pesticide exposure leads to cholinergic poisoning

This patient is exhibiting many of the clinical characteristics of cholinergic poisoning, likely related to carbamate pesticide exposure. Proper management of severe poisoning includes supportive measures, high doses of atropine, and diazepam and pralidoxime.

Cholinergic poisoning can be caused by organophosphate pesticides; military nerve agents; and many medications, including neostigmine and physostigmine. Organophosphates act by inhibiting acetylcholinesterase at neural junctions. Exposed humans can have prominent CNS and autonomic nervous system effects. In many cases, muscarinic, nicotinic, and CNS effects are apparent.

Parasympathetic overstimulation via muscarinic receptors causes excessive salivation, lacrimation, urination, defecation, gastric cramping, and emesis (hence the mnemonic SLUDGE), as well as miosis, bronchorrhea, bronchospasm, and bradycardia. Nicotinic stimulation causes diaphoresis and in rare cases tachycardia, and stimulation of the neuromuscular junction can produce fasciculations, weakness, and paralysis. Coma and seizures are common CNS manifestations. Early death can occur from cardiovascular collapse and/or respiratory failure driven by bronchospasm, exuberant airway secretions, and muscle weakness.

In addition to mechanical ventilatory support, early cardiopulmonary stability can be achieved by high doses of atropine, often necessarily repeated at frequent intervals because of a relative resistance to the drug’s action. Atropine may also be required for protracted periods of time until normal neurological function is restored. Diazepam or another benzodiazepine is recommended because of the muscle abnormalities and high likelihood of seizures complicating severe poisoning. Pralidoxime is an oxime acetylcholinesterase reactivator and should be administered in the setting of nerve gas or pesticide poisoning with severe features. 123

Footnotes

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  2. Eddleston M, Chowdhury FR. Pharmacological treatment of organophosphorus insecticide poisoning: the old and the (possible) new. Br J Clin Pharmacol. 2016;81(3):462-470. PubMed ↩

  3. Henretig FM, Kirk MA, McKay CA Jr. Hazardous chemical emergencies and poisonings. N Engl J Med. 2019;380(17):1638-1655. PubMed ↩