A homeless man presents with fatigue, weight loss, fever, night sweats, and cough. Chest X-ray shows apical pulmonary infiltrates. What is the most likely diagnosis?

• A. Asthma
• B. Chronic bronchitis
• C. Emphysema
• D. Tuberculosis

Answer: (D)

Recognizing tuberculosis comes from combining systemic symptoms with characteristic lung findings in the right risk context. Fatigue, weight loss, fever, and night sweats signal a chronic infectious process that often points to TB rather than a simple bronchitis or asthma flare. The apical pulmonary infiltrates on chest imaging further support reactivation tuberculosis, since upper-lobe involvement is classic due to the higher oxygen tension in those areas, allowing Mycobacterium tuberculosis to thrive and form caseating granulomas. Risk factors like homelessness increase exposure and transmission in crowded settings, making TB more likely in this patient.

In contrast, asthma typically presents with episodic wheeze and reversible airway obstruction rather than systemic constitutional symptoms, and imaging is not characteristically apical. Chronic bronchitis and emphysema are more associated with chronic productive cough or dyspnea and show different radiographic patterns (airways thickening, hyperinflation, or changes related to parenchymal destruction) rather than focal apical infiltrates.