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 an ultrashort duration of action and a short half-life (9 min), is has been used in emergency situations as a choice of B-blockers. Other B-blockers that may be used are metoprolol and propranolol.
Educational Objective: Esmolol, an ultrashort acting beta-1-selective blocker, is used to reverse theophylline toxicity. Reference:
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::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:: |