WBR1500

Author	[[PageAuthor::William J Gibson (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::General Principles, SubCategory::Infectious Disease
Prompt	[[Prompt::A 35-year-old man presents to his primary care physician for muscular pain, sweating, and fever over the past five days. He reports that his fever tends to worsen throughout the day and breaks at night. The patient denies any recent travel to foreign countries or new sexual partners. He works as a goat farmer and hunts deer on the weekends. Physical exam is remarkable for cervical lymphadenopathy and a body odor that resembles wet hay. If left untreated, development of which of the following complications is most likely?]]
Answer A	AnswerA::Meningitis
Answer A Explanation	AnswerAExp::The waxing/waning fever in this patient is suggestive of ''Brucella'' infection. Meningitis has been reported as a very rare complication of brucellosis, but it is not considered a common feature of infection.
Answer B	AnswerB::Orchitis
Answer B Explanation	[[AnswerBExp::Orchitis is not associated with Brucella infection. It can be caused by mumps virus or STIs, such as Chlamydia and Gonorrhea.]]
Answer C	AnswerC::Myocarditis
Answer C Explanation	[[AnswerCExp::Myocarditis is a common complication of Lyme disease, another zoonotic infection.]]
Answer D	AnswerD::Endocarditis
Answer D Explanation	[[AnswerDExp::Brucella infection is not commonly associated with endocarditis. Infection with other zoonotic organisms, such as Bartonella spp. can give rise to endocarditis. However, the most common cause of infective, native-valve endocarditis is Streptococcus viridans. More recent data suggest that Staphylococcus aureus may be accounting for an increasing share as well.]]
Answer E	AnswerE::Osteomyelitis
Answer E Explanation	[[AnswerEExp::Bone and joint complications are the most common focal complication of Brucella infection. The majority of cases of Brucella osteomyelitis affect the axial skeleton, with vertebral osteomyelitis occurring in approximately 40% of these cases.]]
Right Answer	RightAnswer::E
Explanation	[[Explanation::The patient in this vignette has a classic case of undulating fever, caused by infection with Brucella species. Brucellosis is a highly contagious zoonotic infection that is most commonly associated with ingestion of either unpasteurized dairy products or undercooked meat. Exposure to products from goats is especially associated with brucellosis. The classic triad of brucellosis includes undulating fever, sweating with a characteristic wet hay odor, and migratory arthralgia/myalgia. Bone and joint complications are the most common focal complication of Brucella infection. The majority of cases of Brucella osteomyelitis affect the axial skeleton, with vertebral osteomyelitis occurring in approximately 40% of these cases. Educational Objective: Undulating fever is caused by infection with Brucella species. Bone and joint complications are the most common focal complication of Brucella infection. References: Colmenero JD, Ruiz-mesa JD, Plata A, et al. Clinical findings, therapeutic approach, and outcome of brucellar vertebral osteomyelitis. Clin Infect Dis. 2008;46(3):426-33. First Aid 2015 page 142.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Microbiology, WBRKeyword::Zoonotic, WBRKeyword::Bacteria, WBRKeyword::Undulating fever, WBRKeyword::Wet hay odor, WBRKeyword::Brucella, WBRKeyword::Gram negative, WBRKeyword::Infection, WBRKeyword::Brucellosis, WBRKeyword::Osteomyelitis, WBRKeyword::Complications
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