WBR0777

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology, MainCategory::Pathophysiology
Sub Category	SubCategory::Infectious Disease
Prompt	[[Prompt::A 23 year old man presents to the clinic for an unusual looking rash that he first noticed today. He reports that although the rash feels slightly warmer than the surrounding skin, it is neither itchy nor painful. He does not report any recent lesion or bite to the area, but reports that he was recently on vacation on the northeastern coast where he went hiking for a few days. Otherwise, the patient denies any fatigue, chills, fever, headaches, myalgia or joint pain. On physical exam you notice the lesion shown below. What would you expect the patient to develop six months later if left untreated for his current condition? ]]
Answer A	AnswerA::Bell’s palsy
Answer A Explanation	AnswerAExp::Bell's palsy usually occurs several weeks after the initial tick bite.
Answer B	AnswerB::Third degree heart block
Answer B Explanation	AnswerBExp::AV nodal blocks also occurs several weeks after the initial tick bite.
Answer C	AnswerC::Recurrence of the same rash
Answer C Explanation	AnswerCExp::The same erythema migrans rash can occur within a few weeks after the initial tick bite.
Answer D	AnswerD::Meningitis
Answer D Explanation	AnswerDExp::Meningitis also occurs several weeks after the initial tick bite.
Answer E	AnswerE::Arthritis with severe joint swelling
Answer E Explanation	AnswerEExp::Chronic monoarthritis and migratory polyarthritis is a typical manifestation of late Lyme disease occurring several months to years after the initial tick bite.
Right Answer	RightAnswer::E
Explanation	[[Explanation::Lyme disease is a systemic animal-borne illness caused by the spirochete Borrelia burgdorferi transmitted by the Ixodes tick. The disease typically affects the skin, nervous system, musculoskeletal system and heart. The disease is mostly seen in the northeastern United States. Classically it has 3 phases. The inital phase involves a typical rash known as erythema migrans that expands forming a bull's eye pattern with central clearing. The first stage occurs between 2-20 days after the initial tick bite and inoculation. The second stage is characterized by neurologic manifestations including meningitis, AV nodal block, and Bell's palsy usuallu occuring several weeks after the inital bite. The final phase, occuring several months to years after the inital exposure, is characterized by chronic monoarthritis and migratory polyarthritis with associated cutaneous manifestations. Treatment is usually with ceftriaxone or doxycyline. Learning Objective: Several months after the initial inoculation of Borrelia burgdorferi, the most common clinical manifestation of Lyme disease is chronic monoarthritis and migratory polyarthritis. Reference: Biesiada G, Czepiel J, Leśniak MR, Garlicki A, Mach T. Lyme disease: review. Arch Med Sci. 2012;8(6):978-82. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::Lyme disease, WBRKeyword::Borrelia burgdorferi, WBRKeyword::Erythema migrans, WBRKeyword::Migratory polyarthritis
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Order in Linked Questions	LinkedOrder::