WBR0494: Difference between revisions

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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}
|QuestionAuthor={{Rim}}, {{AJL}} {{Alison}}
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Immunology
|MainCategory=Immunology
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|MainCategory=Immunology
|MainCategory=Immunology
|SubCategory=Endocrine
|SubCategory=Endocrine
|Prompt=A 27-year-old newly graduate nurse applied for a job at a hospital.  As part of her pre-employment screening tests, she had to submit a copy of her vaccination history as well as to undergo a ppd test to screen for tuberculosis. The patient received an intradermal injection of ppd and was asked to come back again after 48 hours to reevaluate the site of injection. Which of the following mechanisms would be involved if the patient returned with an induration at the site of the ppd injection?
|Prompt=A 27-year-old newly graduated nurse applying for a job at a hospital has to submit a copy of her vaccination history and undergo a PPD test, to screen for tuberculosis. She receives an intradermal injection of PPD and is asked to return 48 hours later, so that site of injection can be reevaluated. Which of the following mechanisms is involved if the female returns with an induration at the site of the PPD injection?
|Explanation=[[PPD test]], also known as the Mantoux test, tuberculin sensitivity test, Pirquet test, is a screening tool [[for tuberculosis]].  The results of this test must be interpreted carefully. The person's medical risk factors determine at which increment (5 mm, 10 mm, or 15 mm) of induration the result is considered positive.  [[PPD]] test is characterized by delayed T-cell mediated immune reactions and hence it is a type IV hypersensitivity immune reaction.
|Explanation=[[PPD test]], also known as the Mantoux test, tuberculin sensitivity test, and Pirquet test, is a screening tool [[for tuberculosis]].  The individual's medical risk factors determine the increment (5 mm, 10 mm, or 15 mm) of induration at which the result is considered positive.  A [[PPD]] test, a type IV hypersensitivity immune reaction, is characterized by delayed T-cell mediated immune reactions.


Educational Objective:
|EducationalObjectives= Hypersensitivity type IV disorders include conditions characterized by delayed T-cell mediated immune reactions, such as [[contact dermatitis]] and [[PPD]] testing.
Hypersensitivity type IV disorders include conditions characterized by delayed T-cell mediated immune reactions such as [[contact dermatitis]], [[PPD]] testing.
|AnswerA=Hypersensitivity type I
|AnswerA=Hypersensitivity type I
|AnswerAExp=Type I hypersensitivity disorders include [[anaphylaxis]], [[atopy]] and [[allergy]].  PPD skin test is not a type I hypersensitivity disorder.
|AnswerAExp=Type I hypersensitivity disorders include [[anaphylaxis]], [[atopy]], and [[allergy]].  A PPD skin test is not a type I hypersensitivity immune reaction.
|AnswerB=Hypersensitivity type II
|AnswerB=Hypersensitivity type II
|AnswerBExp=Type II hypersensitivity disorders include conditions where an antibody is directed against a specific antigen.  PPD skin test involves a delayed T cell mediated response that is consistent with type IV hypersensitivity.
|AnswerBExp=Type II hypersensitivity disorders include conditions where an antibody is directed against a specific antigen.  A PPD skin test involves a delayed T cell mediated response that is consistent with type IV hypersensitivity.
|AnswerC=Hypersensitivity type III
|AnswerC=Hypersensitivity type III
|AnswerCExp=Hypersensitivity type III disorders include conditions where an antigen-antibody complex forms and activates the complement system.  PPD skin test is not a type III hypersensitivity order.
|AnswerCExp=Hypersensitivity type III disorders include conditions where an antigen-antibody complex forms and activates the complement system.  A PPD skin test is not a type III hypersensitivity immune reaction.
|AnswerD=Hypersensitivity type IV
|AnswerD=Hypersensitivity type IV
|AnswerDExp=Hypersensitivity type IV disorders include conditions characterized by delayed T-cell mediated immune reactions such as [[contact dermatitis]], [[tuberculosis]] testing.
|AnswerDExp=Hypersensitivity type IV disorders include conditions characterized by delayed T-cell mediated immune reactions, such as [[contact dermatitis]] and [[tuberculosis]] testing.
|AnswerE=Not a hypersensitivity disorder
|AnswerE=Not a hypersensitivity disorder
|AnswerEExp=PPD skin test is a type IV hypersensitivity disorder.
|AnswerEExp=PPD skin test is a type IV hypersensitivity disorder.
|RightAnswer=B
|RightAnswer=D
|WBRKeyword=Hypersensitivity, PPD test
|WBRKeyword=Hypersensitivity, PPD test, immune system, testing, TB, tuberculosis, screening,
|Approved=No
|Approved=Yes
}}
}}

Revision as of 19:16, 29 July 2014
Author [[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Immunology
Sub Category SubCategory::Endocrine
Prompt [[Prompt::A 27-year-old newly graduated nurse applying for a job at a hospital has to submit a copy of her vaccination history and undergo a PPD test, to screen for tuberculosis. She receives an intradermal injection of PPD and is asked to return 48 hours later, so that site of injection can be reevaluated. Which of the following mechanisms is involved if the female returns with an induration at the site of the PPD injection?]]
Answer A AnswerA::Hypersensitivity type I
Answer A Explanation [[AnswerAExp::Type I hypersensitivity disorders include anaphylaxis, atopy, and allergy. A PPD skin test is not a type I hypersensitivity immune reaction.]]
Answer B AnswerB::Hypersensitivity type II
Answer B Explanation AnswerBExp::Type II hypersensitivity disorders include conditions where an antibody is directed against a specific antigen. A PPD skin test involves a delayed T cell mediated response that is consistent with type IV hypersensitivity.
Answer C AnswerC::Hypersensitivity type III
Answer C Explanation AnswerCExp::Hypersensitivity type III disorders include conditions where an antigen-antibody complex forms and activates the complement system. A PPD skin test is not a type III hypersensitivity immune reaction.
Answer D AnswerD::Hypersensitivity type IV
Answer D Explanation [[AnswerDExp::Hypersensitivity type IV disorders include conditions characterized by delayed T-cell mediated immune reactions, such as contact dermatitis and tuberculosis testing.]]
Answer E AnswerE::Not a hypersensitivity disorder
Answer E Explanation AnswerEExp::PPD skin test is a type IV hypersensitivity disorder.
Right Answer RightAnswer::D
Explanation [[Explanation::PPD test, also known as the Mantoux test, tuberculin sensitivity test, and Pirquet test, is a screening tool for tuberculosis. The individual's medical risk factors determine the increment (5 mm, 10 mm, or 15 mm) of induration at which the result is considered positive. A PPD test, a type IV hypersensitivity immune reaction, is characterized by delayed T-cell mediated immune reactions.

Educational Objective: Hypersensitivity type IV disorders include conditions characterized by delayed T-cell mediated immune reactions, such as contact dermatitis and PPD testing.
References: ]]

Approved Approved::Yes
Keyword WBRKeyword::Hypersensitivity, WBRKeyword::PPD test, WBRKeyword::immune system, WBRKeyword::testing, WBRKeyword::TB, WBRKeyword::tuberculosis, WBRKeyword::screening
Linked Question Linked::
Order in Linked Questions LinkedOrder::
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