Snapshot A 60-year-old military officer presents after being attacked with nerve gas. He has increased salivation, lacrimation, and shortness of breath. He also reports involuntary urination and diarrhea. Physical exam reveals wheezing and constricted pupils. His clothes are removed and any remnant nerve gas is washed off his body. Atropine is given. Introduction Clinical definition organophosphate poisoning that results in increased acetylcholine activity Epidemiology demographics farmers or other workers who are exposed to insecticides industrial workers risk factors occupational exposure Etiology insecticides e.g., malathion, parathion, and fenthion nerve gas most rapid and most severe ophthalmic agents e.g., echothiophate and isofluophate herbicide e.g., merphos and tribufos industrial chemicals e.g., tricresyl phosphate Pathogenesis organophosphates irreversibly inhibit acetylcholinesterase and block the metabolism of acetylcholine, resulting in increased acetylcholine activity this causes overstimulation of the muscarinic and nicotinic receptors Prognosis good with treatment, though patients may require intubation before stabilization Presentation Symptoms salivation, sweating, rhinorrhea, and lacrimation involuntary urination or defecation nausea, diarrhea, and vomiting anxiety Physical exam wheezing from bronchospasm miosis and blurred vision bradycardia and hypotension fasciculations seizures DUMBBELSS Diarrhea, Urination, Miosis, Bronchospasm, Bradycardia, Excitation of systems, Lacrimation, Sweating, and Salivation Studies Labs typically not indicated but can be confirmed by measurement of red blood cell cholinesterase levels plasma cholinesterase levels Making the diagnosis most cases are clinically diagnosed Differential Viral gastroenteritis distinguishing factor primarily gastrointestinal upset without other muscarinic and nicotinic effects Treatment Conservative remove clothes and wash the patient indications for all patients for the protection of caregivers and other patients, as organophosphates can be absorbed through the skin Medical atropine indication antidote for all patients as initial therapy competitive inhibitor pralidoxime indication antidote for all patients shortly after atropine is given reactivates acetylcholinesterase benzodiazepines indication for patients with seizures or fasciculations Complications Respiratory failure Seizures
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