UA Research on Scorpion Antivenom Published in May 14 NEJM

TUCSON, Ariz. --Youngsters suffering severe nerve poisoning following a scorpion sting recover completely and quickly if a scorpion-specific antivenom is administered, according to a study conducted by researchers from The University of Arizona and reported in the May 14 issue of The New England Journal of Medicine.

The article, “Antivenom for Critically Ill Children with Neurotoxicity from Scorpion Stings,” recounts a study of 15 children conducted in Tucson, Ariz., during 2004 and 2005. All of the children had been admitted to a pediatric intensive care unit following a scorpion sting and were experiencing abnormal eye movements, uncontrolled thrashing of limbs and respiratory distress, all symptoms of nerve poisoning caused by the venom of the bark scorpion.

The principal investigator of the study and lead author of the article is Leslie Boyer, MD, director of the VIPER (Venom Immunochemistry, Pharmacology and Emergency Response) Institute at The University of Arizona College of Medicine and medical director of the Arizona Poison and Drug Information Center at the UA College of Pharmacy.

In the study, eight of the children, most of whom were under 6 years, received a scorpion antivenom that is commercially available in Mexico but is considered an investigational drug in the United States and is not approved for general use by the U.S. Food and Drug Administration. The seven other study participants received a placebo (a preparation containing no medication).

The symptoms of nerve poisoning were resolved in all of the children treated with the antivenom in less than four hours, and usually within two hours. The children who received the placebo continued to experience nerve poisoning for four hours or more and required large doses of sedative medication and extended hospitalization.

“This study told us that the dangerous effects of bark scorpion venom can be reversed quickly with the right antivenom,” Dr. Boyer says. “One hundred percent of the children who received it got better very quickly, meaning that using this antivenom in the emergency room will make intensive care treatment unnecessary for most patients. This is particularly important in small Arizona towns without pediatric intensive care units. By avoiding helicopter trips and intensive care stays, we can save lives and keep treatment costs down at the same time.”

Andreas Theodorou, MD, a professor of pediatrics and chief medical officer of University Medical Center in Tucson, was part of the study team.

“This antivenom basically takes symptoms away in a very short time,” Dr. Theodorou says. “What was a life-threatening disease that would put kids in the pediatric ICU has become, for most of them, an outpatient disease.”

The study reported in The New England Journal of Medicine involved Anascorp®, an antivenom made and supplied to the UA at no charge by the pharmaceutical company Instituto Bioclon, headquartered in Mexico City.

The study was funded by a grant from the Office of Orphan Products Development of the FDA. Starting in 2004, additional funding from the State of Arizona has enabled 22 hospitals throughout the state to participate in the study and provide antivenom to their patients.

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Additional background for reporters

Annually, about 8,000 scorpion stings occur in Arizona. Approximately 200 cause serious nerve poisoning and require medical treatment. Nearly all of these patients are young children, whose breathing may be impaired severely by the effects of the scorpion venom on the nerves controlling the respiratory system. A 2-year-old boy from the Globe, Ariz., area died from a scorpion sting in 2002.

Arizona’s bark scorpion and its Mexican “cousins” are the only North American scorpions with venom that can cause significant nerve poisoning in humans. Scorpions are very common throughout Mexico, and antivenom products have been manufactured and used there for decades.

The bark scorpion is not found in most of the United States, with Southern Arizona the main location in this country where scorpion sting is a medical issue. Bark scorpions have been reported in California, Nevada and New Mexico. Scorpions sometimes travel to new locations along with humans, in such things as luggage, packages and cars. Travelers visiting the Southwest often are completely unfamiliar with the effects of scorpion sting. A New York City doctor visiting Phoenix recently with his family learned the efficacy of the scorpion antivenom when his 10-year-old son was stung three times while sleeping in a luxury hotel.

Before 2000, a project at Arizona State University in Tempe produced a scorpion antivenom for use in the state. Supplies of that antivenom dwindled following the researcher’s retirement, running out completely in 2004.

Without antivenom, treatment for nerve poisoning requires intensive supportive care, usually with heavy sedation and sometimes requiring a ventilator.

The study reported in NEJM was conducted at University Medical Center and Tucson Medical Center, both in Tucson.

VIPER Institute at The University of Arizona

http://viper.med.arizona.edu

Authors of The New England Journal of Medicine article:
Leslie Boyer, The University of Arizona, VIPER Institute
Andreas Theodorou, The University of Arizona Department of Pediatrics
Robert Berg, The Children’s Hospital of Philadelphia, Department of Anesthesia and Critical Care Medicine
Joanne Mallie, The University of Arizona, VIPER Institute
• Ariana Chávez-Méndez, Universidad Nacional Autónoma de México
• Walter García-Ubbelohde, Instituto Bioclon SA de CV, Mexico City
Stephen Hardiman, Stephen Hardiman Statistics, New Jersey
Alejandro Alagón, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Moralos

Story posted May 13, 6 p.m.