WBR0757: Difference between revisions

Jump to navigation Jump to search
VisualWikitext
No edit summary
m (refreshing WBR questions)
 
(One intermediate revision by one other user not shown)
Line 1: Line 1:
{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}
|QuestionAuthor= {{YD}} (Reviewed by  {{YD}})
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Pharmacology
|MainCategory=Pharmacology
Line 8: Line 8:
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Pulmonology
|SubCategory=Pulmonology
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|MainCategory=Pharmacology
Line 20: Line 21:
|MainCategory=Pharmacology
|MainCategory=Pharmacology
|SubCategory=Pulmonology
|SubCategory=Pulmonology
|Prompt=A 23 year old male patient, previously healthy, presents to the physician's office complaining of difficulty breathing during exercise. The patient denies similar symptoms at rest. The physician suspects exercise-induced asthma and decides to perform a bronchoprovocation challenge test using a crystalline powder. He dilutes the powder in saline containing 0.4% phenol using a sterile technique. For safety purposes also, the physician puts on the table another medication in case of serious side effects occur. Which medication is most likely put nearby on the table during the procedure?
|Prompt=A 23-year-old man with no past medical history presents to the physician's office with complaints of difficulty breathing during exercise. The patient denies similar symptoms at rest. The physician suspects exercise-induced asthma and decides to perform a bronchoprovocation challenge test using a crystalline powder. Using a sterile technique, he dilutes the powder in saline containing 0.4% phenol using a sterile technique. For safety precautions, the physician prepares another drug and puts it on the table to manage any potential serious adverse event that may occur with the bronchoprovocation challenge test. Which drug is most likely put nearby on the table during the procedure?
|Explanation=The patient is undergoing the methacholine challenge test that may help in the diagnosis of asthma. Methacholine is a crystalline powder that is stored at cold temperatures before use. As described in the vignette, it is mixed with saline that contains 0.4% phenol using sterile technique. Methacholine is a synthetic derivative of acetylcholine, but is metabolized much slower by cholinesterase. Its effect can nonetheless be blocked or reduced by atropine or other anticholinergic medications.
|Explanation=The patient is undergoing the methacholine challenge test that helps in the diagnosis of asthma. Methacholine is a crystalline powder that is stored at cold temperatures before use. As described in the vignette, it is mixed with saline containing 0.4% phenol using a sterile technique. Methacholine is a synthetic derivative of acetylcholine that is metabolized much slower than acetylcholine by cholinesterase. Its effect can nonetheless be blocked or reduced by atropine or other anticholinergic agents with bronchodilating action. Serious adverse events are considered rare during methacholine challenge test, but precaution should still be considered regardless of how rare they are. For safety precautions, oxygen and bronchodilators must always be present nearby in the testing area at all times during the procedure. Bronchodilators may be any of epinephrine, atropine, albuterol, or ipratropium. Contraindications to the methacholine challenge test include severe airflow limitations and cardiovascular conditions (such as history of prior myocardial infarction, recent stroke, uncontrolled hypertension, or aortic aneurysm). Other relative contraindications include moderate airflow limitations, pregnancy or nursing, use of cholinesterase inhibitors, and inability to perform acceptable spirometry.
 
For safety purposes, oxygen and medications that decrease the degree of bronchoconstriction induced by methacholine must be present in the testing area nearby at all times. These medications may include any of the following: Epinephrine, atropine, albuterol, ipratropium. However, serious adverse effects are considered rare during methacholine challenge test, but should still be considered regardless of how rare they might be.
 
There are some contraindications to the metacholine challenge test, including severe airflow limitations, cardiovascular conditions, like myocardial infarction or stroke within 3 months, uncontrolled hypertension or aortic aneurysm. Other relative contraindications include: Moderate airflow limitations, pregnancy or nursing mothers, use of cholinesterase inhibitors, and inability to perform acceptable spirometry.
 
Educational Objective:
Atropine, or similar bronchodilators, like epinephrine, B2 agonists, or ipratropium, and oxygen must always be available during methacholine challenge testing for safety purposes in case any serious bronchoconstrictive adverse event occurs.
 
Reference:
Crapo RO, Casaburi R, Coates AL, et al. Guidelines for methacholine and exercise challenge testing - 1999. This official statement of the American Thoracic Society was adopted by the ATS Board of Directors, July 1999. Am J Respir Crit Care Med. 2000; 161(1):309-29.
|AnswerA=Atropine
|AnswerA=Atropine
|AnswerAExp=Atropine is an anti-muscarinic agent that aids in bronchodilation in case severe bronchoconstriction occurs.
|AnswerAExp=[[Atropine]] is a fast-acting, antimuscarinic, bronchodilating agent that may reverse methacholine-induced severe bronchoconstriction.
|AnswerB=Salmetrol
|AnswerB=Salmetrol
|AnswerBExp=Long-acting B2 agonists are generally helpful, but may not be very useful in such acute bronchoconstrictive situations.
|AnswerBExp=Long-acting [[B2 agonist]]s are not very useful in acute bronchoconstrictive situations.
|AnswerC=Edrophonium
|AnswerC=Edrophonium
|AnswerCExp=Edrophonium is an anticholinesterase that may help in the diagnosis of myasthenia gravis.
|AnswerCExp=[[Edrophonium]] is an anticholinesterase that may help in the diagnosis of myasthenia gravis.
|AnswerD=Physostigmine
|AnswerD=Physostigmine
|AnswerDExp=Physostigmine is an anticholinesterase that may cross the blood-brain-barrier. It is a cholinomimetic and may be used to reverse the effects of atropine.
|AnswerDExp=[[Physostigmine]] is an anticholinesterase that crosses the blood-brain-barrier. It is a cholinomimetic and may be used to reverse the effects of atropine.
|AnswerE=Norepinephrine
|AnswerE=Norepinephrine
|AnswerEExp=Norepinephrine is generally not useful in bronchoconstriction because unlike, epinephrine, it lacks B2 activity.
|AnswerEExp=[[Norepinephrine]] is generally not useful in bronchoconstriction because unlike epinephrine, it lacks B2 activity.
|EducationalObjectives=Either atropine or similar fast-acting bronchodilators (epinephrine, B2 agonists, or ipratropium) along with oxygen supplementation must always be available and ready to prevent serious bronchoconstrictive adverse events during methacholine challenge testing.
|References=Crapo RO, Casaburi R, Coates AL, et al. Guidelines for methacholine and exercise challenge testing - 1999. This official statement of the American Thoracic Society was adopted by the ATS Board of Directors, July 1999. Am J Respir Crit Care Med. 2000;161(1):309-29.<br>
First Aid 2014 page 614
|RightAnswer=A
|RightAnswer=A
|WBRKeyword=atropine, methacholine, challenge, test, asthma, exercise, induced, bronchoconstriction, bronchodilation, safety, side, effect, serious, adverse, event
|WBRKeyword=Atropine, Methacholine challenge test, Asthma, Exercise-induced asthma, Shortness of breath, Dyspnea, Oxygen, Safety precautions, Procedure, Bronchodilator, Anticholinergics
|Approved=No
|Approved=Yes
}}
}}

Latest revision as of 01:35, 28 October 2020
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::A 23-year-old man with no past medical history presents to the physician's office with complaints of difficulty breathing during exercise. The patient denies similar symptoms at rest. The physician suspects exercise-induced asthma and decides to perform a bronchoprovocation challenge test using a crystalline powder. Using a sterile technique, he dilutes the powder in saline containing 0.4% phenol using a sterile technique. For safety precautions, the physician prepares another drug and puts it on the table to manage any potential serious adverse event that may occur with the bronchoprovocation challenge test. Which drug is most likely put nearby on the table during the procedure?]]
Answer A AnswerA::Atropine
Answer A Explanation [[AnswerAExp::Atropine is a fast-acting, antimuscarinic, bronchodilating agent that may reverse methacholine-induced severe bronchoconstriction.]]
Answer B AnswerB::Salmetrol
Answer B Explanation [[AnswerBExp::Long-acting B2 agonists are not very useful in acute bronchoconstrictive situations.]]
Answer C AnswerC::Edrophonium
Answer C Explanation [[AnswerCExp::Edrophonium is an anticholinesterase that may help in the diagnosis of myasthenia gravis.]]
Answer D AnswerD::Physostigmine
Answer D Explanation [[AnswerDExp::Physostigmine is an anticholinesterase that crosses the blood-brain-barrier. It is a cholinomimetic and may be used to reverse the effects of atropine.]]
Answer E AnswerE::Norepinephrine
Answer E Explanation [[AnswerEExp::Norepinephrine is generally not useful in bronchoconstriction because unlike epinephrine, it lacks B2 activity.]]
Right Answer RightAnswer::A
Explanation [[Explanation::The patient is undergoing the methacholine challenge test that helps in the diagnosis of asthma. Methacholine is a crystalline powder that is stored at cold temperatures before use. As described in the vignette, it is mixed with saline containing 0.4% phenol using a sterile technique. Methacholine is a synthetic derivative of acetylcholine that is metabolized much slower than acetylcholine by cholinesterase. Its effect can nonetheless be blocked or reduced by atropine or other anticholinergic agents with bronchodilating action. Serious adverse events are considered rare during methacholine challenge test, but precaution should still be considered regardless of how rare they are. For safety precautions, oxygen and bronchodilators must always be present nearby in the testing area at all times during the procedure. Bronchodilators may be any of epinephrine, atropine, albuterol, or ipratropium. Contraindications to the methacholine challenge test include severe airflow limitations and cardiovascular conditions (such as history of prior myocardial infarction, recent stroke, uncontrolled hypertension, or aortic aneurysm). Other relative contraindications include moderate airflow limitations, pregnancy or nursing, use of cholinesterase inhibitors, and inability to perform acceptable spirometry.

Educational Objective: Either atropine or similar fast-acting bronchodilators (epinephrine, B2 agonists, or ipratropium) along with oxygen supplementation must always be available and ready to prevent serious bronchoconstrictive adverse events during methacholine challenge testing.
References: Crapo RO, Casaburi R, Coates AL, et al. Guidelines for methacholine and exercise challenge testing - 1999. This official statement of the American Thoracic Society was adopted by the ATS Board of Directors, July 1999. Am J Respir Crit Care Med. 2000;161(1):309-29.
First Aid 2014 page 614]]

Approved Approved::Yes
Keyword WBRKeyword::Atropine, WBRKeyword::Methacholine challenge test, WBRKeyword::Asthma, WBRKeyword::Exercise-induced asthma, WBRKeyword::Shortness of breath, WBRKeyword::Dyspnea, WBRKeyword::Oxygen, WBRKeyword::Safety precautions, WBRKeyword::Procedure, WBRKeyword::Bronchodilator, WBRKeyword::Anticholinergics
Linked Question Linked::
Order in Linked Questions LinkedOrder::
Retrieved from "https://www.wikidoc.org/index.php?title=WBR0757&oldid=1671994"