Review Questions on Organophosphates ORGANIC PHOSPHATE INSECTICIDES are irreversible inhibitors of cholinesterase. The symptoms of OP insecticide poisoning will be constricted pupils, excessive salivation, sweating, fasciculation of the eyelids, tongue, face and neck muscles, weakness, confusion, convulsions, nausea, cramps, diarrhea blurred vision, and finally respiratory failure. Treatment is atropine and 2-PAM (pralidoxime). Normally, atropine is very toxic, but when dealing with organophosphate insecticide poisoning, you may give as much as two grams over a day. Atropine will block the parasympathetic and central effects of the excess acetylcholine. 2-PAM if given early, reactivates the cholinesterase enzyme. 1. Organophosphate anticholinesterases that are employed as insecticides are absorbed after topical application are not available to the general public may produce a marked pupillary constriction are not inactivated by alkali Correct. Partly. Partly. No. The first and third foils are correct. Organophosphate insecticides are widely used today because they do not persist in the environment and they have an extremely low carcinogenic potential. The reason they don't persist in the environment is that they are readily inactivated by the alkaline state of the soil. However, they do have some disadvantages such as their high acute toxicity in man and their high lipid solubility which permits absorption after topical exposure. 2. Signs and symptoms of organophosphorus insecticide poisoning usually do not occur in less than 18 hours after exposure. True. False. Correct. No. The answer is B. Signs and symptoms of organophosphate poisoning rapidly follow systemic absorption by any route. They appear most rapidly after inhalation of vapors or aerosols, where severe effects are present within a few minutes. 3. Atropine is useful in treating poisoning produced by organophosphate insecticides because it reactivates inhibited acetylcholinesterase stimulates alpha receptors directly stimulates beta receptors directly inhibits normal ganglionic transmission blocks the action of acetylcholine at both central and peripheral sites Correct. No. The answer is E. Atropine is a very useful antidote for the treatment of organophosphate poisoning because it blocks both the peripheral and central muscarinic actions of acetylcholine. However, it does not block the nicotinic actions of acetylcholine. Also, for severe central involvement, scopolamine or benactyzine are more useful because they penetrate the blood-brain barrier more easily than atropine. 4. Parathion intoxication inhibits cholinesterases throughout the body must be inhaled as vapor or swallowed as liquid to be effective since skin absorption is negligible initial effects are similar to overactivity of the parasympathetic nervous system causes a reversible inhibition of cholinesterase Correct. Partly. Partly. No. The first and third foils are correct. Parathion, itself, is not a cholinesterase inhibitor but it is converted to paraoxon in the body which is an irreversible inhibitor of cholinesterases. 5. Antidotal therapy includes administration of atropine and pralidoxime (2-PAM) lead poisoning mercury poisoning chlorinated hydrocarbon insecticide poisoning organophosphate ester poisoning carbon monoxide poisoning Correct. No. The answer is D. 6. Parathion poisoning is best treated by dimercaprol nitrite calcium disodium edetate (CaNa2EDTA) atropine disulfiram Correct. No. The answer is D. 7. In poisoning by organophosphates, treatment with atropine will release acetylcholine reactivate cholinesterase prevent all CNS toxicity prevent neuromuscular paralysis none of the above Correct. No. The answer is E. Atropine blocks muscarinic receptors and only reverses the muscarinic effects associated with increased acetylcholine levels. 8. Symptoms of organophosphate poisoning include pinpoint pupils sympathomimetic effects salivation psychotic delusions Correct. Partly. Parlty. No. The first and third foils are correct. Symptoms of organophosphate poisoning are parasympathomimetic NOTsympathomimetic. A 17 year old boy was soaked with 45 percent parathion solution while unloading a spray rig. He showered and went home. Three hours later, he developed nausea and vomiting, pin point pupils and salivation. When brought to the emergency room he was convulsing, incontinent, and was not breathing. 9. Which of the following treatment procedures should be instituted first? give atropine and 2-PAM start IV and administer vasopressors remove clothing and decontaminate skin start artificial respiration give barbiturates or other anticonvulsants Correct. No. The answer is D. The onset of organophosphate poisoning is slowest when absorbed by the percutaneous route. With this patient, the most important emergency procedure is to start artificial respiration. Then, if you are sure that the individual is poisoned with an organophosphate, the antidotes atropine and 2-PAM may be given. 10. Salivation, lacrimation, urination, defecation, muscle twitches, and respiratory depression represent a particular syndrome which may be caused by an overdose of neostigmine may result from organophosphate insecticide poisoning occurs with poisoning by anticholinesterase agents A and C all of the above Correct. No. The answer is E. These are symptoms of parasympathomimetic activation which may be elicited by either carbamate (eg. neostigmine) or organophosphate (eg. parathion) cholinesterase inhibitors. The following cholinesterase inhibitors are used as insecticides ORGANOPHOSPHATES CARBAMATES parathion carbaryl methylparathion baygon malathion methamyl dipterex aldicarb azinphosmethyl disulfoton diazinon ethion 11. Improves skeletal muscle function in anticholinesterase intoxication atropine pralidoxime both neither Correct. No. The answer is B. Skeletal muscle problems in a person poisoned with cholinesterase inhibitors are due to nicotinic effects which are not blocked by atropine. To combat these effects pralidoxime (2-PAM) is administered. 2-PAM reactivates the phosphorylated acetylcholinesterase. 12. DDT (chlorophenothane) is more soluble in lipid than in water is excreted in milk causes convulsions in toxic doses is resistant to biodegradation Correct. Partly. All foils are correct. Because of its lipid solubility and resistance to biodegradation, DDT persists in the environment and is concentrated in the food chain. Therefore DDT, has been replaced by the more toxic organophosphates as commonly used insecticides. 13. A child who has ingested an insecticide containing malathion will have each of the following symptoms except muscular fasciculations abdominal cramps spasm of accommodation dry skin watery nasal discharge Correct. No. The answer is D. The child will be profusely sweating and therefore would NOT have DRY skin. 14. Organophosphorus cholinesterase inhibitors are effective as chemical warfare agents because organophosphorus cholinesterase inhibitors are highly lipid soluble and can be absorbed readily through the skin and lungs. True. False. Correct. No. The answer is A. The following are organophosphate cholinesterase inhibitors classified as chemical warfare agents. They are commonly referred to as "NERVE GAS": Soman, Tabun, Sarin. A 4 year old girl drank an unknown quantity of an insect spray from a coke bottle found in a garage. She vomited on the way to the hospital and had a convulsive seizure. On admission, she was in coma and had respiratory problems. 15. Specific treatment for organophosphate insecticide poisoning should not be started until blood cholinesterase activity has been determined. True False. Correct. No. The answer is B. A 4 year old girl drank an unknown quantity of an insect spray from a coke bottle found in a garage. She vomited on the way to the hospital and had a convulsive seizure. On admission, she was in coma and had respiratory problems. 16. Amyl nitrite by inhalation followed by I.V. sodium nitrite should be given immediately to this child. True. False. Correct. No. The answer is B. A 4 year old girl drank an unknown quantity of an insect spray from a coke bottle found in a garage. She vomited on the way to the hospital and had a convulsive seizure. On admission, she was in coma and had respiratory problems. 17. A normal value for blood cholinesterase would be strong evidence against organophosphate poisoning in this girl. Correct. No. The answer is A. A 4 year old girl drank an unknown quantity of an insect spray from a coke bottle found in a garage. She vomited on the way to the hospital and had a convulsive seizure. On admission, she was in coma and had respiratory problems. 18. The symptoms of organophosphate poisoning usually begin within 12 hours after exposure to the organic phosphate insecticide. Correct. No. The answer is A. This patient should be immediately placed on an artificial respirator. If other symptoms strongly suggest cholinesterase inhibition, atropine should be administered immediately since it will take several hours before lab data is available regarding cholinesterase.The onset of organophosphate poisoning symptoms depends on the route of exposure and the quanity ingested. If some one drank an insecticide spray, the symptoms would certainly occur within 12 hours if they are going to occur at all.