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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}, {{AJL}} {{Alison}}
|QuestionAuthor={{Rim}}
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Pharmacology
|MainCategory=Pharmacology
Line 20: Line 20:
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Neurology
|SubCategory=Neurology
|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 to facilitate access to the surgical site by paralyzing his abdominal muscles. Several minutes after the injection is administered, the patient's heart rate and blood pressure increase to 135 bpm and 182/99 mmHg. The monitor shows an increase in minute ventilation and carbon dioxide production. His core temperature also begins to increase steadily reaching 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.
|Explanation=Malignant hyperthermia is a condition that describes a severe reaction usually occuring 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.


|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.


|EducationalObjectives= Dantrolene is the treatment of choice in malignant hyperthermia.


 
Reference:<br>
|References= Hopkins PM. Malignant hyperthermia: advances in clinical management and diagnosis. Br J Anaesth. 2000;85(1):118-28.
Hopkins PM. Malignant hyperthermia: advances in clinical management and diagnosis. Br J Anaesth. 2000;85(1):118-28.
|AnswerA=Succinylcholine
|AnswerA=Succinylcholine
|AnswerAExp=Succinylcholine is a muscle relaxant that can cause malignant hyperthermia. It has no role in the treatment of malignant hyperthermia.
|AnswerAExp=Succinylcholine is a muscle relaxant that can cause malignant hyperthermia. It has no role in the treatment of malignant hyperthermia.

Revision as of 16:13, 17 September 2014

 
Author [[PageAuthor::Rim Halaby, M.D. [1]]]
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 to facilitate access to the surgical site by paralyzing his abdominal muscles. Several minutes after the injection is administered, the patient's heart rate and blood pressure increase to 135 bpm and 182/99 mmHg. The monitor shows an increase in minute ventilation and carbon dioxide production. His core temperature also begins to increase steadily reaching 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.]]
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 that describes a severe reaction usually occuring 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.


Reference:
Hopkins PM. Malignant hyperthermia: advances in clinical management and diagnosis. Br J Anaesth. 2000;85(1):118-28.
Educational Objective:
References: ]]

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