Massive hymenoptera envenomation in a 3-year-old.

Background: Envenomation by a large number of hymenopterans can cause significant morbidity and mortality due to venom load. We present the first case of massive Hymenoptera envenomation by native US Hymenoptera.

Case: A 3-year-old boy and his family were hiking in Oregon and were attacked by yellow jackets. On emergency department arrival, the child was uncomfortable and vomiting. Vital signs were normal; physical examination showed more than 90 punctate lesions on the head and neck, and 30 below the neck without urticaria. Initial laboratory values were normal except for a white blood cell count of 37,500/μL and mild hypokalemia, including a normal creatinine kinase. Intravenously administered fluids, ondansetron, midazolam, and morphine were given for symptom control.Generalized edema developed 12 hours later and was treated with intravenously administered dexamethasone and diphenhydramine. His creatinine kinase peaked at 2085 U/L after 32 hours. Forty-eight hours after the incident, the child began to take oral fluids with laboratory values returning to normal.

Discussion: Delayed toxic effects of mass envenomation are due to direct toxic effects from the large venom load, with several cases of death reported. All prior cases of mass Hymenoptera envenomation in the United States have involved Africanized "killer" honeybees. Guidelines recommend admitting all pediatric patients sustaining more than 50 stings for 24 hours for laboratory evaluations.

Conclusions: Delayed toxic reaction may be caused by native US species of Hymenoptera. Physicians should be aware that endemic US species can cause this reaction and should have a low threshold to admit pediatric patients with more than 50 stings for 24 hours.