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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor=[[User:Gonzalo Romero|Gonzalo A. Romero, M.D.]] [mailto:gromero@wikidoc.org]
|QuestionAuthor=[[User:Gonzalo Romero|Gonzalo A. Romero, M.D.]] [mailto:gromero@wikidoc.org] {{Alison}}
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Embryology, Microbiology, Pharmacology
|MainCategory=Embryology, Microbiology, Pharmacology
Line 20: Line 20:
|MainCategory=Embryology, Microbiology, Pharmacology
|MainCategory=Embryology, Microbiology, Pharmacology
|SubCategory=Infectious Disease
|SubCategory=Infectious Disease
|Prompt=A 2-year-old girl is brought to the pediatrician because her mother is concerned about her teeth being darker than usual, even though she has been brushing her daughter’s kid consistently. She states that at week 8 of pregnancy, she developed a ring-like rash in the leg after a camping trip, for which she took leftover antibiotic from her brother when he developed a similar rash after a boy-scout excursion into rural Connecticut. Which of the following mechanisms of action corresponds to the most likely drug used?
|Prompt=A 2-year-old girl is brought to the pediatrician because her mother is concerned about her teeth appear abnormally dark. She states that her daughter developed a ring-like rash on her leg after a nature walk, which appeared to be similar to a rash that her 17-year-old son developed following a camping trip. The mother administered her daughter the leftover antibiotics that had been prescribed to her teenage son for his rash. Which of the following mechanisms of action corresponds to the antibiotic most likely provided to the young girl?
|Explanation=The clinical vignette describes a patient who delivered a child who currently has discolored teeth.  She took an antibiotic during pregnancy to treat Lyme’s disease.  The treatment of choice of [[Lyme]] disease is [[tetracycline]], which is contraindicated in pregnancy due to bone and teeth malformation.  Tetracycline, specifically doxycycline inhibits the protein synthesis by binding to the 30s ribosomal subunit and preventing the aminoacyl-tRNA attachment.
|Explanation=The clinical vignette describes a patient who delivered a child who currently has discolored teeth.  She took an antibiotic during pregnancy to treat Lyme’s disease.  The treatment of choice of [[Lyme]] disease is [[tetracycline]], which is contraindicated in pregnancy due to bone and teeth malformation.  Tetracycline, specifically doxycycline inhibits the protein synthesis by binding to the 30s ribosomal subunit and preventing the aminoacyl-tRNA attachment.
[[File:BullseyeLymeDiseaseRash.jpg|center|400px]]
[[File:BullseyeLymeDiseaseRash.jpg|center|400px]]
<font color="MediumBlue"><font size="4">'''Educational Objective:''' </font></font> tetracycline use during pregnancy is associated with teeth discoloration (teratogenic)
|EducationalObjectives= When tetracycline is administered to young children, it is often associated with teeth discoloration (teratogenic)
<br>
 
'''References:''' First Aid 2013 Microbiology-Pharmacology chapter.
|References= First Aid 2013 Microbiology-Pharmacology chapter.
|AnswerA=Prevents attachment of aminoacyl-tRNA
|AnswerA=Prevents attachment of aminoacyl-tRNA
|AnswerAExp=<font color="Green">'''Correct.'''</font> See overall explanation
|AnswerAExp=See overall explanation
|AnswerB=Inhibits the formation of initiation complex
|AnswerB=Inhibits the formation of initiation complex
|AnswerBExp=<font color="red">'''Incorrect.'''</font> This is the mechanism of action of [[aminoglycosides]] used for gram negative rod infections
|AnswerBExp=This is the mechanism of action of [[aminoglycosides]] used for gram negative rod infections.
|AnswerC=Blocks translocation
|AnswerC=Blocks translocation
|AnswerCExp=<font color="red">'''Incorrect.'''</font> This is the mechanism of action of [[macrolides]], used to treat atypical pneumonias (Mycoplasma, Chlamydia, Legionella), URiI, STDs, gram-positive cocci (streptococcal infections in patients allergic to penicillin), and Neisseria
|AnswerCExp=This is the mechanism of action of [[macrolides]], used to treat atypical pneumonias (Mycoplasma, Chlamydia, Legionella), URiI, STDs, gram-positive cocci (streptococcal infections in patients allergic to penicillin), and Neisseria.
|AnswerD=Require 02 for uptake;
|AnswerD=Require 02 for uptake;
|AnswerDExp=<font color="red">'''Incorrect.'''</font> This refers to [[aminoglycosides]]
|AnswerDExp=This often corresponds with [[aminoglycosides]] use.
|AnswerE=Inhibit peptidyl-transferase action
|AnswerE=Inhibit peptidyl-transferase action
|AnswerEExp=<font color="red">'''Incorrect.'''</font> This is the mechanism of action of [[chloramphenicol]]
|AnswerEExp=This is the mechanism of action associated with [[chloramphenicol]].
|RightAnswer=A
|RightAnswer=A
|WBRKeyword=Teratogen
|WBRKeyword=Teratogen
|Approved=Yes
|Approved=Yes
}}
}}

Revision as of 13:29, 7 July 2014
Author [[PageAuthor::Gonzalo A. Romero, M.D. [1] (Reviewed by Alison Leibowitz)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Embryology, MainCategory::Microbiology, MainCategory::Pharmacology
Sub Category SubCategory::Infectious Disease
Prompt [[Prompt::A 2-year-old girl is brought to the pediatrician because her mother is concerned about her teeth appear abnormally dark. She states that her daughter developed a ring-like rash on her leg after a nature walk, which appeared to be similar to a rash that her 17-year-old son developed following a camping trip. The mother administered her daughter the leftover antibiotics that had been prescribed to her teenage son for his rash. Which of the following mechanisms of action corresponds to the antibiotic most likely provided to the young girl?]]
Answer A AnswerA::Prevents attachment of aminoacyl-tRNA
Answer A Explanation AnswerAExp::See overall explanation
Answer B AnswerB::Inhibits the formation of initiation complex
Answer B Explanation [[AnswerBExp::This is the mechanism of action of aminoglycosides used for gram negative rod infections.]]
Answer C AnswerC::Blocks translocation
Answer C Explanation [[AnswerCExp::This is the mechanism of action of macrolides, used to treat atypical pneumonias (Mycoplasma, Chlamydia, Legionella), URiI, STDs, gram-positive cocci (streptococcal infections in patients allergic to penicillin), and Neisseria.]]
Answer D AnswerD::Require 02 for uptake;
Answer D Explanation [[AnswerDExp::This often corresponds with aminoglycosides use.]]
Answer E AnswerE::Inhibit peptidyl-transferase action
Answer E Explanation [[AnswerEExp::This is the mechanism of action associated with chloramphenicol.]]
Right Answer RightAnswer::A
Explanation [[Explanation::The clinical vignette describes a patient who delivered a child who currently has discolored teeth. She took an antibiotic during pregnancy to treat Lyme’s disease. The treatment of choice of Lyme disease is tetracycline, which is contraindicated in pregnancy due to bone and teeth malformation. Tetracycline, specifically doxycycline inhibits the protein synthesis by binding to the 30s ribosomal subunit and preventing the aminoacyl-tRNA attachment.

Educational Objective: When tetracycline is administered to young children, it is often associated with teeth discoloration (teratogenic)
References: First Aid 2013 Microbiology-Pharmacology chapter.]]

Approved Approved::Yes
Keyword WBRKeyword::Teratogen
Linked Question Linked::
Order in Linked Questions LinkedOrder::
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