Children with congenital emphysema usually present with respiratory distress
as neonates. It usually affects one or two lobes. The left upper lobe,
the right middle lobe, and the right upper lobe are most often involved
[1]. In as many as 50% of the cases, the cause remains unknown [1,2]. In
these cases the cause is probably collapse of the bronchus because of segmental
bronchial cartilage underdevelopment, which also causes ball valve obstruction
and air trapping [3]. Other causes of bronchial obstruction include congenital
bronchial stenosis, intraluminal mucous plugs, tracheal cysts, obstructing
mediastinal cysts, vascular compression, bronchopulmonary dysplasia and
tumors [4].
Radiographically the affected lobe is hyperdistended and hyperlucent with
widely dispersed vasculature. It usually shifts the mediastinum to
the contralateral side [3]. If emphysema is profound, herniation of the
emphysematous lung across the anterosuperior mediastinum occurs [4]. A
chest film immediately after birth may show a radiopaque lobe because of
retained fetal lung fluid [5]. Chest films later may show a hyperdistended
and hyperlucent lung, which may displace other structures. CT scans
show a hypodense enlarged lobe with widely dispersed vasculature [5].
.
Figure 1. Congenital lobar emphysema of the right upper and
right middle lobes. Note hyperdistended and hyperlucent right
lung, shift of the mediastinum to the left, herniation of the
emphysematous lung to the left, and atelectasis of the left lobe.
..
.
Figure 2. A CT scan of the same patient shows a hyperlucent right
upper lobe with increased space between interstitial septae, herniation
of the right upper lobe to the left hemithorax, and a collapsed left
lung.
REFERENCES
1. Leonidas JC, Berdon W. The neonatal chest. In: Silverman FN, Kuhn
JP, editors. Caffey's pediatric x-ray diagnosis: an integrated imaging
approach. 9th ed. Mosby: St. Louis, 1993:2006-7.
2. Hedlund GL, Griscom NT, Cleveland RH, Kirks DR. Respiratory system.
In: Kirks DR, Griscom NT, editors. Practical pediatric imaging: diagnostic
radiology of infants and children. 3rd ed. Philadelphia: Lippincott-Raven,
1998:667-71.
3. Mandell GA. Imaging evaluation of the neonate. In: Goodman LR, Putman
CE, editors. Critical care imaging. 3rd ed. Philadelphia: W.B. Saunders,
1992:443-4.
4. Swischuk LE. Respiratory system. In: Imaging of the newborn, infant,
and young child. 4th ed. Baltimore: Williams & Wilkins, 1997;91-5.
5. Donnelly LF, Frush DP. Localized radiolucent chest lesions in neonates:
causes and differentiation. AJR 1999;172:1651-8.