WBR0678

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pharmacology
Sub Category	SubCategory::Pulmonology
Prompt	[[Prompt::An 8 year old boy, with a past medical history of 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 before admission, and a new asthma medication has been very recently prescribed by a physician abroad. His vital signs are remarkable for tachycardia and tachypnea. Work-up shows major electrolyte disturbances, including hypokalemia, hypophosphatemia, hypomagnesemia, and hypocalcemia. The ED physician explains to the parents that the patient must have been taking very high doses of his asthma medication. Which of the following medications should be prescribed to reverse the patient's condition?]]
Answer A	AnswerA::Esmolol
Answer A Explanation	AnswerAExp::Esmolol is a beta-blocker that is effective for theophylline toxicity.
Answer B	AnswerB::Nicardipine
Answer B Explanation	AnswerBExp::Nicardipine is a calcium channel blocker that is not usually used as antidote.
Answer C	AnswerC::Glucagon
Answer C Explanation	AnswerCExp::Glucagon may be used as antidote for beta-blocker toxicity.
Answer D	AnswerD::Flumazenil
Answer D Explanation	AnswerDExp::Flumazenil may be used as antidote for benzodiazepine toxicity.
Answer E	AnswerE::Atropine
Answer E Explanation	AnswerEExp::Atropine may be used as 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 due to overdose in his theophylline, which is used to treat his asthma. 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 in the vignette. The final outcome in severe overdose is cardiovascular collapse and death. B-blockers are used as antidotes for management of theophylline toxicity. Esmolol, a beta-1-selective adrenergic receptor antagonist with a short duration of action, is has been used in emergency situations as a choice of B-blockers. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::esmolol, WBRKeyword::beta, WBRKeyword::blocker, WBRKeyword::blockers, WBRKeyword::theophylline, WBRKeyword::overdose, WBRKeyword::toxicity, WBRKeyword::vomiting, WBRKeyword::abdominal, WBRKeyword::pain, WBRKeyword::seizure, WBRKeyword::adrenergic, WBRKeyword::receptor, WBRKeyword::antagonist, WBRKeyword::antagonism
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::