A 44‐year‐old Vietnamese man with HIV presented with a cavitary pneumonitis after 1 week of subjective fever, nonproductive cough, 3‐ to 4‐pound weight loss, and 2 days of azithromycin therapy from his primary care provider. He denied shortness of breath or dyspnea. His medical history included a diagnosis of tuberculosis 20 years ago in Vietnam treated using a 2‐drug regimen for 1½ years. Six months prior to his presentation he had returned to Vietnam for a visit. Other than a resting tachycardia, his exam revealed an occasional crackle in both lungs. A CBC showed a WBC of 10,100 with a normal differential. The rest of his labs were normal. The 2‐view chest x‐ray demonstrated a diffuse heterogeneous consolidation in the right lung and the lateral aspects of the upper, mid and lower left lung fields. A 3.4‐cm thick‐walled cavity was identified in the anterior segment of the right upper lobe. He was started on IV hydration and admitted to airborne isolation for a high suspicion of active tuberculosis. However, empiric anti‐infective treatment was not initiated. A CT scan of the chest confirmed the right upper lobe thick walled cavity and identified a smaller 1.3‐cm thin‐walled cavity in the right lower lobe. A PPD was negative and 3 poor‐quality sputum specimens were negative on acid fast staining. By the fifth hospital day, he had started to become dyspneic and short of breath. A biopsy of the larger cavity was performed via interventional radiology. On hospital day 7, his O2 saturation dropped to 74% on room air and high‐flow oxygen was started. A repeat chest x‐ray was unchanged and a CT angiogram of the chest was negative for pulmonary embolus. Bactrim and prednisone were initiated with dramatic improvement by day 9. On day 10 the biopsy results came back with the silver stain positive for pneumocystis.
Pneumocystis jiroveci pneumonia in HIV patients uncommonly cavitates, but when present, the cavitary process may mimic other more common cavitary entities such as tuberculosis. Understanding the lobar and segmental lung anatomy and cavitary disease predilection can assist in determining causation.
This case illustrates the importance of lung cavity location. Tubercular cavities preferentially arise in the apical and posterior segments of the upper lobe and the superior segment of the lower lobe. Finding a cavity in the anterior segment of the upper lobe dramatically reduces the likelihood of tuberculosis, and should prompt clinicians to suspect other etiologies.
To cite this abstract:Collins N, Seethala S. Upper Lobe Lung Cavities — Is Tb Always First in the Differential?. Abstract published at Hospital Medicine 2013, May 16-19, National Harbor, Md. Abstract 438. Journal of Hospital Medicine. 2013; 8 (suppl 2). https://www.shmabstracts.com/abstract/upper-lobe-lung-cavities-is-tb-always-first-in-the-differential/. Accessed March 31, 2020.