Question | Discussion | References | CME Credit

Updated December 9, 2005

Case 5: A 32-Year-Old with Chronic Cough and Suspected Tuberculosis

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A 32-year-old man presents with fatigue and occasional chest pain. He notes an intermittent cough productive of scanty, yellowish phlegm for the past 4 weeks and has lost approximately 10 pounds. He immigrated from Vietnam 3 years ago and has no regular source of medical care. A chest radiograph reveals a patchy right upper lobe infiltrate (Figure 1). A diagnosis of tuberculosis (TB) is suspected. Further work-up shows a tuberculin skin test with 6 mm of induration, and three sputum smears negative for acid-fast bacilli (AFB). The patient agrees to HIV testing and is found to be HIV-infected.

Which one of the following statements is most likely TRUE?

A If a nucleic acid amplification test on sputum is positive for Mycobacterium tuberculosis, sputum culture is not required.
B If the pleural effusion is tapped, there is greater than 80% likelihood that a Ziehl-Neelsen stain of pleural fluid will show AFB.
C The patient’s small tuberculin skin test reaction is probably due to prior BCG vaccination, and an alternative diagnosis should be sought.
D Therapy for TB should be initiated while the diagnostic work-up continues.
E The patient’s CD4 cell count is almost certainly less than 100 cells/mm3.

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    Figure 1. Chest Radiograph

    This chest radiograph shows a patchy right upper lobe infiltrate with no evidence of cavitation.

    Figure 1