WBR0678

Author	[[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pharmacology
Sub Category	SubCategory::Pulmonology
Prompt	[[Prompt::An 8-year-old boy recently diagnosed with asthma is brought to the emergency department (ED) for seizures, severe abdominal pain, and vomiting. Upon further questioning, his parents explain that they traveled to USA only one day prior to admission, and the boy has been prescribed an anti-asthma drug by a physician abroad. The boy's vital signs are remarkable for tachycardia and tachypnea. Work-up demonstrates major electrolyte disturbances, including hypokalemia, hypophosphatemia, hypomagnesemia, and hypocalcemia. The ED physician explains to the parents that the patient must have been receiving very high doses of his anti-asthma drug. Which of the following pharmacologic agents is recommended to reverse this patient's condition?]]
Answer A	AnswerA::Esmolol
Answer A Explanation	AnswerAExp::Esmolol is a beta-blocker that is effective for the management of theophylline toxicity.
Answer B	AnswerB::Nicardipine
Answer B Explanation	AnswerBExp::Nicardipine is a calcium channel blocker that is not usually used in cases of theophylline toxicity.
Answer C	AnswerC::Glucagon
Answer C Explanation	AnswerCExp::Glucagon is the antidote for beta-blocker toxicity.
Answer D	AnswerD::Flumazenil
Answer D Explanation	AnswerDExp::Flumazenil is the antidote for benzodiazepine toxicity.
Answer E	AnswerE::Atropine
Answer E Explanation	AnswerEExp::Atropine is the antidote for organophosphate and acetylcholinesterase inhibitor toxicity.
Right Answer	RightAnswer::A
Explanation	[[Explanation::The patient is presenting with signs and symptoms consistent with theophylline toxicity following theophylline overdose. Theophylline induces the release of catecholamines to stimulate the B-adrenergic receptors. It causes systemic symptoms, such as seizures, vomiting, abdominal pain, marked tachycardia, and electrolyte disturbances, such as those observed in the patient. The final outcome in severe overdose is cardiovascular collapse and death. B-blockers are used as antidotes for the management of theophylline toxicity. Esmolol, a beta-1-selective adrenergic receptor antagonist with an ultrashort duration of action and a short half-life (9 min), is has been used in emergency situations as the B-blocker of choice for theophylline toxicity. Other B-blockers that may be administered in theophylline toxicity include either metoprolol or propranolol. Educational Objective: Esmolol, an ultrashort acting beta-1-selective blocker, is recommended to reverse theophylline toxicity. References: Kempf J, Rusterholtz T, Ber C, et al. Haemodynamic study as guideline for the use of beta blockers in acute theophylline poisoning. Intensive Care Med. 1996; 22:585-587.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Esmolol, WBRKeyword::Beta blocker, WBRKeyword::Theophylline overdose, WBRKeyword::Theophylline toxicity, WBRKeyword::Vomiting, WBRKeyword::Abdominal pain, WBRKeyword::Seizure, WBRKeyword::Antidote, WBRKeyword::Reversal agent
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