Congenital thoracic disorders

Congenital lung lesions

• Bilateral agenesis of lungs
  • Fatal
• Unilateral agenesis of lungs
  • More common on left (70%)
  • >2:1 male to female ratio
• Hypoplasia of the lungs
  • Occurs with interference to the development of the alveolar system during the last 2 months of gestation
  • Most frequently a/w Bochdalek hernia, but also oligohydramnios, prune-belly syndrome, scimitar syndrome, and dextrocardia
• Hyaline membrane disease (or infant respiratory distress syndrome)
  • Frequent in premature infants and diabetic mothers
  • Immature surfactant system, leading to congested lungs with a deep purple gross appearance
  • Frequently leads to pneumothorax

Congenital cystic lesions

• Generally occur as a result of separation of the pulmonary remnants from airway branching
• May require resection
• Bronchogenic cyst
  • Arises from a tracheal of bronchial diverticulum, which becomes completely separated from the trachea
  • Symptoms may arise from compression of adjacent airways and from infection
  • Seen on CT as a homogenous, well-circumscribed mass adjacent to the trachea
  • Infected cysts have an air-fluid level
  • Excise when symptomatic
• Lobar emphysema
  • Intrinsic or extrinsic airway obstruction leading to the creation of a 'ball-valve' mechanism and subsequent air trapping
  • Rarely occurs after six months of age
  • Treatment is lobectomy
• Congenital pulmonary airway malformations (CPAM)
  • Result from abnormalities in branching morphogenesis of the lung
  • Stocker classification from 0-4
  • Lung has the appearance of Swiss cheese and feels like a large rubbery mass
  • Strongly associated with malignancy, in particular pleuropulmonary blastoma
• Bronchopulmonary sequestration
  • An area of embryonic lung tissue, separate from the tracheobronchial tree, which receives blood supply from an anomalous systemic artery from the aorta, not the pulmonary artery
  • Occurs secondary to an accessory lung bud, caudal to the normal lung
• Cystic fibrosis
  • Autosomal recessive
  • Excessively thick mucus leads to recurrent infections, bronchitis and bronchiectasis
  • Pneumothorax may occur secondary to air trapping
  • Lung failure is the most frequent cause of death
  • Consider bilateral lung transplantation when the disease rapidly progresses and the remaining pulmonary reserve is low

Congenital abnormalities of the trachea and bronchi

• Oesophageal atresia with trache-oesophageal fistula
  • Separate topic
• Bronchial atresia
  • Lung tissue distal to the atresia expands and becomes emphysematous as a result of air entry through collateral airways/pores
  • No exit for air or mucus - emphysema from air trapping, or mucocoele may result
  • Most frequently involves left upper lobe
• Tracheal agenesis
  • Fatal
• Tracheal stenosis
  • Separate topic
• Tracheomalacia
  • Marked variation of tracheal lumen with inspiration and expiration (defined by collapse >70% of lumen)
  • Stent placement may  be required
  • Most often actually seen in adults with COPD

Congenital vascular disorders

• Scimitar syndrome
  • Hypoplastic right lung with drainage of the pulmonary vein to the IVC
• Pulmonary AVMs
  • Bypass the pulmonary capillary bed, resulting in a right-to-left shunt
  • One third have hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu syndrome)
  • Consider in the differential for any patient unexplained haemoptysis after routine imaging and bronchoscopy
• Pulmonary vascular sling
  • Anomalous or aberrant left pulmonary artery, which causes airway obstruction, and is associated with other abnormalities
• Vascular rings
  • Double aortic arch, etc