Congenital > Bronchatresia

Bronchial Atresia:

View cases of bronchial atresia

Clinical:

Congenital bronchial atresia is a rare and typically isolated anomaly. The lesion is probable the result of an in-utero vascular insult after the 15th week of gestation that results in focal obliteration of the bronchial lumen. The lesion most commonly affects the bronchus to the apical posterior segment of the left upper lobe, followed by the segmental bronchi of the right upper and middle lobes [6]. Involvement of the lower lobe bronchi is extremely rare. Distal to the atretic segment the involved bronchus usually contains impacted mucus. The involved pulmonary segment typically becomes hyperaerated as a result of collateral air flow via the interalveolar pores of Kohn and the bronchoalveolar channels of Lambert [5]. Affected patients are usually asymptomatic and the abnormality is typically detected when a chest radiograph is performed for some other reason (average age of diagnosis is 17 years [6]). Males are affected more than females (2:1) [6]. Treatment is observation. Surgery is reserved for patients experiencing complications such as recurrent infection (about 20% of patients), or interference with normal growth or function of adjacent lung.

Bronchial agenesis results in unilateral agenesis of the lung and occurs with equal frequency on either side.

X-ray:

On prenatal US, the fluid-filled lung just distal to the atresia will be seen as an echogenic area that is indistinguihable from other lung masses [7]. On fetal MR, it appears as a focal lung mass with homogeneously high signal on T2 images [7].

Classically on CXR there is a central tubular or branching density that subtends an area of hyperlucency (due to over-distention of the involved lobe). The mucous plug may appear as a hilar or extrahilar mass. The presence of the mucus plug is essential in order to aid in differentiation from congenital lobar emphysema. Findings on CT are similar- with a characteristic tubular or branching mucoid imapaction of the bronchus distal to the atresia surrounded by an area of emphysematous lung. Occasionally, the bronchi can contain a fluid level or be completely air filled [4].

In patients with bronchial agenesis there is shift of mediastinal structures into the affected hemithorax. Chest cage asymmetry may not be evident in the neonatal/ infant period. 

REFERENCES:

(1) Resp Med 1994; Rossoff LJ, Steinberg H. Bronchial atresia and mucocele: a report of two cases. 88(10), 789-791 (No abstract available)

(2) AJR 1980; Cohen AM, et al. Computed tomography in bronchial atresia. 135(5), 1097-1099 (No abstract available)

(3) AJR 1983; 141:909-914

(4) Radiographics 2002; Zylak CF. Developmental lung anomalies in the adult: radiologic-pathologic correlation. 22: S25-S43

(5) Radiology 2008; Lee EY, et al. Multidetector CT evaluation of congenital lung abnormalities. 247: 632-648

(6) Radiographics 2008; Martinez S, et al. Mucoid impactions: finger-in-glove sign and other CT and radiographics features. 28: 1369-1382

(7) Radiographics 2010; Biyyam DR, et al. Congenital lung abnormalities: embryologic features, prenatal diagnosis, and post natal radiologic-pathologic correlation. 30: 1721-1738

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