Toxic Teaser Answers
July 12, 2005
Cynthia Aaron, MD
A call comes in from a hospital concerning a gentleman who has been bitten by a
Brazilian Banana spider. He is complaining of severe limb pain and doesn’t feel
well. Although these spiders are hitchhikers on banana shipments from South
America, this one was running free in his house (by choice…)
What are the signs and symptoms of its envenomation and what would you
advise for treatment?
We saw these things in Mississippi on
deployment. This is a Florida Banana
Spider. It was about 5 inches long
and very pretty and was crawling
through our tent hospital. I picked it
up and took it outside to continue it’s
life cycle-CA
Phoneutria species-although indigenous to central and south America, also exist
in the southeastern USA.
These are neurotoxic and cause significant pain and autonomic symptoms. P.
nigriventer venom activates and delays inactivation of the Na channel, causes
vascular smooth muscle contraction and increasing vacular permeability. Signs
include pain, and paresthesia, edema, and systemic findings such as
tachycardia, vomiting, priapism, and shock. Treatment is supportive (sort of like
a Black Widow) but there is an antivenom for those with extremes of age or
complicating co-morbidities.
Bucaretchi F, de Deus Reinaldo CR, Hyslop S, et. al. A clincio-epidemiological
study of bites by spides of the genus Phoneutria. Rev. Inst. Med. Trop. S. Paulo.
41(1): 17-21, 2000
It turns out that the victim of this bite also keeps tarantulas, scorpions, and
rattlesnakes. When questioned, we are reassured that the rattlesnake is kept
locked up but the other beasties have free reign of the house. The victim was
bitten in his sleep so that he does not know which one got him. What would we
see if he was bitten by the scorpion (assume the standard Centroides) or the
tarantula?
Scorpion: Neurotoxin-severe pain and swelling. Autonomic symptoms include
tachycardia, numbness, difficulty breathing, muscle twitching, and in small
children or the elderly: seizures and respiratory paralysis.
©
2005 Children’s Hospital of Michigan Regional Poison Control Center
4160 John R • Suite 616
Detroit • Michigan • 48201
Tarantulas may cause local pain and reaction but more commonly, the response
is either allergic or urticarial from the small hairs becoming embedded in the skin.
The doctor descirbes a full blown allergic reaction in addition to the limb pain.
Why is this occurring?
Many of the people who keep exotic animals will care for them and handle them
daily. All of these animals, including snakes and spiders, shed skin particles and
other proteinaceous components. The person handling the animal can become
sensitized to these protein-based compounds and develop a subsequent allergic
reaction. This appears to be more common than we initially thought, especially
amongst people who handle snakes. Some of what we may be calling a fullblown envenomation, may actually be anaphylaxis.
These problems are taken directly from the AAPCC Review for CSPIs.
1. What is the concentration (in mg/ml) of a solution containing 2 mEq/ml of
potassium chloride (KCl)
KCl Æ K+ + Clof one)
has a valence of one (each of it’s constituents has a valence
Molecular weight of KCl = 39 + 35.5 = 74.5 (my error on the sheet, I put 75.5)
1 mEq KCl = (74.5) x 1/1000 = 0.0745 g = 74.5 mg
mg = (mEq) x (atomic, molecular or formula weight)
valence
= (2mEq/ml) x 74.5mg
1 valence
= 149 mg/ml
2. How many milliequivalent of potassium chloride are represented in a 15 ml
dose of 10% w/v potassium chloride elixir?
Molecular weight is 74.5
1 mEq = 74.5 mg
15 ml dose of a 10% (w/v) elixir =
10 g = x
100 ml 15 ml
100ml(x) = 150gml
x = 1.5 g = 1500 mg
74.5 mg KCl = 1500 mg KCl
1 mEq
x
74.5 mg KCl (x) = 1500 mg KCl (1 mEq)
x = 20.1 mEq
©
74.5 mg x = 1500 mg mEq
2005 Children’s Hospital of Michigan Regional Poison Control Center
4160 John R • Suite 616
Detroit • Michigan • 48201