Basilar Predominant Emphysema: Thinking beyond Alpha-1-Antitrypsin Deficiency

Abstract

Basilar predominant emphysema, or disproportionate emphysematous involvement of the lung bases compared to the apices, is an uncommon radiographic pattern of emphysema traditionally associated with alpha-1-antitrypsin deficiency (AATD). We present a case of a 59-year-old female with 41 pack-year tobacco use, Stage IV COPD with supplemental oxygen, and bibasilar predominant emphysema who successfully underwent bronchoscopic lung volume reduction. She presented with recurrent hospitalizations for frequent exacerbations. After lung reduction, the patient displayed improvement in functional status without hospitalizations at the 15-month follow-up. Careful history taking is essential for any patients diagnosed with lower lobe emphysema to elucidate the underlying etiology. This case challenges the notion that basilar emphysema is sensitive or specific for AATD and emphasizes that this pattern of emphysema has a broad differential diagnosis and alternative etiologies should be considered. Our patient was ultimately diagnosed with smoking-related emphysema, with atypical bibasilar involvement. Furthermore, basilar predominant emphysema should be considered a separate entity from its apical predominant counterpart.

Figure 1

Chest X-rays of posterioanterior and lateral view showing bilateral lung hyperinflation, diaphragm flattening, and hyperlucency.

Figure 2

CT chest of upper and lower lobes showing panlobular emphysema with predominantly lower lobe involvement.

Figure 3

CT chest 3D reconstruction showing decreased lung field on bilaterally lower lobes and the left upper lobe.