Self-assessment
1.
Which of the following is not a potential symptom or sign of exposure to organophosphate
pesticides?
A.
B.
C.
D.
E.
miosis
salivation
lacrimation
constipation
emesis
Correct Answer: D. Signs and symptoms of organophosphate poisoning are best remembered by
the acronym DUMBELS: D-diarrhea, U-urination, M-miosis, B-bronchorrhea, E-emesis, Llacrimation, S-salivation.
2.
Which of the following statements concerning cholinesterase testing for suspected
organophosphate poisoning is false?
A.
B.
C.
D.
E.
Plasma cholinesterase levels are more readily available in hospital laboratories than RBC
cholinesterase levels.
Plasma cholinesterase regenerates more quickly than RBC cholinesterase.
RBC cholinesterase levels have more interindividual variation than plasma cholinesterase
levels.
Plasma cholinesterase levels may be altered by the presence of liver disease or
pregnancy.
Plasma cholinesterase enzyme is found in both the liver and plasma.
Correct Answer: C. Plasma cholinesterase levels are influenced by things such as liver disease,
pregnancy, and estrogen use. Therefore, their levels show a high degree of interindividual
variation. RBC levels show some degree of interindividual variation due to differences in Hgb
levels.
3.
Which of the following general statements regarding organophosphate poisoning is false?
A.
B.
C.
D.
E.
Because of the high risk for potential exposure to patient care staff, attempts to
decontaminate the skin of a suspected victim of organophosphate poisoning should be
avoided.
Organophosphate poisoning may be more difficult to diagnose in pediatric patients.
RBC and plasma cholinesterase levels are the diagnostics tests of choice for suspected
organophosphate poisoning.
Potential causes for respiratory distress in organophosphate poisoning include:
bronchorrhea, bronchoconstriction and respiratory muscle weakness.
Gut decontamination with activated charcoal is useful following acute organophosphate
ingestion.
Correct Answer: A. Because continued exposure to the victim can result from residual
organophosphate pesticide on the skin, decontamination with soap and water is essential. Rubber
gloves should be worn by all treating personnel prior to completion of decontamination as vinyl or
latex gloves offer no significant protection.
4.
Which of the following statements regarding the treatment of organophosphate poisoning is
incorrect?
A.
B.
C.
Atropine administered intravenously reverses the muscarinic effects of acetylcholine.
Signs of atropine toxicity include fever, muscle fibrillations and delirium.
Drying of mucosal and bronchial secretions is a primary endpoint for atropine therapy.
D.
E.
Pralidoxime is used to reverse nicotinic effects resulting from organophosphate poisoning
Pralidoxime may effectively be administered up to 5 days following organophosphate
poisoning.
Correct Answer: E. Pralidoxime should be administered within 48 hours of the expected
poisoning. Beyond this time the enzyme becomes resistant to reactivation due to “aging,” a
stabilization of the AchE-phosphate bond.
5.
Which of the following statements regarding methylparathion is false?
A.
B.
C.
D.
E.
It is primarily used for aerial crop spraying.
Its half-life after indoor spraying is about the same as its half-life outdoors.
Outbreaks of organophosphate poisoning have occurred due to illegal indoor spraying of
methylparathion.
Though studies have been conducted, the long-term effects of acute overexposure to
methylparathion are not well known.
Because pesticide poisoning may be a sentinel public health event, suspected cases
should be reported to the appropriate public health agencies.
Correct Answer: B. Due to breakdown by water and UV light, the half-life of methylparathion
outdoors is about 48 hours. Indoors, it can persist up to 250 days.