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Organophosphate and nerve agent poisoning results from exposure to compounds that irreversibly inhibit acetylcholinesterase, leading to excessive accumulation of acetylcholine at synapses. These toxins are found in pesticides, chemical warfare agents, and some medications, causing a characteristic cholinergic crisis with muscarinic, nicotinic, and central nervous system effects.
Organophosphates and nerve agents bind covalently to acetylcholinesterase, preventing the breakdown of acetylcholine at neuromuscular junctions, autonomic ganglia, and parasympathetic nerve terminals. This leads to continuous stimulation of cholinergic receptors, causing muscarinic effects (miosis, salivation, lacrimation, urination, defecation), nicotinic effects (muscle fasciculations, paralysis), and central nervous system dysfunction including seizures and respiratory depression.
Diagnosis relies on recognizing the classic cholinergic toxidrome: pinpoint pupils, excessive secretions, muscle fasciculations, and altered mental status, often with a history of pesticide or chemical exposure. Treatment involves immediate decontamination, supportive care with airway management, and specific antidotes including atropine to counteract muscarinic effects and pralidoxime to reactivate acetylcholinesterase if given early. Benzodiazepines are used for seizure control and neuroprotection.