WBR0933

Author	PageAuthor::William J Gibson (Reviewed by Serge Korjian)
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pharmacology
Sub Category	SubCategory::Renal, SubCategory::General Principles
Prompt	[[Prompt::A 6-year-old boy is brought to the emergency department by his parents after he began vomiting and exhibiting signs of intoxication. The patient reports that the symptoms started after he drank a blue liquid he found in the garage. The patient's labs reveal a creatinine of 3.6 mg/dL, a serum sodium of 140 mEq/L, a serum bicarbonate of 14 mEq/L, and a chloride of 98 mEq/L. Urinalysis reveals hematuria. Which of the following should be promptly administered to this patient?]]
Answer A	AnswerA::Fomepizole
Answer A Explanation	AnswerAExp::Fomepizole is a potent inhibitor of alcohol dehydrogenase; similar to ethanol, it acts to block the formation of the toxic metabolites. It is primarily used as an antidote to ethylene glycol poisoining.
Answer B	AnswerB::Flumazenil
Answer B Explanation	AnswerBExp::Flumazenil is a benzodiazepine receptor antagonist used to treat benzodiazepine overdose.
Answer C	AnswerC::Disulfiram
Answer C Explanation	[[AnswerCExp::Disulfiram is an inhibitor of acetaldehyde dehydrogenase, an enzyme that metabolizes acetaldehyde to acetate. The accumulation of acetaldehyde caused by concurrent disulfiram and ethanol ingestion causes unpleasant side effects. For this reason, disulfiram is used to help alcoholics stop drinking.]]
Answer D	AnswerD::Glucagon
Answer D Explanation	AnswerDExp::Glucagon can be used to treat beta-blocker overdose.
Answer E	AnswerE::Ammonium Chloride
Answer E Explanation	AnswerEExp::Ammonium chloride can be given for methamphetamine overdose. It helps to acidify the urine and increase renal clearance of the drug.
Right Answer	RightAnswer::A
Explanation	[[Explanation::Children are the most frequent victims of ethylene glycol poisoning. Ethylene glycol can be found in items such as antifreeze, and has a sweet taste which can cause children to drink it. Ethylene glycol itself is not toxic, but its metabolites are. Ethylene glycol is first metabolized to glycolaldehyde, which then undergoes further oxidation to glycolate, glyoxylate, and oxalate. It is glycolate and oxalate that are primarily responsible for the metabolic acidosis and renal damage that accompany ethylene glycol poisoning. The antidotes to ethylene glycol poisoning are ethanol and fomepizole, both of which inhibit the metabolism of ethylene glycol. Ethanol competitively inhibits the metabolism of ethylene glycol by alcohol dehydrogenase. Fomepizole is also a competitive inhibitor of alcohol dehydrogenase. Hemodialysis should be initiated in any patient with known ethylene glycol or methanol poisoning. Educational Objective: Fomepizole acts as an antidote to ethylene glycol poisoning by competitive inhibition of alcohol dehydrogenase. References: Leth PM, Gregersen M. Ethylene glycol poisoning. Forensic Sci Int. 2005;155(2-3):179-84.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Poisoning, WBRKeyword::Ethylene glycol, WBRKeyword::Alcohol, WBRKeyword::Antidote, WBRKeyword::Toxin, WBRKeyword::EtOH, WBRKeyword::Emergency, WBRKeyword::Poison
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