNASSIGNED:The use of the osmol gap as a surrogate marker of toxic alcohol poisoning is common. Unfortunately, many patients with alcoholic ketoacidosis have elevated osmol gaps and are misdiagnosed with toxic alcohol poisoning. We aimed to characterize the range of osmol gaps in patients with alcoholic ketoacidosis. METHODS/UNASSIGNED:This was a retrospective poison center study. Data from 24 years were reviewed using the following case definition of alcoholic ketoacidosis: (1) documented alcohol use disorder; (2) presence of urine or serum ketones or an elevated blood beta-hydroxybutyrate concentration; (3) an anion gap ≥14 mmol/L. Potential cases of alcoholic ketoacidosis that failed to fulfill all three criteria were adjudicated by three toxicologists. Exclusion criteria included (1) detectable toxic alcohol concentration, (2) hemodialysis and/or multiple doses of fomepizole, (3) no osmol gap documented, (4) other diagnoses that lead to a metabolic acidosis. Demographics, pH, anion gap, lactate concentration, and osmol gap were extracted. RESULTS/UNASSIGNED:Of 1,493 patients screened, 55 met criteria for alcoholic ketoacidosis. Sixty-four percent were male, and their median age was 52 years. The median osmol gap was 27 [IQR 18-36]. The largest anion gap was 57 mmol/L, and the lowest pH was 6.8. Forty-five (82%) of the patients with alcoholic ketoacidosis had osmol gaps >10; 38 (69%) had osmol gaps >20; 24 (44%) had osmol gaps >30; 11 (20%) had osmol gaps > 40. DISCUSSION/UNASSIGNED:The large range of osmol gaps in patients with alcoholic ketoacidosis often reaches values associated with toxic alcohol poisoning. The study is limited by the potential for transcribing errors and the inability to identify the cause of the osmol gap. CONCLUSIONS/UNASSIGNED:In this retrospective study, patients with alcoholic ketoacidosis had a median osmol gap of 26. Given that alcoholic ketoacidosis is easily and inexpensively treated, proper identification may prevent costly and invasive treatment directed at toxic alcohol poisoning.