Unilateral angioedema.

Angiotensin converting enzyme inhibitor-induced angioedema is typically easily recognizable in the emergency department. Angioedema lateralizing to one side, however, is infrequently reported, rare, and has the same potential of progression to airway compromise. We present of a case of an 80-year-old man with angioedema of the lower lip that had regressed prior to significant progression of right sided angioedema of the tongue and oropharynx.

Forgoing the Folate?-Contemporary Recommendations for Methanol Poisoning and Evidence Review.

Methanol poisonings can produce significant toxicity in humans, including acidosis, blindness, and death. The current mainstay of therapy is alcohol dehydrogenase (ADH) inhibition to prevent formation of formic acid and hemodialysis to correct acidosis and remove both parent compound and toxic metabolite. Folate has been recommended as an adjunctive therapy to increase formic acid oxidation into carbon dioxide and water. We retrospectively reviewed recommendation of folate therapy for methanol poisoning by our regional poison center from 2002 to 2012. One hundred two patients met inclusion criteria. Our findings demonstrate a sharp decline in folate recommendation over the course of the study period (48% vs. 12% during the years 2002-2006 and 2007-2012, respectively), despite similar rates of ADH inhibition, hemodialysis, and serious outcomes. This may be related to the approval of the use of fomepizole in methanol poisoning in 2002, which provides a quicker, more reliable means of ADH inhibition than ethanol infusions. We also provide a review of the available evidence of folate use in methanol poisoning.

Those Salicylate Cases-How Sweet Are They?

Owing to the complex metabolism of salicylates, both hyperglycemia and hypoglycemia have been reported with salicylate poisoning. The aim of this study was to characterize this relationship. Data from the Illinois Poison Center were retrospectively queried over a 5-year period (2008-2012), and patients with a salicylate concentration ≥30 mg/dL were included. Hypoglycemia and hyperglycemia were defined as glucose concentrations <55 and >140 mg/dL, respectively. Of the 160 patients included, most were normoglycemic (81%) and 19% were hyperglycemic. No patient experienced hypoglycemia. Our study indicates that hypoglycemia may be a very rare occurrence in the setting of salicylate poisoning. Clinicians must remain vigilant, regardless of the glucose concentration, when entertaining salicylism as an etiology in appropriate patients.

Digoxin-Specific Antibody Fragment Dosing: A Case Series.

Digoxin-specific antibody fragments (DSFab) are used for the treatment of poisoning by cardiac glycosides, such as pharmaceutical digoxin. Dosing of this therapy for chronic and acute poisonings is based on the steady-state serum concentrations of digoxin, historical data in acute ingestions, or empiric regimens purportedly based on the average requirements. Empiric dosing for adult patients involves utilization of 3-6 vials for chronic poisoning and 10-20 vials for acute poisoning. The aim of this study was to describe the average dosing requirements based on the steady-state serum concentration of digoxin or historical data and compare this with the empiric dosing regimens. We performed a retrospective analysis of cases over an 11-year period presented to the Illinois Poison Center where administration of DSFab was recommended. We identified 140 cases of chronic digoxin poisoning and 26 cases or acute digoxin poisoning for analysis. The average dose of DSFab recommended in the cases of chronic digoxin poisoning was 3.05 vials (SD ± 1.31). The average dose of DSFab recommended in the cases of acute digoxin poisoning was 6.33 vials (SD ± 5.26). These values suggest that empiric dosing regimens may overestimate the need for DSFab in cases of both chronic and acute poisonings of pharmaceutical digoxin.

The toxic trio: valproic acid, lithium, and carbamazepine.

Patients with altered mental status and seizure or psychiatric disease often present with an unclear medication history. Commonly prescribed medications include valproic acid (VPA), lithium (Li), or carbamazepine (CZN) of which the regional poison center (RPC) often recommends obtaining these serum concentrations. Regularly ruling out supratherapeutic concentrations without a known history of ingestion may help direct care. Cases from the RPC coded as VPA, Li, and CZN, from January 1, 2006 to December 31, 2008, were searched. All patients with supratherapeutic concentrations (VPA >100 µg/mL, Li >1.2 mEq/L, and CZN >12 µg/mL) were evaluated for the following criteria: (1) those with altered mental status and an unclear history of seizure or psychiatric disorder and (2) a mediation profile not including VPA, Li, or CZN. Twenty-six patients met the inclusion criteria: 8 patients in the VPA group (113-247 µg/mL; mean, 158), 9 patients in the Li group (1.9-5.2 mEq/L; mean, 2.9), and 9 patients in the CZN group (13.4-38.8 µg/mL; mean, 23.2). All patients survived and were treated with supportive care; however, 1 patient had a Li level of 5.2 mEq/L and received hemodialysis. In altered patients potentially being treated for seizure or psychiatric disorders and unknown ingestions or medication lists, obtaining concentrations of VPA, Li, and CZN may help direct care and provide clinically relevant information. The RPC detected 26 patients with supratherapeutic VPA, Li, or CZN concentrations in patients with potential indications for the agent but no available history of drug ingested or medication list. A prospective study is warranted to evaluate the usefulness of obtaining these concentrations in this patient population.

Hyperinsulin therapy for calcium channel antagonist poisoning: a seven-year retrospective study.

The use of hyperinsulin therapy (HIT) in severe calcium channel antagonist (CCA) poisoning has become a more common therapy within the last decade. The objective of this study is to report 7 years of experience recommending HIT. This was a retrospective chart review utilizing our regional poison center (RPC) data from January 1, 2002, through December 31, 2008. All cases of CCA poisoning receiving HIT were searched. Endpoints included the number of CCA cases utilizing HIT, insulin dose, time of initiation of HIT, patient outcome, adverse events, age, glucose concentration, and lowest systolic blood pressure recorded. Forty-six cases of CCA poisoning were managed with HIT over 7 years. All the patients received standard antidotal therapy (= intravenous fluids, calcium salts, glucagon, and pressors). HIT administration followed our RPC recommendation 23 times (50%), and no hypoglycemic events occurred. Means (age, highest glucose measured, and lowest systolic blood pressure measured) were 51 years, 282 mg/dL, and 74 mm Hg, respectively. Our RPC recommendations for HIT were followed 50% of the time over the last 7 years. In light of the lack of hypoglycemia associated with HIT in our study population, we recommend HIT as an early and safe antidote in significant CCA poisoning.

Delayed elevation in carbamazepine concentrations after overdose: a retrospective poison center study.

An initial carbamazepine concentration may initially be supratherapeutic, therapeutic, or even subtherapeutic only to persist to rise over time. The aim of this study was to report the frequency of toxic carbamazepine concentrations continuing to rise and to estimate how often an initially therapeutic or subtherapeutic concentration misrepresents the potential toxicity of an acute carbamazepine overdose. An 8-year retrospective search of all carbamazepine exposures reported to the Illinois Poison Center (January 1, 2001 through December 31, 2008) was reviewed. Inclusion criteria were acute poisonings with a documented carbamazepine concentration of >12 µg/mL at any time. Those with initial concentrations of >12 µg/mL that subsequently increased over time were recorded. Additionally, those cases that initially had therapeutic (4-12 µg/mL) or subtherapeutic (<4 µg/mL) concentration were identified. Descriptive statistics were used to analyze the data. A total of 1424 cases were reported. Of the 523 patients with documented concentrations of >12 µg/mL, 93 patients (17.8%) had initial carbamazepine concentrations >12 µg/mL and continued to rise. Sixteen patients (3.5%) had initial carbamazepine concentrations that were therapeutic (4-12 µg/mL) and 7 patients (1.3%) had initial carbamazepine concentrations <4 µg/mL before rising >12 µg/mL. Certain patients had progressive decreases in level of consciousness corresponding to increasing carbamazepine concentrations. Additionally, several patients with initial levels of therapeutic or subtherapeutic concentration later became comatose and required ventilator management. Initial serum carbamazepine concentrations can be misleading. Serial measurements documenting a declining carbamazepine concentration or prolonged observation are recommended when managing these overdoses.

Variability in hyperbaric oxygen treatment for acute carbon monoxide poisoning.

CONTEXT: In patients with acute carbon monoxide (CO) poisoning, we have noted wide clinical variability in both criteria for hyperbaric oxygen (HBO2) treatment as well as HBO2 treatment regimens. Our aim was to survey Midwest hyperbaric centers for insight into specific criteria and protocols for treating acute CO toxicity with HBO2. METHODS: Hyperbaric centers were identified from the published list of the Undersea and Hyperbaric Medical Society. Ninety-three centers from nine Midwestern states were contacted via telephone. A standard script was used to minimize surveyor bias. RESULTS: Thirty centers that treat CO poisonings were identified. One did not participate in the study. Nineteen reported a specific level of carboxyhemoglobin (COHb) that served as an independent indication for initiation of HBO2 treatment. Four centers used the COHb level as the exclusive indication for HBO2 treatment. Ten centers relied solely on reported symptoms, while the remaining centers used a combination of symptoms plus COHb levels. There were 19 separate treatment protocols. CONCLUSION: No uniform practice for either the initiation or implementation of HBO2 therapy for CO poisoning exists among U.S. Midwest hyperbaric centers responding to a survey. We see opportunity for specific targeted educational programs as well as further study.

Effect of cyclodextrin infusion in a rat model of verapamil toxicity.

Sulfobutylether-ß-cyclodextrin (SBE-CD) is a pharmaceutical excipient known to bind verapamil. After intravenous administration, clearance of SBE-CD approximates glomerular filtration rate. We hypothesized that SBE-CD would complex with verapamil in vivo, enhance renal elimination, and increase time to death in a rat model of verapamil toxicity. Ten Wistar rats were allocated to control or intervention groups. All received isoflurane anesthesia followed by verapamil infusion (32 mg/kg) over 1 hour. The control group received saline bolus 7.5 mL/kg at 5 minutes. The intervention group received SBE-CD infusion 7.5 mL/kg (2.25 g/kg) at 5 minutes. Heart rate, respiratory rate, oxygen saturation, and temperature were monitored. The primary endpoint was time to death measured separately as time to asystole and time to apnea. There was no benefit derived from cyclodextrin infusion. Average time to death was significantly longer in the control group as measured by time to apnea (P < 0.05). Control group survival was significantly better as measured by time to asystole and time to apnea (Breslow P < 0.05). SBE-CD infusion resulted in a shorter time to death measured by time to apnea and asystole. Preliminary work demonstrated no effect in isoflurane anesthetized rats receiving only SBE-CD bolus. Verapamil poisoned rats treated with 2.25 g/kg of SBE-CD showed increased toxicity. We propose that this effect was related to the large hyperosmolar CD infusion combined with verapamil-induced cardiogenic shock. Additional studies are warranted to clarify the mechanism of increased toxicity in our study and to assess for potential beneficial effects at lower SBE-CD concentrations.

Can acute overdose of metformin lead to lactic acidosis?

INTRODUCTION: Metformin-associated lactic acidosis (MALA) is well described in patients taking therapeutic metformin who develop renal failure or other serious comorbid conditions. Metformin-associated lactic acidosis from acute overdose has also been described in case series but is debated by some clinicians, arguing that metformin overdose does not cause lactic acidosis. Our aim was to perform a multicenter poison control database review to determine if MALA can occur in mono-overdose patients with no comorbid conditions. METHODS: This was a retrospective chart review of the Illinois and Washington Poison Centers between the 2001-2006 and 1999-2006 periods, respectively. Metformin overdoses that were referred to health care facilities were categorized into mono-overdose with or with out MALA and polypharmacy overdose with or without MALA. RESULTS: The overall prevalence of MALA was 14 (3.5%) of 398 cases referred to a health care facility. Metformin-associated lactic acidosis occurred in 9.1% of mono-overdose and in 0.7% of polypharmacy overdose patients referred to health care facilities and was 16% for intentional mono-overdoses. There was one death of 132 mono-overdoses referred to health care facilities. CONCLUSIONS: Apparent metformin mono-overdose is associated with MALA. Dosages that place patients at risk for MALA will require additional study.