WBR0058: Difference between revisions

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|QuestionAuthor=William J Gibson
|QuestionAuthor=William J Gibson
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|SubCategory=General Principles, Infectious Disease
|SubCategory=Dermatology, General Principles, Infectious Disease
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|SubCategory=General Principles, Infectious Disease
|SubCategory=Dermatology, General Principles, Infectious Disease
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|SubCategory=General Principles, Infectious Disease
|SubCategory=Dermatology, General Principles, Infectious Disease
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|SubCategory=General Principles, Infectious Disease
|SubCategory=Dermatology, General Principles, Infectious Disease
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|SubCategory=General Principles, Infectious Disease
|SubCategory=Dermatology, General Principles, Infectious Disease
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|SubCategory=General Principles, Infectious Disease
|SubCategory=Dermatology, General Principles, Infectious Disease
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|SubCategory=General Principles, Infectious Disease
|SubCategory=Dermatology, General Principles, Infectious Disease
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|MainCategory=Microbiology
|MainCategory=Microbiology, Pharmacology
|SubCategory=General Principles, Infectious Disease
|SubCategory=Dermatology, General Principles, Infectious Disease
|Prompt=A 39-year-old woman presents to her primary care physician complaining of fever, muscle soreness, headache and severe malaise one week after returning from a summer vacation on Cape Cod.  Physical exam is significant for a red rash on her leg with an inner ring clearing resembling a bullseye.  What is the optimal treatment for this patient?
|Prompt=A 39-year-old woman presents to her primary care physician complaining of fever, muscle soreness, headache and severe malaise one week after returning from a summer vacation on Cape Cod.  Physical exam is significant for a red rash on her leg with an inner ring clearing resembling a bullseye.  What is the optimal treatment for this patient?
|Explanation=The patient in this vignette has the early stages of Lyme disease caused by the spirochete Borrelia burgdorferi.  Borrelia Burgdorferi is a zoonotic bacteria that is carried by the Ixodes tick.  In its early stages, Lyme disease causes flu-like symptoms and a characteristic “bullseye” rash called erythema chronicum migrans in 80% of patients.    Tetracyline antibiotics such as doxycycline are used for Lyme disease and have the advantage that they are effective against human granulocytic anaplasmosis, an infectious disease caused by Anaplasma phagocytophilum that also uses the Ixodes tick as its vector (among others).  For later disseminated stages of Lyme disease, a third generation cephalosporin such as ceftriaxone is indicated.
|Explanation=The patient in this vignette has the early stages of Lyme disease caused by the spirochete Borrelia burgdorferi.  Borrelia Burgdorferi is a zoonotic bacteria that is carried by the Ixodes tick.  In its early stages, Lyme disease causes flu-like symptoms and a characteristic “bullseye” rash called erythema chronicum migrans in 80% of patients.    Tetracyline antibiotics such as doxycycline are used for Lyme disease and have the advantage that they are effective against human granulocytic anaplasmosis, an infectious disease caused by Anaplasma phagocytophilum that also uses the Ixodes tick as its vector (among others).  For later disseminated stages of Lyme disease, a third generation cephalosporin such as ceftriaxone is indicated.

Revision as of 01:42, 24 February 2014

 
Author PageAuthor::William J Gibson
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Microbiology, MainCategory::Pharmacology
Sub Category SubCategory::Dermatology, SubCategory::General Principles, SubCategory::Infectious Disease
Prompt [[Prompt::A 39-year-old woman presents to her primary care physician complaining of fever, muscle soreness, headache and severe malaise one week after returning from a summer vacation on Cape Cod. Physical exam is significant for a red rash on her leg with an inner ring clearing resembling a bullseye. What is the optimal treatment for this patient?]]
Answer A AnswerA::Erythromycin
Answer A Explanation AnswerAExp::'''Incorrect:''' Erythromycin is a macrolide used to treat atypical pneumonias
Answer B AnswerB::Doxycycline
Answer B Explanation AnswerBExp::'''Correct:''' Doxyclince is a tetracycline used to treat Lyme disease.
Answer C AnswerC::Penicillin
Answer C Explanation AnswerCExp::'''Incorrect:''' Penicillin is a beta-lactam antibiotic used to treat gram-positive organisms and syphillis.
Answer D AnswerD::Trimethoprim-Sulfamethoxazole
Answer D Explanation AnswerDExp::'''Incorrect:''' Trimethoprim-Sulfamethoxazole (Bactrim) inhibits dihyrofolate reductase and is used to treat UTIs
Answer E AnswerE::Ciprofloxacin
Answer E Explanation AnswerEExp::'''Incorrect:''' Ciprofloxacin is a fluoroquinolone which inhibits DNA gyrase and is used to treat gram-negative rods
Right Answer RightAnswer::B
Explanation [[Explanation::The patient in this vignette has the early stages of Lyme disease caused by the spirochete Borrelia burgdorferi. Borrelia Burgdorferi is a zoonotic bacteria that is carried by the Ixodes tick. In its early stages, Lyme disease causes flu-like symptoms and a characteristic “bullseye” rash called erythema chronicum migrans in 80% of patients. Tetracyline antibiotics such as doxycycline are used for Lyme disease and have the advantage that they are effective against human granulocytic anaplasmosis, an infectious disease caused by Anaplasma phagocytophilum that also uses the Ixodes tick as its vector (among others). For later disseminated stages of Lyme disease, a third generation cephalosporin such as ceftriaxone is indicated.

Educational Objective: Early lyme disease is best treated with tetracycline antibiotics.

References:

First Aid 2014 page 141

IDSA Guidelines: http://cid.oxfordjournals.org/content/43/9/1089.full

Note: Linked to WBR0057 and WBR0059
Educational Objective:
References: ]]

Approved Approved::Yes
Keyword WBRKeyword::Microbiology, WBRKeyword::Zoonotic, WBRKeyword::Animal, WBRKeyword::Tick, WBRKeyword::Lyme disease, WBRKeyword::Lyme, WBRKeyword::Bacteria, WBRKeyword::Rash, WBRKeyword::Dermatology, WBRKeyword::Pharmacology, WBRKeyword::Drugs, WBRKeyword::Antibiotics, WBRKeyword::Linked
Linked Question Linked::
Order in Linked Questions LinkedOrder::