Lower Lobe, Higher Suspicion: An Atypical Presentation of Pulmonary Tuberculosis.

Pulmonary tuberculosis (PTB) is a lower respiratory tract infection that most commonly presents as an upper lobe cavitation on imaging. However, atypical lesions, such as lower lung field tuberculosis (LLF-TB), can occur in some individuals, especially with underlying risk factors and comorbidities. We report a case of a 26-year-old male construction worker who presented with multiple episodes of hemoptysis, night sweats, high-grade fevers, and unintentional weight loss. Upon arrival, a complete medical history was taken, which was insignificant except for occupational exposure to silica particles. Initial chest radiographs (CXR) were unremarkable, prompting further evaluation with computed tomography (CT) of the chest, which revealed a necrotizing pneumonia along with ground-glass opacities in the left lower lung field. A rapid antigen detection test (RADT) for  came back negative, and a clinical decision was made to empirically treat for bacterial pneumonia due to the severity of the CT results. Since the clinical suspicion for a tuberculosis (TB) infection was still high, a QuantiFERON-TB Gold test (QIAGEN N.V., Venlo, Netherlands) was ordered, which eventually came back positive. Following this, a bronchoscopy with bronchoalveolar lavage (BAL) was performed, and the presence of acid-fast bacilli (AFB) was confirmed. The patient was discharged home on standard RIPE (rifampin, isoniazid, pyrazinamide, ethambutol) therapy for six months and instructed to follow up with his primary care physician. This case highlights the atypical nature of this patient's presentation regarding the location of their TB infection, as well as the absence of traditional risk factors associated with TB. In this case, we will discuss the diagnostic challenges associated with atypical TB cases and how occupational exposures may contribute to the onset, severity, or location of TB infection.