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Difficulty: EasyOccupational and Environmental Exposures

A 42-year-old male agricultural worker is brought to the emergency department by his coworkers due to sudden onset of severe shortness of breath, excessive salivation, and abdominal cramps. His coworkers report he was spraying fields with organophosphate pesticides without wearing appropriate personal protective equipment. On physical examination, his heart rate is 50/min, respiratory rate is 26/min, and blood pressure is 100/60 mm Hg. He has pinpoint pupils, generalized muscle fasciculations, and diffuse wheezing with rhonchi on lung auscultation. Which of the following are the most appropriate next steps in the pharmacological management of this patient's condition? (Select all that apply)

  1. Intravenous atropineAnswer
  2. Intravenous pralidoximeAnswer
  3. C
    Intravenous ceftriaxone and azithromycin
  4. D
    Intravenous furosemide
  5. E
    Intravenous physostigmine

Answer

The correct pharmacological interventions are intravenous atropine and intravenous pralidoxime.
The patient is experiencing a cholinergic crisis due to organophosphate poisoning, characterized by muscarinic (bradycardia, miosis, salivation, wheezing) and nicotinic (muscle fasciculations) overstimulation. The correct pharmacological management requires both intravenous atropine, a competitive muscarinic antagonist that resolves the life-threatening excessive respiratory secretions and bradycardia, and intravenous pralidoxime, which reactivates the acetylcholinesterase enzyme to alleviate nicotinic symptoms like muscle weakness.

Step-by-Step Solution

1
Identify the toxidrome based on the clinical presentation and explicit exposure history.
The patient has bradycardia, miosis, muscle fasciculations, salivation, and bronchorrhea after exposure to agricultural pesticides, indicating a cholinergic crisis due to organophosphate poisoning.
Organophosphates irreversibly inhibit acetylcholinesterase, leading to an accumulation of acetylcholine at muscarinic and nicotinic receptors.
2
Select the appropriate antidotes for cholinergic toxicity.
The indicated treatments are atropine (to reverse muscarinic effects) and pralidoxime (to reactivate the cholinesterase enzyme and reverse nicotinic effects).
Reversing the life-threatening respiratory symptoms requires immediate muscarinic antagonism, while restoring muscle function requires enzyme reactivation.

Key Concept

Organophosphate poisoning presents with cholinergic excess (DUMBELS syndrome); pharmacological management requires both atropine (a muscarinic antagonist) and pralidoxime (a cholinesterase reactivator).
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Topics

Occupational and Environmental Exposures

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