Two Cases of Refractory Cardiogenic Shock Secondary to Bupropion Successfully Treated with Veno-Arterial Extracorporeal Membrane Oxygenation.

Bupropion inhibits the uptake of dopamine and norepinephrine. Clinical effects in overdose include seizure, status epilepticus, tachycardia, arrhythmias, and cardiogenic shock. We report two cases of severe bupropion toxicity resulting in refractory cardiogenic shock, cardiac arrest, and repeated seizures treated successfully. Patients with cardiovascular failure related to poisoning may particularly benefit from extracorporeal membrane oxygenation (ECMO). These are the first cases of bupropion toxicity treated with veno-arterial EMCO (VA-ECMO) in which bupropion toxicity is supported by confirmatory testing. Both cases demonstrate the effectiveness of VA-ECMO in poisoned patients with severe cardiogenic shock or cardiopulmonary failure.

Hypertonic sodium bicarbonate for Taxus media-induced cardiac toxicity in swine.

OBJECTIVE: To determine whether intravenous (IV) hypertonic sodium bicarbonate is effective in the reversal of QRS widening associated with severe Taxus intoxication. METHODS: Seventeen anesthetized and instrumented swine were poisoned with an IV extract of Taxus media until doubling of the QRS interval on electrocardiography was achieved. After poisoning (time zero), the animals received either 4 mL/kg IV 8.4% sodium bicarbonate (experimental group; 6 animals), a similar volume of 0.7% NaCl in 10% mannitol (mannitol group; 6 animals), or nothing (control group; 5 animals). The main outcome parameter was QRS duration. Secondary outcome parameters were mean arterial pressure (MAP), heart rate (HR), and cardiac index (CI = cardiac output/kg). Additionally, arterial pH, partial pressure of carbon dioxide (pCO(2)), and plasma-ionized calcium, sodium, and potassium were monitored. RESULTS: Taxus toxicity, defined as a 100% increase in QRS duration, was produced in all animals. The animals were similar in regard to baseline and time 0 physiologic parameters as well as amount of Taxus media extract administered. From times 5 through 30 minutes, following assigned treatment, significant increases in QRS duration were detected in the experimental and mannitol groups compared with the control group. A significant lowering of MAP was found in the experimental group compared with the control group. No significant difference between groups was noted in HR or CI. The swine treated with hypertonic sodium bicarbonate had a statistically significant increase in pH, plasma sodium concentration, and base excess compared with the other groups. CONCLUSIONS: Hypertonic sodium bicarbonate was ineffective in reversing the widening of QRS interval associated with Taxus poisoning in this swine model.

Respiratory compromise in patients with rattlesnake envenomation.

Respiratory compromise after rattlesnake envenomation (RSE) is an uncommon yet potentially lethal complication. We were interested in determining the frequency of respiratory compromise in patients treated for RSE. The incidence and indications for intubation were also determined. A retrospective chart review was conducted of all patients treated by medical toxicologists at a tertiary referral hospital between July, 1994 and November, 2000. Out of 294 total patients, 289 charts were reviewed. Of all 289 patients, 214 (74%) received Crotalidae Polyvalent Antivenin (Wyeth-Ayerst) and 23 (8%) had clinical evidence of respiratory compromise. Thirteen of 289 patients (4.4%) were intubated following RSE. No one was intubated for antivenin-induced complications. There were no deaths among studied patients during acute hospitalization. Respiratory compromise following RSE is rare, occurring in only 8% of studied patients. Only 2 patients (0.7%) required intubation as a direct consequence of RSE. No one required intubation for antivenin-induced hypersensitivity reactions.

Mycetism: a review of the recent literature.

Approximately 100 of the known species of mushrooms are poisonous to humans. New toxic mushroom species continue to be identified. Some species initially classified as edible are later reclassified as toxic. This results in a continually expanding list of toxic mushrooms. As new toxic species are identified, some classic teachings about mycetism no longer hold true. As more toxic mushrooms are identified and more toxic syndromes are reported, older classification systems fail to effectively accommodate mycetism. This review provides an update of myscetism and classifies mushroom poisonings by the primary organ system affected, permitting expansion, as new, toxic mushroom species are discovered.

A case of neurotoxicity following envenomation by the Sidewinder rattlesnake, Crotalus cerastes.

INTRODUCTION: North American rattlesnake envenomations typically result in local tissue injury and hematologic derangements. Neurotoxicity is uncommon but when present often manifests as fasciculations and paresthesias. Neurotoxicity following Sidewinder (Crotalus cerastes) envenomation has not been previously reported. CASE REPORT: A 56-year-old man bitten on the right foot developed painful paresthesias, weakness and fasciculations of the right lower extremity, and involuntary muscle contractions of the anterior thigh. Local tissue effects and hemotoxicity never developed. The patient was discharged 5 days after the bite with resolution of fasciculations but continued to have right-sided weakness. The snake was identified as a Sidewinder, C. cerastes, by the patient and two independent herpetologists. CONCLUSION: This is the first reported case of a Sidewinder rattlesnake envenomation resulting in neurotoxicity.

Hemodialysis treatment of monomorphic ventricular tachycardia associated with chronic lithium toxicity.

INTRODUCTION: A patient with chronic lithium toxicity developed a life-threatening ventricular arrhythmia that resolved during removal of lithium by hemodialysis. Chronic lithium toxicity commonly results from diminished elimination and can produce neurotoxicity. Cardiovascular complications have been reported and generally affect the sinoatrial node and produce bradyarrhythmias. The majority of these arrhythmias require no emergent intervention. Ventricular arrhythmias associated with lithium toxicity are occasionally mentioned in the literature, but actual cases are rarely reported. CASE REPORT: A 74-year-old man was brought into the emergency department with a 3-day history of progressive encephalopathy, tremor, and weakness. The lithium level was elevated at 2.2 mmol/L, with a normal serum potassium. Electrocardiography revealed nonsustained monomorphic ventricular tachycardia (120-130 beats/min) lasting up to 1 min, alternating with sinus bradycardia and wandering atrial pacemaker. Episodes of monomorphic ventricular tachycardia recurred >100 times. The patient required a norepinephrine infusion for hypotension. Emergent hemodialysis was initiated to remove lithium and to treat the monomorphic ventricular tachycardia, which was felt to be secondary to lithium toxicity. Episodes of monomorphic ventricular tachycardia abated as hemodialysis progressed. The episodes resolved completely within 4 h of initiating hemodialysis. The patient was discharged home in sinus rhythm on day 5. Lithium was not reinstated. CONCLUSION: Monomorphic ventricular tachycardia associated with chronic lithium toxicity is exceptionally rare. Hemodialysis is a treatment option.

Airway compromise after first rattlesnake envenomation.

The purpose of this report is to describe an unusual presentation of anaphylaxis after first-time rattlesnake envenomation. A patient on a medical toxicology inpatient service is presented who had signs of anaphylaxis, including airway compromise, after first-time rattlesnake envenomation. An epinephrine drip and oral intubation were initiated. This case is unusual in that dermal and gastrointestinal exposure may have been the primary sensitization process that preceded a severe anaphylactic reaction after envenomation. The patient's recovery was prolonged. In conclusion, rattlesnake envenomation may result in rapidly progressive airway compromise, possibly caused by anaphylaxis in patients with previous dermal or gastrointestinal exposure to snake proteins.

Initial postmarketing experience with crotalidae polyvalent immune Fab for treatment of rattlesnake envenomation.

STUDY OBJECTIVE: We describe our postmarketing experience with patients receiving Crotalidae polyvalent immune Fab (CroFab; FabAV) antivenom for treatment of rattlesnake envenomation. METHODS: The charts of 28 patients admitted between March 1 and September 9, 2001, with rattlesnake envenomation and treated with FabAV were reviewed for demographic information, time until antivenom treatment, laboratory findings, evidence of hypersensitivity reaction, length of hospital stay, and readmission to the hospital. RESULTS: All patients had swelling, 20 patients had elevated prothrombin times (>14 seconds), 12 patients had low fibrinogen levels (<170 mg/dL), and 6 patients had thrombocytopenia (platelet count <120,000/mm(3)) on presentation. The total dose of FabAV ranged from 10 to 47 vials per patient. Hypofibrinogenemia was resistant to FabAV in some patients. On follow-up, recurrence of coagulopathy was detected in 3 patients, and recurrence of thrombocytopenia was detected in 1 patient. Two patients demonstrated delayed-onset severe thrombocytopenia. Recurrence or delayed-onset toxicity might have been underestimated because of incomplete follow-up in some patients. No acute hypersensitivity reactions occurred. Two patients reported mild symptoms of possible serum sickness on follow-up. CONCLUSION: FabAV effectively controlled the effects of envenomation; however, initial control of coagulopathy was difficult to achieve in some cases, and recurrence or delayed-onset hematotoxicity was common. When initially managing hematotoxicity, a trend toward normalization of laboratory values might be a more reasonable end point for FabAV treatment than attainment of normal reference values in nonbleeding patients.