All Sample Questions

Tuberculosis 1

Question

Vignette: A 55-year-old man presents to the clinic with a two-week history of fever, night sweats, and unexplained weight loss. He has a 30 pack-year smoking history, and his past medical history includes chronic obstructive pulmonary disease and a recent hospitalization for pneumonia. On examination, the patient appears fatigued. Auscultation of the lungs reveals crackles in the right lower lobe. Sputum cultures are obtained, which show acid-fast bacilli. Which is the most likely causative organism?

Choices

A. Streptococcus pneumoniae

B. Mycobacterium avium complex

C. Mycobacterium tuberculosis

D. Legionella pneumophila

E. Pseudomonas aeruginosa

Answer

C. Mycobacterium tuberculosis

Explanation

The patient's symptoms of fever, night sweats, weight loss, and lung findings along with the presence of acid-fast bacilli in sputum cultures are suggestive of a Mycobacterium tuberculosis infection, which causes tuberculosis. Tuberculosis is a common opportunistic infection in patients with underlying lung disease, like this patient, especially in those with a history of tobacco use and recent hospitalization. streptococcus pneumoniae (Choice A), legionella pneumophila (Choice D), and Pseudomonas aeruginosa (Choice E) are also causes of pneumonia but do not typically present with systemic symptoms like night sweats and weight loss and are not acid-fast organisms. Mycobacterium avium complex (Choice B) is an atypical mycobacterium and is typically seen in patients with advanced HIV/AIDS, which is not indicated in this patient.