Congenital lobar overinflation (CLO) (previosuly called congenital lobar emphysema) is a congenital lung abnormality that results in progressive overinflation of one or more lobes of a neonate lung. Various mechanisms have been postulated including an obstructive check valve mechanism at the bronchial level 2.
Congenital lobar overinflation is more common in males (M:F = 3:1) 5.
Patients typically present with respiratory distress, most commonly in the neonatal period, and usually within the first 6 months of life 5.
In congenital lobar overinflation, a lobe (or more) become distended and may or may not have more alveoli. There are many presumed mechanisms for progressive overdistension of a lobe including obstruction, cartilage deficiency, dysplasia, and immaturity. Most cases are idiopathic.
CLO may be associated with congenital heart defects such as:
Interestingly there is quite a pronounced predilection for some lobes:
- left upper lobe: most common, 40-45%
- right middle lobe: 30%
- right upper lobe: 20%
- may involve more than a single lobe in 5%
- much rarer in the lower lobes.
Therefore despite the left upper lobe being most commonly affected, the right hemithorax is the most common side to be affected 6.
Plain film: chest radiograph
Immediate postpartum period
The affected lobe tends to appear opaque and homogeneous because of fetal lung fluid or it may show a diffuse reticular pattern that represents distended lymphatic channels filled with fetal lung fluid.
- appears as an area of hyperlucency in the lung with a paucity of vessels
- mass effect with mediastinal shift and hemidiaphragmatic depression
- decubitus films lying on the affected side will show little or no change in lung volume
- lateral film may demonstrate posterior displacement of the heart
- shows above features in greater detail
- attenuation of vascular structures in affected lobe 4
- may also show compressive atelectasis of neighbouring lobes
Mildly symptomatic patients are usually followed up. A lobectomy can be considered in severe cases 3.
General imaging differential considerations include:
- congenital cystic adenomatoid malformation (CCAM)/congenital pulmonary airway malformation (CPAM)
- pulmonary arterial hypoplasia
- pulmonary hypoplasia
- bronchial atresia: the distal to the atretic segment can have air trapping
- differential for unilateral transradiant hemithorax
- 1. Blickman JG, Parker BR, Barnes PD. Pediatric radiology, the requisites. Mosby Inc. (2009) ISBN:0323031250. Read it at Google Books - Find it at Amazon
- 2. Berrocal T, Madrid C, Novo S et-al. Congenital anomalies of the tracheobronchial tree, lung, and mediastinum: embryology, radiology, and pathology. Radiographics. 24 (1): e17. doi:10.1148/rg.e17 - Pubmed citation
- 3. Man DW, Hamdy MH, Hendry GM et-al. Congenital lobar emphysema: problems in diagnosis and management. Arch. Dis. Child. 1983;58 (9): 709-12. doi:10.1136/adc.58.9.709 - Free text at pubmed - Pubmed citation
- 4. Daltro P, Fricke BL, Kuroki I et-al. CT of congenital lung lesions in pediatric patients. AJR Am J Roentgenol. 2004;183 (5): 1497-506. AJR Am J Roentgenol (full text) - Pubmed citation
- 5. Donoghue VB, Bjørnstad PG. Radiological Imaging of the Neonatal Chest. Springer Verlag. (2007) ISBN:3540337482. Read it at Google Books - Find it at Amazon
- 6. Stigers KB, Woodring JH, Kanga JF. The clinical and imaging spectrum of findings in patients with congenital lobar emphysema. Pediatr. Pulmonol. 1992;14 (3): 160-70. - Pubmed citation
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Congenital lobar emphysema (CLE)||✗|
|Congenital lobar overinflation (CLO)||✗|
|Congenital lobar emphysema||✓|