Multiple people in a small town began experiencing abdominal cramps, excessive salivation and urination, and muscle twitching shortly after a small crop duster plane made several passes over the community. As you are assessing the patients, you further determine that most of them are bradycardic and have miosis. In addition to high-flow oxygen, the most appropriate treatment for these patients includes:
Select one:
A. ?atropine and pralidoxime chloride.
B. ?epinephrine and hyperbaric oxygen.
C. ?amyl nitrate and naloxone.
D. ?activated charcoal and glucose.
The correct answer and explanation is:
Correct Answer: A. Atropine and pralidoxime chloride
Explanation:
The symptoms described—abdominal cramps, excessive salivation and urination, muscle twitching, bradycardia, and miosis (pinpoint pupils)—are consistent with cholinergic toxicity. This condition results from excessive stimulation of the parasympathetic nervous system due to the inhibition of acetylcholinesterase, an enzyme that breaks down acetylcholine. The likely cause in this scenario is organophosphate or carbamate poisoning, which can occur through exposure to pesticides, such as those sprayed from a crop duster.
Pathophysiology:
Organophosphates and carbamates inhibit acetylcholinesterase, leading to an accumulation of acetylcholine at synapses. This overstimulation of muscarinic and nicotinic receptors results in the characteristic “SLUDGE” symptoms:
- Salivation
- Lacrimation (tearing)
- Urination
- Diarrhea
- Gastrointestinal cramping
- Emesis (vomiting)
Additionally, overstimulation of nicotinic receptors can cause muscle twitching, weakness, and potentially paralysis.
Treatment:
The mainstay of treatment for cholinergic toxicity is:
- Atropine:
- A competitive antagonist of muscarinic acetylcholine receptors.
- It alleviates symptoms by blocking the effects of excessive acetylcholine, reducing bronchial secretions, salivation, and bradycardia.
- Pralidoxime chloride (2-PAM):
- Reactivates acetylcholinesterase by cleaving the bond between the enzyme and the organophosphate (if administered early).
- Most effective when given within hours of exposure.
Supportive Care:
- Administer high-flow oxygen for hypoxia due to bronchoconstriction and increased secretions.
- Decontaminate the skin and clothing to prevent further absorption.
Incorrect Options:
- B. Epinephrine and hyperbaric oxygen: Useful in anaphylaxis or carbon monoxide poisoning, not cholinergic toxicity.
- C. Amyl nitrate and naloxone: Used for cyanide poisoning and opioid overdose, respectively.
- D. Activated charcoal and glucose: Inappropriate for organophosphate poisoning and ineffective for systemic effects.
Thus, atropine and pralidoxime chloride are the most appropriate treatments.