WBR0152

Author	[[PageAuthor::William J Gibson (Reviewed by Yazan Daaboul, M.D.)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Musculoskeletal/Rheumatology
Prompt	[[Prompt::A 54-year-old homeless man presents to the emergency department with back pain, fever, and dry cough. He reports that these symptoms have approximately been present for the past 2 months. The patient was evaluated for similar symptoms 1 month earlier but a definite diagnosis was not made at the time. He reports he has been smoking 1 pack of cigarettes daily for the past 30 years and drinks 7-8 beers each day. The patient denies intravenous drug use. Upon review of systems, the patient complains of a 6-month history of anorexia, weight loss, and night sweats. Work-up in the ED is remarkable for a hilar opacity in the lung and presence of a mass with lytic destruction of the anterior portion of the T6-T9 vertebral bodies on imaging. CT-guided fine needle aspiration (FNA) of the vertebral mass confirms the diagnosis. Which of the following organisms is most likely responsible for this patient's symptoms?]]
Answer A	AnswerA::''Pseudomonas aeruginosa''
Answer A Explanation	[[AnswerAExp::Psuedomonas aeruginosa may cause osteomyelitis and should be suspected among intravenous drug users. 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 among 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'' does not commonly causes osteomyelitis. When it does, it is a subacute illness with minimal systemic symptoms.
Right Answer	RightAnswer::C
Explanation	[[Explanation::Pott’s disease (spinal tuberculosis) is an infection of the spinal vertebrae caused by extrapulmonary Mycobacterium tuberculosis. Approximately 20-30% of patients with tuberculosis (TB) have extrapulmonary involvement. Pott's disease accounts for approximately 50% of skeletal tuberculosis. Pott's disease is a difficult diagnosis that is often missed upon initial presentation, especially when patients do not present with any signs of symptoms that suggest pulmonary tuberculosis. The anterior spine is often affected in Pott's disease, resulting in kyphotic deformity. Pott's disease may be complicated by neurological involvement or spinal epidural abscess. Homelessness is a risk factor for TB and the lung lesion should raise the suspicion for any other complications of TB. The patient has positive radiographic findings for a 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. If antibiotics fail, surgical intervention may be required, especially among patients with complicated disease and severe symptoms. Educational Objective: Suspect tuberculosis infection in a homeless patient with a lung lesion and spinal disease (Pott's disease). References: 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. 2003;167(4):603-62. First Aid 2014 page 134]]
Approved	Approved::Yes
Keyword	WBRKeyword::Tuberculosis, WBRKeyword::Mycobacterium tuberculosis, WBRKeyword::Microbiology, WBRKeyword::Bacteria, WBRKeyword::Pott's disease, WBRKeyword::Extrapulmonary, WBRKeyword::TB, WBRKeyword::Spinal TB, WBRKeyword::Back pain
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::