eMedicine Specialties > Radiology > Pediatrics

Congenital Lobar Emphysema

Beverly P Wood, MD, MS, PhD, Professor, Departments of Radiology and Pediatrics, Division of Medical Education, Keck School of Medicine, University of Southern California

Updated: Dec 1, 2008

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.

(See Images in Multimedia Section.)

Related eMedicine Radiology topics:
Emphysema
Emphysematous Pyelonephritis
Pulmonary Interstitial Emphysema

Related Medscape topics:
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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)

Differential Diagnoses

Pneumothorax

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

Radiography

Two-year-old patient with respiratory distress shows left upper lobe hyperaeration.

A frontal radiograph of the chest in a neonate shows marked overdistention of the left upper lobe with mediastinal shift to the right.

Anteroposterior chest radiograph shows overexpansion of the right middle lobe in a patient aged 18 months with suspected asthma.

Lateral chest radiograph shows anterior herniation of the right middle lobe.

Lateral chest radiograph with mild midline herniation of the left upper lobe.

Findings

Techniques and findings

Radiography of the chest in anteroposterior and lateral projections identifies the involved lobe, the degree of involvement, and the effect on surrounding structures.⁷ If a decubitus position radiograph is obtained, the involved lung does not collapse.

A large, hyperlucent lung with attenuated but defined vascularity is observed. Compression of the remaining lung on that side, flattened hemidiaphragm, and widened intercostal spaces also are seen. An involved lung is seen herniated across the anterior midline. On a lateral view, the heart is displaced posteriorly with retrosternal lucency representing an anteriorly herniated lobe (see the 5 Images above).

The lobe is unchanged during exhalation or after placing the patient in the ipsilateral decubitus position.

Chest fluoroscopy shows fixed lung and hemidiaphragm on the involved side.

Radiographic appearance is characteristic of congenital lobar emphysema (CLE) and usually is not suggestive of other diagnoses.

Imaging pearls

• Be certain a mucous plug is not present, which can obstruct a bronchus, creating a "check valve" phenomenon that partially obstructs an airway.
• Similarly, extrinsic masses, such as a congenitally large pulmonary artery (as in the absence of the pulmonary valve), can create emphysema from partial bronchial obstruction.
• Usually, with careful image analysis, cystic lung disease does not mimic CLE; however, hypoplasia or agenesis of the contralateral lung may result in marked compensatory hyperexpansion of the lung, which can closely resemble CLE.

Computed Tomography

Computed tomography scan of the patient shows marked hyperaeration of the left upper lobe and mediastinal shift to the right.

Computed tomography scan indicates moderate hyperaeration of the right middle lobe.

Findings

Techniques and findings

Computed tomography scanning can provide details about the involved lobe and its vascularity, as well as information about the remaining lung.

CT scan shows a hyperlucent, hyperexpanded lobe (attenuated but intact pattern of organized vascularity) with midline substernal lobar herniation and compression of the remaining lung.⁸ Usually, the mediastinum is significantly shifted away from the side of the abnormal lobe (see the 2 Images above).

Magnetic Resonance Imaging

Findings

Techniques and findings

MRI can be used as an adjunct modality to evaluate vascular supply and distribution to the involved lobe but is not routinely employed. In congenital lobar emphysema, the abnormal lobe usually has a normal vascular supply.

Ultrasonography

Findings

Techniques and findings

In utero sonography may show a large, fluid-filled lobe; mediastinal herniation can be seen. A prenatal diagnosis of congenital lobar emphysema is not made as frequently as in other intrapleural fetal masses.

Variants include other causes of uneven lung expansion. In the neonate, a large pulmonary artery or mediastinal mass can compress the bronchus with overinflation of a lobe. Even the presence of a bronchial mucous plug can result in overinflation of a lobe. Infants with bronchopulmonary dysplasia often have uneven inflation of the pulmonary lobes related to bronchial cellular plugs or bronchial fibrosis, rendering the bronchus noncompliant.

Nuclear Imaging

Perfusion scan in right posterior oblique (RPO) projection shows virtually no perfusion of the right middle lobe.

Findings

Techniques and findings

Ventilation-perfusion scanning demonstrates characteristic results. Ventilation is initially diminished in the affected lobe, but ultimately, isotope retention is seen because of delayed emptying of alveoli in the emphysematous lobe. The markedly attenuated vascularity of the involved lobe results in decreased perfusion of the enlarged lobe (see Image above).

Intervention

Medicolegal Pitfalls

• Failure to schedule regular follow-up visits to ensure that pulmonary status does not worsen (if the decision is made to monitor congenital lobar emphysema [CLE]).
• Failure to carefully follow up with children with lower respiratory infection. This is important, as repeated infection may cause damage in an already overexpanded lobe of the lung.
• Failure to inform parents of the presence and potential complications of CLE. The presenting lobe may be the worst of a group of malacic bronchi, so even after definitive surgery, some children may continue with wheezing and prolonged expiratory phase with symptomatic additional small airway disease.

Multimedia

Media file 1: A frontal radiograph of the chest in a neonate shows marked overdistention of the left upper lobe with mediastinal shift to the right.

Media file 2: Computed tomography scan of the patient shows marked hyperaeration of the left upper lobe and mediastinal shift to the right.

Media file 3: Histopathology of congenital lobar emphysema with marked overdistention of all alveoli.

Media file 4: Anteroposterior chest radiograph shows overexpansion of the right middle lobe in a patient aged 18 months with suspected asthma.

Media file 5: Lateral chest radiograph shows anterior herniation of the right middle lobe.

Media file 6: Computed tomography scan indicates moderate hyperaeration of the right middle lobe.

Media file 7: Perfusion scan in right posterior oblique (RPO) projection shows virtually no perfusion of the right middle lobe.

Media file 8: Resected lobe is overexpanded and shows no other intrinsic abnormality.

Media file 9: Two-year-old patient with respiratory distress shows left upper lobe hyperaeration.

Media file 10: Lateral chest radiograph with mild midline herniation of the left upper lobe.

Media file 11: Computed tomography scanning demonstrates the characteristic appearance of polyalveolar congenital lobar emphysema of the right middle lobe. Overdistention is mild, and vascularity is fairly well developed. The left lung is compressed but not hypoplastic. Lung hypoplasia is almost invariably on the right.

Media file 12: Swyer-James syndrome. with growth decreasing in one lung after infection.

Media file 13: The left upper lobe is affected in 41% of patients with congenital lobar emphysema.

References

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2. Lin YC, Chang YK, Lu D, Shih TY. Congenital lobar emphysema mimicking cystic mass in a newborn. Acta Paediatr Taiwan. Jul-Aug 2007;48(4):220-2. [Medline].

3. Rothenberg SS. First decade's experience with thoracoscopic lobectomy in infants and children. J Pediatr Surg. Jan 2008;43(1):40-4; discussion 45. [Medline].

4. Chia CC, Huang SC, Liu MC, Se TY. Fetal congenital lobar emphysema. Taiwan J Obstet Gynecol. Mar 2007;46(1):73-6. [Medline].

5. Eber E. Antenatal diagnosis of congenital thoracic malformations: early surgery, late surgery, or no surgery?. Semin Respir Crit Care Med. Jun 2007;28(3):355-66. [Medline].

6. Azizkhan RG, Crombleholme TM. Congenital cystic lung disease: contemporary antenatal and postnatal management. Pediatr Surg Int. Jun 2008;24(6):643-657. [Medline].

7. Farrugia MK, Raza SA, Gould S, Lakhoo K. Congenital lung lesions: classification and concordance of radiological appearance and surgical pathology. Pediatr Surg Int. Sep 2008;24(9):987-91. [Medline].

8. Doull IJ, Connett GJ, Warner JO. Bronchoscopic appearances of congenital lobar emphysema. Pediatr Pulmonol. Mar 1996;21(3):195-7. [Medline].

9. Congenital Lobar Emphysema. Virtual Children's Hospital, University of Iowa. http://indy.radiology.uiowa.edu/Providers. May 13, 1998.

10. 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].

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12. 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].

Keywords

congenital lobar emphysema, CLE, emphysema, hyperexpansion of a lobe, lung herniation, polyalveolar emphysema, hypoalveolar emphysema

Contributor Information and Disclosures

Author

Beverly P Wood, MD, MS, PhD, Professor, Departments of Radiology and Pediatrics, Division of Medical Education, Keck School of Medicine, University of Southern California
Beverly P Wood, MD, MS, PhD is a member of the following medical societies: American Academy of Pediatrics, American Association for Women Radiologists, American College of Radiology, American Institute of Ultrasound in Medicine, American Medical Association, American Roentgen Ray Society, Association of University Radiologists, Radiological Society of North America, and Society for Pediatric Radiology
Disclosure: Nothing to disclose.

Medical Editor

S Bruce Greenberg, MD, Professor of Radiology, University of Arkansas for Medical Sciences; Consulting Staff, Department of Radiology, Arkansas Children's Hospital
S Bruce Greenberg, MD is a member of the following medical societies: Radiological Society of North America
Disclosure: Nothing to disclose.

Pharmacy Editor

Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.

CME Editor

Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute
Robert M Krasny, MD is a member of the following medical societies: American Roentgen Ray Society and Radiological Society of North America
Disclosure: Nothing to disclose.

Chief Editor

John Karani, MBBS, FRCR, Consulting Staff, Department of Radiology, King's College Hospital, London
Disclosure: Nothing to disclose.

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