Organophosphate Poisoning

Organophosphate compounds (insecticides, nerve agents) irreversibly inhibit acetylcholinesterase at cholinergic synapses throughout the body, causing accumulation of acetylcholine and sustained stimulation of muscarinic, nicotinic, and central nervous system cholinergic receptors. Muscarinic effects (DUMBBBELS mnemonic: Diarrhea, Urination, Miosis, Bradycardia, Bronchospasm/Bronchorrhea, Emesis, Lacrimation, Salivation) result from parasympathetic overstimulation. Nicotinic effects include muscle fasciculations, weakness, and paralysis (including respiratory muscles) from sustained depolarization at the neuromuscular junction. Central effects include anxiety, seizures, and coma. Death typically results from respiratory failure due to the combination of bronchospasm, excessive secretions, and respiratory muscle paralysis. If acetylcholinesterase is not reactivated within 24-48 hours, irreversible 'aging' of the enzyme-inhibitor complex occurs. The nurse performs immediate decontamination (remove clothing, wash skin), administers atropine (to competitively block muscarinic receptors) titrated to drying of secretions, administers pralidoxime (2-PAM, to reactivate acetylcholinesterase before aging occurs), monitors respiratory function closely and prepares for intubation, monitors for intermediate syndrome (delayed-onset weakness 24-96 hours after exposure), uses personal protective equipment to prevent secondary exposure, and monitors serum cholinesterase levels.