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 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 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
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