WBR0393: Difference between revisions

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|Prompt=During a major abdominal surgery, a patient receives an injection of pancuronium, which paralyzes his abdominal muscles in order to facilitate access to the surgical site. Several minutes after the injection is administered, the patients experiences an increase in  minute ventilation, carbon dioxide production, heart rate to 135 bpm, blood pressure to 182/99 mmHg, and core temperature to 41.2 °C. Troubled by the unstable vitals, the anesthesiologist administers a second intravenous agent to counteract the effects of the muscle relaxant. The patient's vitals stabilize soon after the second injection and he begins to defervesce. Which of the following intravenous agents did the anesthesiologist most likely administer to the patient?
|Prompt=During a major abdominal surgery, a patient receives an injection of pancuronium, which paralyzes his abdominal muscles in order to facilitate access to the surgical site. Several minutes after the injection is administered, the patients experiences an increase in  minute ventilation, carbon dioxide production, heart rate to 135 bpm, blood pressure to 182/99 mmHg, and core temperature to 41.2 °C. Troubled by the unstable vitals, the anesthesiologist administers a second intravenous agent to counteract the effects of the muscle relaxant. The patient's vitals stabilize soon after the second injection and he begins to defervesce. Which of the following intravenous agents did the anesthesiologist most likely administer to the patient?


|Explanation=[[Malignant hyperthermia]], a condition characterized by a severe reaction frequently occurring under [[general anesthesia]], manifests with the exposure to certain anesthetic drugs and muscle relaxants in patients with prior susceptibility. There are no clinical features specific to [[malignant hyperthermia]], but early signs typically include tachycardia and tachypnea, progressing to hyperthermia, generalized muscle rigidity, oliguria, and arrhythmia. Without rapid intervention, [[malignant hyperthermia]] can lead to death. [[Dantrolene]], frequently used in treatment of [[malignant hyperthermia]], depresses excitation-contraction coupling in skeletal muscles by binding to the ryanodine receptor, and decreasing free intracellular calcium concentration.
|Explanation=[[Malignant hyperthermia]] is a condition characterized by a severe reaction, frequently occurring under general anaesthesia. It is a manifestation to the exposure to certain anesthetic drugs and muscle relaxants in patients with prior susceptibility to develop this condition. There are no clinical features specific for malignant hyperthermia. Typically, early signs include tachycardia and tachypnea, that progress to hyperthermia, generalized muscle rigidity, oliguria, arrhythmia and eventual death if treatment is not initiated. Recognition of early signs are important to warrant rapid intervention. Dantrolene is the medication of choice for the treatment of malignant hyperthermia. Dantrolene depresses excitation-contraction coupling in skeletal muscle by binding to the ryanodine receptor, and decreasing free intracellular calcium concentration.
 
 
|EducationalObjectives= Dantrolene is the treatment of choice in malignant hyperthermia.




|EducationalObjectives= [[Dantrolene]] is the treatment of choice for [[malignant hyperthermia]]. It acts by inhibiting excitation-contraction coupling in skeletal muscle by binding to the ryanodine receptor. Without intervention, [[malignant hyperthermia]] is often fatal.
|References= Hopkins PM. Malignant hyperthermia: advances in clinical management and diagnosis. Br J Anaesth. 2000;85(1):118-28.
|References= Hopkins PM. Malignant hyperthermia: advances in clinical management and diagnosis. Br J Anaesth. 2000;85(1):118-28.
|AnswerA=Succinylcholine
|AnswerA=Succinylcholine
|AnswerAExp=[[Succinylcholine]], a muscle relaxant, can result in [[malignant hyperthermia]].
|AnswerAExp=Succinylcholine is a muscle relaxant that can cause malignant hyperthermia. It has no role in the treatment of malignant hyperthermia.
|AnswerB=Dantrolene
|AnswerB=Dantrolene
|AnswerBExp=[[Dantrolene]] is the treatment of choice for [[malignant hyperthermia]]. It acts by inhibiting excitation-contraction coupling in skeletal muscle by binding to the ryanodine receptor.
|AnswerBExp=Dantrolene is the treatment of choice for malignant hyperthermia. It acts by inhibiting excitation-contraction coupling in skeletal muscle by binding to the ryanodine receptor.
|AnswerC=Etomidate
|AnswerC=Etomidate
|AnswerCExp=[[Etomidate]], an anesthetic agent, can cause [[malignant hyperthermia]].
|AnswerCExp=Etomidate is anesthetic agent that can cause malignant hyperthermia. It has no role in the treatment of malignant hyperthermia.
|AnswerD=Physostigmine
|AnswerD=Physostigmine
|AnswerDExp=[[Physostigmine]], a reversible cholinesterase inhibitor, has no role in the treatment of [[malignant hyperthermia]].
|AnswerDExp=Physostigmine is a reversible cholinesterase inhibitor. It has no role in the treatment of malignant hyperthermia.
|AnswerE=Pralidoxime
|AnswerE=Pralidoxime
|AnswerEExp=Pralidoxime, a sympathomimetic drug used in the treatment of organophosphate poisoning, has no role in the treatment of [[malignant hyperthermia]].
|AnswerEExp=Pralidoxime is a sympathomimetic drug used in the treatment of organophosphate poisoning. It has no role in the treatment of malignant hyperthermia.
|RightAnswer=B
|RightAnswer=B
|WBRKeyword=Dantrolene, Pancuronium, Malignant hyperthermia, anesthesia, adverse reaction, muscle relaxent, anestthetic agent
|WBRKeyword=Dantrolene, Pancuronium, Malignant hyperthermia,
|Approved=Yes
|Approved=No
}}
}}

Revision as of 16:13, 17 September 2014
Author [[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Pharmacology
Sub Category SubCategory::Neurology
Prompt [[Prompt::During a major abdominal surgery, a patient receives an injection of pancuronium, which paralyzes his abdominal muscles in order to facilitate access to the surgical site. Several minutes after the injection is administered, the patients experiences an increase in minute ventilation, carbon dioxide production, heart rate to 135 bpm, blood pressure to 182/99 mmHg, and core temperature to 41.2 °C. Troubled by the unstable vitals, the anesthesiologist administers a second intravenous agent to counteract the effects of the muscle relaxant. The patient's vitals stabilize soon after the second injection and he begins to defervesce. Which of the following intravenous agents did the anesthesiologist most likely administer to the patient?]]
Answer A AnswerA::Succinylcholine
Answer A Explanation AnswerAExp::Succinylcholine is a muscle relaxant that can cause malignant hyperthermia. It has no role in the treatment of malignant hyperthermia.
Answer B AnswerB::Dantrolene
Answer B Explanation AnswerBExp::Dantrolene is the treatment of choice for malignant hyperthermia. It acts by inhibiting excitation-contraction coupling in skeletal muscle by binding to the ryanodine receptor.
Answer C AnswerC::Etomidate
Answer C Explanation AnswerCExp::Etomidate is anesthetic agent that can cause malignant hyperthermia. It has no role in the treatment of malignant hyperthermia.
Answer D AnswerD::Physostigmine
Answer D Explanation AnswerDExp::Physostigmine is a reversible cholinesterase inhibitor. It has no role in the treatment of malignant hyperthermia.
Answer E AnswerE::Pralidoxime
Answer E Explanation AnswerEExp::Pralidoxime is a sympathomimetic drug used in the treatment of organophosphate poisoning. It has no role in the treatment of malignant hyperthermia.
Right Answer RightAnswer::B
Explanation [[Explanation::Malignant hyperthermia is a condition characterized by a severe reaction, frequently occurring under general anaesthesia. It is a manifestation to the exposure to certain anesthetic drugs and muscle relaxants in patients with prior susceptibility to develop this condition. There are no clinical features specific for malignant hyperthermia. Typically, early signs include tachycardia and tachypnea, that progress to hyperthermia, generalized muscle rigidity, oliguria, arrhythmia and eventual death if treatment is not initiated. Recognition of early signs are important to warrant rapid intervention. Dantrolene is the medication of choice for the treatment of malignant hyperthermia. Dantrolene depresses excitation-contraction coupling in skeletal muscle by binding to the ryanodine receptor, and decreasing free intracellular calcium concentration.

Educational Objective: Dantrolene is the treatment of choice in malignant hyperthermia.
References: Hopkins PM. Malignant hyperthermia: advances in clinical management and diagnosis. Br J Anaesth. 2000;85(1):118-28.]]

Approved Approved::No
Keyword WBRKeyword::Dantrolene, WBRKeyword::Pancuronium, WBRKeyword::Malignant hyperthermia
Linked Question Linked::
Order in Linked Questions LinkedOrder::
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