Pathophysiology
Clinical meaning
Organophosphates are irreversible acetylcholinesterase inhibitors found in pesticides, nerve agents, and some medications. By inhibiting acetylcholinesterase, they prevent breakdown of acetylcholine at synapses, causing excessive cholinergic stimulation at muscarinic receptors (parasympathetic effects), nicotinic receptors (neuromuscular junction and sympathetic ganglia), and central nervous system. The SLUDGEM mnemonic describes muscarinic effects: Salivation, Lacrimation, Urination, Defecation, GI cramping, Emesis, and Miosis. Nicotinic effects include muscle fasciculations, weakness, paralysis, tachycardia, and hypertension. Death typically results from respiratory failure due to bronchospasm, excessive secretions, and diaphragmatic paralysis. The antidote is atropine (blocks muscarinic effects) combined with pralidoxime (reactivates acetylcholinesterase if given before aging occurs, typically within 24-48 hours).