Introduction
Histopathology of congenital lobar emphysema with marked overdistention of all alveoli.
Resected lobe is overexpanded and shows no other intrinsic abnormality.
Background
Congenital lobar emphysema (CLE) is a potentially reversible though possibly life-threatening cause of respiratory distress in the neonate.
Lobar emphysema can occur in hypoalveolar (fewer than expected number of alveoli) and polyalveolar (more than expected number of alveoli) forms.
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Presentation
Demographics
Congenital lobar emphysema (CLE) is most often detected in neonates or identified during in utero ultrasound; however, less severely affected patients may present in infancy or childhood.
Anomalies are infrequent and usually present at birth. Lobar distention can be visible during in utero ultrasound as an overinflated, fluid-filled lobe; in less severe cases, the diagnosis is made in infancy or childhood.
Extreme lobar overdistention is life-threatening.
- Emergency lobectomy may be required if the lobe cannot be decompressed by selective intubation of the opposite side or by placing the infant in the decubitus position with the involved lobe dependent.1
- In severely affected patients, the lung is overinflated and will immediately herniate through the surgical incision.2
- Less severely affected patients are managed conservatively with gentle ventilation and monitoring to ensure that respiratory status does not worsen.
Presentation and natural history
Congenital lobar emphysema (CLE) presents with overexpansion of a pulmonary lobe and resultant compression of the remaining ipsilateral lung. A mediastinal shift away from the increased-volume lung can also compress the contralateral lung. The abnormality is related to intrinsic bronchial narrowing. In these cases, there is weakened or absent bronchial cartilage, so that there is inspiratory air entry but collapse of the narrow bronchial lumen during expiration. This bronchial defect results in lobar air trapping. In the case of congenital extrinsic compression, such as by a large pulmonary artery, affected cartilage rings are malformed, soft, and collapsible in response to the long-term in utero extrinsic effect.
A single lobe usually is involved; however, patients can show multiple lobar involvement. Microscopically, cartilage plates in the bronchi are absent at the level where cartilage is expected. Identify the level at which the bronchus was resected to determine inappropriate cartilage development.
Overdistention of the airspaces within a pulmonary lobe is associated with air trapping and compressive changes in the remainder of the lung. A mediastinal shift away from the increased volume results in compression of the contralateral lung.
CLE almost always involves one lobe, with rates of occurrence as follows:
- Left upper lobe - 41%
- Right middle lobe - 34%
- Right upper lobe - 21%
CLE presents in the newborn period with a fluid-filled, overdistended lobe. The diagnosis can be made in utero or shortly after birth. CLE has an unexplained cause in some patients. In many patients, the absence of hypoplasia of cartilage rings of major and branch bronchi, with resultant bronchial collapse (bronchomalacia) during expiration, creates air trapping, resulting in CLE; however, in some patients the cause is unknown. Other possible causes of CLE are intrinsic parenchymal elastin defect and fibrosis of the interstitium, such that normal expiration and reduction of lobar volume cannot occur.
Congenital lobar emphysema has 2 forms:
- Hypoalveolar (fewer than expected number of alveoli)
- Polyalveolar (greater than expected number of alveoli)
Approximately 10% of patients have associated anomalies, primarily congenital heart disease.
Pulmonary arteries are normal in patients with CLE. The physician may observe subtle or obvious respiratory distress in an otherwise normal infant. He or she may observe asymmetry of chest and abdominal retractions on inspiration. Hypoxemia (in severely affected patients) may occur.
The thorax on the involved side is hyperresonant with decreased or absent breath sounds and transillumination. The diagnosis is often suspected upon in utero sonography if an overexpanded lobe filled with fluid is identified. Progressive respiratory distress from birth reflects the degree of emphysema; symptoms are at their worst in the first month. Occasionally, patients present in later childhood or adulthood.
Congenital lobar emphysema (ie, congenital lesion) should be differentiated from Swyer-James syndrome (ie, acquired pulmonary abnormality secondary to infection).
In Swyer-James syndrome, infection results in the following:
- Vascular compromise
- "Pruning" of peripheral pulmonary vasculature
- Small but hyperlucent lung (as the opposite, normal lung grows, the involved lung does not grow and appears more radiolucent)
Emergency surgical lobectomy was once considered the only treatment for CLE, but appropriate care may be nonsurgical in infants with only moderate respiratory distress.3,4
Maintaining ventilatory pressures and volume as low as possible avoids producing ventilator-related hyperexpansion of an affected lobe. Management by more conservative, gentle ventilation technique is often successful. Fewer surgeries result, because after diagnosis and initial treatment, the affected lobe only occasionally continues to expand. Infants with CLE who are not clinically in respiratory distress and who are able to feed and grow do not necessarily need surgery.5
Do not mistake CLE for a tension pneumothorax. Placement of a chest tube could result in lung puncture and bronchopleural fistula or persistent air leak.
Differential Diagnoses
Other Problems to Be Considered
Bronchial mucous plug with associated hyperaeration
Extrinsic bronchial compression
Agenesis/hypogenesis of contralateral lung
Bronchial hypoplasia with air trapping peripherally
Congenital cystic adenomatoid malformation6
More on Congenital Lobar Emphysema |
 Overview: Congenital Lobar Emphysema |
| Imaging: Congenital Lobar Emphysema |
| Follow-up: Congenital Lobar Emphysema |
| Multimedia: Congenital Lobar Emphysema |
| References |
| Next Page » |
References
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Azizkhan RG, Crombleholme TM. Congenital cystic lung disease: contemporary antenatal and postnatal management. Pediatr Surg Int. Jun 2008;24(6):643-657. [Medline].
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Doull IJ, Connett GJ, Warner JO. Bronchoscopic appearances of congenital lobar emphysema. Pediatr Pulmonol. Mar 1996;21(3):195-7. [Medline].
Congenital Lobar Emphysema. Virtual Children's Hospital, University of Iowa. http://indy.radiology.uiowa.edu/Providers. May 13, 1998.
Koontz CS, Oliva V, Gow KW, Wulkan ML. Video-assisted thoracoscopic surgical excision of cystic lung disease in children. J Pediatr Surg. May 2005;40(5):835-7. [Medline].
Lacy DE, Shaw NJ, Pilling DW, Walkinshaw S. Outcome of congenital lung abnormalities detected antenatally. Acta Paediatr. Apr 1999;88(4):454-8. [Medline].
Schwartz MZ, Ramachandran P. Congenital malformations of the lung and mediastinum--a quarter century of experience from a single institution. J Pediatr Surg. Jan 1997;32(1):44-7. [Medline].
Further Reading
Keywords
congenital lobar emphysema, CLE, emphysema, hyperexpansion of a lobe, lung herniation, polyalveolar emphysema, hypoalveolar emphysema
