WBR0778

Author	[[PageAuthor::Serge Korjian M.D. (Reviewed by Serge Korjian)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Dermatology, SubCategory::Infectious Disease
Prompt	[[Prompt::A 33-year-old-man presents to the emergency department for sudden onset right-sided facial paralysis. He reports that he woke up today and noticed he had lost all control of the right-side of his face and looked like he had just suffered a stroke. The patient denies any similar previous episodes. He explains that that he does not smoke or drink and lives a very healthy lifestyle. Physical exam is notable for right-sided facial paralysis involving most of the forehead. CT scan of the brain is unremarkable. During your examination, the patient remembers that a few weeks ago he noticed a rash on his left flank that looked much like a bull’s eye that self-resolved and was wondering if this was related to his current problem. What would you expect to find on pathology had the rash been biopsied?]]
Answer A	AnswerA::Septal and lobar panniculitis with septal fibrosis
Answer A Explanation	AnswerAExp::These findings are characteristic of erythema nodosum.
Answer B	AnswerB::Yeast pseudohyphae in the stratum corneum
Answer B Explanation	AnswerBExp::Typically seen in biopsies of tinea versicolor skin lesions
Answer C	AnswerC::Eosinophils and mast cells with giant cell reaction
Answer C Explanation	AnswerCExp::This is seen in allergic reactions to foreign bodies.
Answer D	AnswerD::Inflammation with spirochetes on silver stain
Answer D Explanation	AnswerDExp::Typically seen in biopsies of erythema migrans in the context of lyme disease.
Answer E	AnswerE::Hyperkeratosis and acanthosis
Answer E Explanation	AnswerEExp::Usually seen in biopsies of acanthosis nigricans.
Right Answer	RightAnswer::D
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. In the initial phase of lyme disease, a characteristic rash known as erythema migrans evolves that expands forming a bull's eye pattern with central clearing. This usually occurs between 2-20 days after the initial tick bite and inoculation. The rash is not an inflammatory or an allergic reaction; it is the result of direct spirochetal infection of the skin and pathology examination reveals inflammation with spirochetes on silver stain. Treatment of lyme disease is with doxycyline or ceftriaxone. Educational Objective: Erythema migrans is charactersitic of early stage lyme disease and is secondary to active spirochetal infection of the skin. References: Biesiada G, Czepiel J, Leśniak MR, Garlicki A, Mach T. Lyme disease: review. Arch Med Sci. 2012;8(6):978-82.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Lyme disease, WBRKeyword::Erythema migrans, WBRKeyword::Biopsy, WBRKeyword::Borrelia burgdorferi
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