Bronchopulmonary Dysplasia
Chronic Lung Disease of Infancy

General Considerations

• First described as a chronic lung disease seen in premature newborns treated for respiratory distress syndrome (RDS) with supplemental oxygen and mechanical ventilation for at least one week
• It is now recognized that bronchopulmonary dysplasia (BPD) may complicate other types of neonatal lung disorders such as meconium aspiration syndrome and pneumonia
• Common to almost all causes is oxygen administered under positive pressure
• One definition involves an oxygen requirement at 28 days of life to maintain arterial oxygen tensions >50 mm Hg accompanied by abnormal chest radiographs
• Rarely occurs in infants > 1250 g and in infants born after 30 weeks gestation
  • Most common in those with a birth weight of  < 1000g, born at 22-32 weeks of gestation
• Incidence of bronchopulmonary dysplasia defined as a continued need for oxygen at 36 weeks (corrected age) is 30% for infants <1000g at birth
• Potentiating factors
  • Pulmonary edema
  • Infection
  • Poor nutritional status

Clinical Findings

• Tachypnea and tachycardia
• Retractions
• Oxygen desaturation
• Weight loss

Imaging Findings

• It may be impossible to distinguish the early stages of bronchopulmonary dysplasia from the later stages of respiratory distress syndrome (hyaline membrane disease)
• Coarse, irregular, rope-like, linear densities
  • Represents atelectasis or fibrosis
• Lucent, cyst-like foci
  • Hyperexpanded areas of air-trapping
• Hyperaeration of the lungs
• Shifting atelectasis
• Episodes of aspiration or pulmonary edema
• Superimposed pneumonia
• Changes of bronchopulmonary dysplasia will revert to normal on the chest radiograph in most patients after the age of two

Differential Diagnosis

• Pulmonary interstitial emphysema (PIE) may look identical
  • Smaller air-containing spaces in PIE (bubbly appearance)
• Left-to-right shunt such as a patent ductus arteriosus
• Infection, especially with non group A beta streptococci
• Congestive heart failure and pulmonary edema

Treatment

• Prevention of hypoxemia and anemia
• Diuretics
• Systemic corticosteroids
• Optimal nutrition

Complications

• Sudden infant death
• May go on to develop pulmonary arterial hypertension
• Increased risk of pulmonary infection
• Development of asthma

Prognosis

• With the use of surfactant replacement and antenatal steroids, survival has improved
• Main determinant of chronic morbidity is development of obstructive airway disease
  • Demonstrated by a decreased forced expiratory flow (FEF)
  • Increased airway reactivity
  • Increased residual volume with a normal total lung capacity

Bronchopulmonary Dysplasia. The lungs are usually overaerated. There are diffuse rope-like densities separated in some areas by zones of hyperlucency. The densities may be coalescent in many areas. The heart borders can be completely obliterated.
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Radiologic Clinics of North America Wood, B. The Newborn Chest  31:2 May 1993
Radiology of the Pediatric Chest   Felman, A.  McGraw-Hill  1987
Bronchopulmonary dysplasia eMedicine  Driscoll, W and Davis, J
Am. J. Respir. Crit. Care Med., Volume 163, Number 7, June 2001, 1723-1729 Bronchopulmonary dysplasia Jobe, A and Bancalari, E