WBR0058

Author	PageAuthor::William J Gibson
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::General Principles, SubCategory::Infectious Disease
Prompt	[[Prompt::A 39 year old woman presents to your office complaining of fever, muscle soreness, headache and severe malaise one week after returning from a summer vacation on Cape Cod. She shows you a red rash on her leg with a 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 o 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. Lyme disease is caused by the organism Borrelia Burgdorferi, a bacteria which is carried by the Ixodes tick. In its early stages, Lyme disease causes a characteristic “bullseye” rash called erythema chronicum migrans in 80% of patients. Most patients exhibit flu-like symptoms in the early stages of infection. 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 which also uses the Ixodes tick as its vector (among others). Educational Objective: Lyme disease is treated with tetracycline antibiotics (or for later disseminated stage, a third generation cephalosporin such as ceftriaxone). References: First Aid 2012 page 165. IDSA Guidelines: http://cid.oxfordjournals.org/content/43/9/1089.full Tags: #Microbiology #Pharmacology Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::WJG
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