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Pesticides include insecticides, herbicides, and rodenticides.1 During
2008, more than 93,000 pesticide exposures were reported to the
Toxic Exposure Surveillance System of the American Association of
Poison Control Centers, with more than 43,000 exposures to children
<6 years of age.2 A total of 13 deaths were
associated with pesticide exposure in 2008.2
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Pesticide intoxication results from intentional, accidental,
and occupational exposures. Pesticides are marketed as multiple
formulations, often under shared brand names; therefore, complex
clinical syndromes can result from exposure to both active and other
ingredients. Management often requires a resource such as
the hazardous materials and toxins database or consultation with
a poison control center. Inert ingredients in proprietary formulations,
such as petroleum distillates, are inert in terms of toxicity to
pests during typical exposures, but can be toxic to humans, especially
with excessive amounts. Pesticides have class-specific toxicities,
and many have both local and systemic effects. Supportive care is
of utmost importance in pesticide poisonings, but for some compounds,
the use of antidotes is essential.
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Chemical insecticides are toxic to the nervous system. Toxicity
may include acute, chronic, and delayed sequelae of acute exposure.
The five major classes of insecticides used today are the organophosphates, carbamates, organochlorines, pyrethroids,
and neonicotinoids. Another compound, N,N-diethyl-3-methylbenzamide
(known as DEET), is marketed as a personal insect repellant (Table 195-1). Organophosphate and carbamate
pesticides are cholinesterase inhibitors that have replaced organochlorine
insecticides because of their improved effectiveness and lack of
persistence in the environment and human tissues. During 2008, more
than 50,000 insecticide exposures were reported to the Toxic Exposure
Surveillance System of the American Association of Poison Control
Centers, with six associated deaths.2 More than
300,000 pesticide-poisoning deaths occur each year worldwide, with
insecticides accounting for the majority of deaths.3
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Commonly used organophosphates include diazinon, acephate, malathion, parathion,
and chlorpyrifos. In addition to their use as insecticides, they
have been used as chemical warfare agents since World War II.4 Sarin
was used in the terrorist attack on the Tokyo subway in 1995.5 Organophosphate
and carbamate compounds are the most common insecticides associated
with systemic illness.6,7 Potency among organophosphates
does vary. Highly potent compounds such as parathion are used primarily
in agriculture. Those of intermediate potency include coumaphos
and trichlorfon, which are used in animal care. Diazinon and chlorpyrifos
were phased out from household use in the U.S. beginning in 2000 due
to neurotoxicity, particularly on the developing brains of children.
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Organophosphate poisoning results primarily from accidental exposure in
the home, recently sprayed or fogged areas using pesticide applicators, agriculture,
industry, and the transport of these products.6 Exposure
to flea-dip products has been reported in pet ...