1
CREEPY CRAWLERS...
BITES & STINGS OF VENOMOUS ARTHROPODS
Robert Norris, MD, FACEP
Wilderness Medical Society
Associate Professor, Surgery
Snowmass, Colorado
Chief, Division of Emergency Medicine
July 24, 2005
Stanford University Medical Center
I. Objectives:
Following this presentation, participants will be able to:
- identify the most dangerous arthropods in the U.S..
- discuss appropriate first aid measures and hospital management for arthropod bites and stings.
II. Introduction:
- the most dangerous creatures on the planet (by # of deaths)
- in 1993, 72,637 calls to 64 poison control centers regarding bites or stings - most due to arthropods
III. Hymenoptera: (Apids [Bees], Vespids [Wasps, Hornets, Yellow Jackets], Fire Ants)
- 2 million people in U.S. allergic to hymenoptera (40-150 deaths/yr)
- anaphylaxis occurs in 0.4% of population
- venoms: vasoactive amines (histamine, serotonin, acetylcholine, epinephrine, norepinephrine,
dopamine), peptides (melittin, apamin), enzymes (phospholipase A, hyaluronidase)
- highly allergenic; variable cross-reactivity (greatest between wasp & yellow jacket)
A.
Reactions:
1.
Normal/Local:
-
pain,
edema,
erythema
-
Management:
-
?
Sawyer
"Extractor"
- remove stinger prn and A.S.A.P. (?scraping vs pulling out?)
-
ice,
antihistamines
(H1
&/or
H2), splint, elevate, update tetanus prn
- if large reaction (> 10 cm diameter): consider steroids
2.
Systemic/Allergic:
- usually mild in children (hives, edema)
-
may
be
severe:
urticaria,
weakness,
dizziness, hypotension, stridor, bronchospasm, nausea/
vomiting, abdominal cramps, loss of consciousness
- may progress rapidly (death in minutes)
-
Management:
- ABC's; IV (fluids); O
2
; monitors; ice
- Epi (1:1,000) - 0.01cc/kg SQ or IM (up to 0.5cc) (further dilute 1:10 and give IV if extremis - rarely
required)
-
antihistamines
(H1
&
H2
blockers)
- steroids
-
bronchodilators
-
pressors
prn
3.
Toxic:
- rare; requires multiple stings (major concern with Africanized honeybees - "Killer Bees"; estimated
lethal dose approximately 19 stings/kg body weight)
- similar findings to anaphylaxis, but more GI complaints and no urticaria or bronchospasm
-
Management: supportive (treat in similar fashion to anaphylaxis)
