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32 Cards in this Set
- Front
- Back
How does Rosen's classify pesticides?
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Organophosphates and Carbamates
Chlorinated Hydrocarbons Substituted Phenols Chlorophenoxy compounds Bipyridyl compoundsPyrethrins and Pyrethroids |
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How do organophosphates cause toxicity?
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Inhibition of acetylcholinesterase causing the buildup of acetylcholine with a cholinergic toxidrome that can weirdly have normo or tachycardia secondary to nicotinic stimulation.
Also causes seizures and respiratory arrest (hyperstimulation -> paralysis) |
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What is the cholinergic toxidrome?
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SLUDGE
Salivation Lacrimation Urination Defication Gastrointestinal cramps Emesis and the killer B's Bradycardia, Bronchorrhea, Bronchospasm |
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How do organophosphates affect the nicotinic receptors?
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Hyperstimulation causes twitches/fasciculations/reflexes -> muscle fatigue/paralysis -> respiratory insufficiency
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What is "aging" in the context of organophosphate poisoning?
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Over time OP's cause irreversible conformational change to the acetylcholinesterase enzyme preventing reconstitution of the enzyme by an oxime antidote.
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How can decreased cholinesterase activity be diagnosed?
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Plasma and erythrocyte cholinesterase levels. Plasma levels drop and recover fast. Erythrocyte levels are indicative of what is happening at the nerve terminal. They recover 1%/d if untreated.
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How is organophosphate poisoning treated?
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Decontamination, supportive care, and reversal of acetylcholine excess / toxin binding.
LOTS of atropine to treat symptoms Pralidoxime to regenerate acetylcholinesterase |
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Should succinylcholine be used for intubation?
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No. It is broken down by acetylcholinesterase so it will have a really long half-life
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What is the dose of atropine used to treat organophosphate poisoning?
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1-2mg IV doubled every 5 minutes until secretions clear
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Does atropine work on the nicotinic sites?
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No. Therefore it does not reverse the skeletal muscle effects
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How does pralidoxime treat organophosphate toxicity?
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It restores the cholinesterase activity to muscarinic and nicotinic sites
Dose is 1-2g IV q4-8h over 30-60 minutes and then an infusion |
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What nerve agents are related to organophosphates? Why are they so toxic?
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Sarin & VX
They age very quickly |
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Contrast carbamates with organophosphates?
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They have a shorter duration of action and their beinding to cholinesterase is reversible.
They probably do not require pralidoxime but it is difficult to distinguish from OP poisoning |
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Why are chlorinated hydrocarbons evil?
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These insecticides stick around for pretty much ever and have bad ecological consequences.
They stick around inside us forever because they are super lipophilic. |
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Where are chlorinated hydrocarbons still used?
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On people!
Lindane aka Kwell is a lice and scabies treatment. It's not first-line though and is banned some places. |
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How do chlorinated hydrocarbons cause toxicity?
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They cause neuronal irritability
They are carcinogenic |
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How does acute chlorinated hydrocarbon toxicity present?
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Seizures, tremors, paresthesias, altered mental status, muscle twitching
Hyperthermia, rhabdomyolysis, ATN Ventricular arrhythmias |
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How is acute chlorinated hydrocarbon toxicity managed?
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Control seizures with benzo's
Acute cardiac monitoring +/- beta blockers Cooling for hyperthermia Fluids for rhabdomyolysis Dialysis and other elimination methods do not work |
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Name a substituted phenol.
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Dinitrophenol
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How do substituted phenols cause toxicity?
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They uncouple oxidative phosphorylation causing a damaging hyperthermia and some cause methemoglobinemia
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How is substituted phenol toxicity treated?
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Fluids, cooling, benzo's
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What is the most famous chlorophenoxy compound?
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Agent Orange
2,4 D and 2,4,5 T are herbicides |
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How does chlorophenoxy toxicity present?
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Dermal/GI irritation, N/V
Muscle fasciculations May uncouple oxidative phosphorylation -> hyperthermia and rhabdomyolysis -> renal/hepatic failure |
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How is chlorophenoxy toxicity treated?
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Supportive management
Decontamination Cool |
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Name a bipyridyl compound.
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Paraquat and diquat (the latter is sometimes in Roundup)
They are herbicides that are activated when exposed to sunlight. |
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How does bipyridyl toxicity cause damage?
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They produce super-oxides and cause lipid peroxidations causing ++ GI damage when ingested (esoph perf's)
Paraquat causes the most damage to the lungs -> surfactant loss, pulmonary fibrosis, ARDS and respiratory failure. Diquat acts more on the kidneys |
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Are AC, GL, WBI, dialysis effective for bipyridyl toxicity?
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GL maybe
AC is if early enough *NOTE* Dialysis works |
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What product is glyphosate found in?
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Roundup
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What is glyphosate?
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The isopropyl ammonium salt of a noncholinesterase inhibiting OP herbicide
Humans do not have the enzyme that it works on. |
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How does glyphosate toxicity present?
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Basically only presents with caustic ingestion and GI distress. Drinking a lot could cause liver/heart/kidney effects. Aspirating would cause pulmonary irritation and would be bad.
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How is glyphosate toxicity treated?
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Supportive
Tube/vent may be required if aspirated. Endoscopy for GI exposure. |
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How does DEET toxicity present?
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Toxicity can occur with high concentrations, repetitive application or GI ingestion.
Can cause contact dermatitis, liver dysfunction and neurologic findings (admit neuro symptoms). Asymptomatic patients should be observed x 4-6h |