WBR0152

Author	PageAuthor::William J Gibson
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Musculoskeletal/Rheumatology, SubCategory::General Principles, SubCategory::Infectious Disease
Prompt	[[Prompt::A 54-year-old homeless male presents to the Emergency room with back pain, fever, night sweats and anorexia. He reports that these symptoms have lasted approximately two weeks. The patient denies intravenous drug use, but reports heavy alcohol abuse and is sexually active. CT scan reveals a hilar opacity in the lung and lytic destruction of the anterior portion of the T6 vertebral body. Intravenous antibiotics are administered. Which of the following is the most likely causal organism?]]
Answer A	AnswerA::Pseudomonas aeruginosa
Answer A Explanation	[[AnswerAExp::Psuedomonas aeruginosa may cause osteomyelitis and should be suspected in an intravenous drug user. However, the hilar opacity implicates tuberculosis infection more strongly. The presentation of this patient is more consistent with Pott's disease.]]
Answer B	AnswerB::Salmonella typhi
Answer B Explanation	[[AnswerBExp::Salmonella is a common cause of osteomyelitis in indiviuals with sickle cell anemia.]]
Answer C	AnswerC::Mycobacterium tuberculosis
Answer C Explanation	AnswerCExp::Pott's disease is a presentation of extrapulmonary tuberculosis that involves the spinal vertebrae. The hilar and spinal lesions in this patient strongly suggest tuberculosis infection.
Answer D	AnswerD::Staphylococcus aureus
Answer D Explanation	[[AnswerDExp::While Staphylococcus aureus is the most common cause of osteomyelitis overall, it is not responsible for Pott’s disease.]]
Answer E	AnswerE::Neisseria gonorrhea
Answer E Explanation	AnswerEExp::''N. gonnorrhea'' uncommonly causes osteomyelitis. When it does, it is a subacute illness with minimal systemic symptoms
Right Answer	RightAnswer::C
Explanation	[[Explanation::The patient in this vignette is suffering from Pott’s disease, a vertebral infection of the spine caused by extrapulmonary Mycobacterium tuberculosis. Homelessness is a risk factor for TB and the lung lesion should raise your suspicion for any other complications of TB. The patient has positive radiographic findings for a caseating spinal lesion, consistent with tuberculosis infection. The treatment for Pott's disease is the standard treatment for other tuberculosis infection: RIPE: Rifampin, Isoniazid, Pyrazinamade, and Ethambutol. Educational Objective: Suspect tuberculosis infection in a homeless patient with a lung lesion and spinal disease. References: First Aid 2014 page 134 Blumberg HM, Burman WJ, Chaisson RE, et al. American Thoracic Society/Centers for Disease Control and Prevention/Infectious Diseases Society of America: treatment of tuberculosis. Am J Respir Crit Care Med. Feb 15 2003;167(4):603-62.]]
Approved	Approved::Yes
Keyword	WBRKeyword::Tuberculosis, WBRKeyword::Mycobacterium tuberculosis, WBRKeyword::Microbiology, WBRKeyword::Bacteria
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