Unveiling the Dark Area

A 15-year-old boy presented to the outpatient department with complaints of productive cough, shortness of breath on exertion, and halitosis for 15 days, On probing for the complete history, his parents recollected the history of recurrent respiratory tract infections for the past 3 years. He had a respiratory rate of 15 breaths per minute, and arterial oxygen saturation measured was 99% in the examination room. His physical examination was unremarkable: on auscultation, bilateral polyphonic wheeze was present. Baseline blood investigations done for the patient were found to be normal. Serum total IGE was 1878 and Aspergillus fumigatus specific IGE was 0.38 KUA/L. Chest skiagram and computed tomography images are shown as follows: Figure 1a Chest x-ray (a) hyperlucency of left lower lung field. Hence, a CT thorax was ordered.Figure 1: (a) Shows chest skiagram (b) shows high resolution computed tomography images of the chestFigure 1b Computed tomography shows (b) focal dilatation of the middle portion of the bronchiole with hypodense contents, suggestive of bronchocele associated with hyperinflation of posterobasal segment of the left lower lobe and diffuse centrilobular and panlobular emphysema. The above features prompt the diagnosis of bronchial atresia in the left lower lobe. Congenital bronchial atresia is a rare congenital abnormality.1 The etiology of bronchial atresia is unknown and various hypothesis have been made, the most common being bronchial atresia results due to focal ischemia of a developing bronchus due to vascular injury at 15 weeks of gestation.2 Bronchial atresia is mostly identified as an incidental finding on a chest radiograph. This condition appears on chest radiograph as a hyperinflated or hyperlucent area that may compress adjacent tissue and cause a shift of the mediastinum. The hyperinflation is thought to result from unidirectional flow through collateral airways (pores of Kohn, canals of Lambert). A left-sided predominance occurs for unknown reasons.3 It is more common in male than in female patients (male:female = 16:9).4 This condition often occurs at either the segmental or the subsegmental levels, and rarely occurs at the lobar level.5 Treatment for bronchial atresia is basically conservative, with surgery indicated only if recurrent infection or suspected malignant lesion. Bronchial atresia has been associated with other prenatal lung malformations like congenital cystic adenomatoid malformation, bronchopulmonary sequestration, congenital lobar emphysema. It usually involves the left upper lobe, but here, we have a case with left lower lobe bronchial atresia, hence characteristic thoracic radiology should lead clinicians to suspect bronchial atresia. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.