0071643192.pdf

(Barré) #1

ENVIRONMENTAL EMERGENCIES


Bees
■ Barbed stingers →stinger remains in victim (one sting/bee).
■ The process kills the bee.
■ Killer bees have similar toxin potency but attack in large numbers →
greater overall venom load.
■ Venom contains proteins and enzymes (histamine, bradykinin, etc.).

Wasps
■ Nonbarbed stinger →can sting multiple times.
■ Similar venom to bees

Fire ants
■ Small and light reddish-brown to brown
■ Contain unique alkaloid venom
In general, three types of reactions are possible:
■ Local toxic reaction
■ Allergic reaction
■ Serum sickness

MECHANISM OFTOXICITY
■ Local reaction to venom
■ Exposure to venom in sensitized individual →mast cell degranulation →
allergic reaction.
■ Each species has unique antigens.
■ Development of delayed (type III) immune response →systemic symp-
toms and rash (serum sickness).

SYMPTOMS/EXAM
■ Local reaction
■ Bees and wasps: Irritation, itching, and redness at sting site that may
last for 2–3 days
■ Fire ants: Intense burning, papules that may turn to sterile pustules in
24 hours
■ Allergic reaction
■ Ranging from diffuse pruritus and urticaria to anaphylaxis
■ Vast majority occur within 30 minutes
■ Serum sickness
■ Onset of symptoms 7–10 days after the sting
■ Fever, arthralgias, and malaise (flulike symptoms)
■ Rash (most commonly angioedema/urticaria)

TREATMENT
■ Local wound care and tetanus prophylaxis
■ Remove stingers by fastest means possible to reduce venom exposure.
■ Oral antihistamine
■ Treat anaphylaxis
■ Provide Rx for EpiPen if severe allergic reaction (up to 60% recurrence
with future exposure).

Bark Scorpion Sting

Most U.S. scorpion species are not highly toxic and stings result in local pain
only. Pancreatitis is associated with one species (Tityus trinitatus).

Serum sickness is a delayed
immune response occurring
7 – 10 days after antigen
exposure.

Three possible reactions to
hymenoptera envenomation:
■Local toxic reaction
■Allergic reaction
■Serum sickness
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