Diaphragmatic Hernia (Congenital)

Basics

Description

  • Defect in the diaphragm allowing herniation of abdominal contents into the thoracic cavity, causing varying degrees of pulmonary hypoplasia
  • There are four types of congenital diaphragmatic hernia (CDH):
    • Bochdalek hernia (posterolateral location)
    • Morgagni hernia (lateral retrosternal location)
    • Pars sternalis (medial retrosternal)
    • Anterolateral

Epidemiology

  • 1:2,000 to 5,000 live births
  • Left sided in 85–90%
  • Right-sided and bilateral defects less common
  • Familial recurrence 2%

Risk Factors

Pregestational diabetes and alcohol use associated with increased risk

Pathophysiology

  • Diaphragm arises from four elements and is complete by 8 weeks’ gestation.
    • Septum transversum, which becomes the central tendon of the diaphragm
    • Pleuroperitoneal membranes, which extend from the lateral body wall and fuse with the septum transversum and esophageal mesentery
    • Mesentery of the esophagus, which becomes the crura of the diaphragm
    • Lateral body wall from which myocytes migrate to muscularize the diaphragm
  • Posterolateral (Bochdalek defect) in 70%, anterior (Morgagni) in 25–30%, central in 2–5%
  • Main problem concerns pulmonary hypoplasia, which results in pulmonary hypertension.
    • Smaller lungs with fewer airway branches, fewer alveoli per terminal lung unit, and decreased surfactant production
    • Decreased pulmonary vascular surface area and smaller muscular arterioles with abnormal vasoreactivity results in pulmonary hypertension.
  • Both ipsilateral and contralateral lungs are hypoplastic, worse on ipsilateral side.
  • Degree of pulmonary hypoplasia and pulmonary hypertension determines illness severity both in acute and chronic settings.

Etiology

  • Unknown
  • Most cases occur sporadically.
  • Experimental rat models suggest role of vitamin A deficiency in pathogenesis.

Commonly Associated Conditions

40–50% of cases associated with another type of congenital malformation

  • Cardiac: 10–35%
  • Genitourinary: 23%
  • Gastrointestinal malformations: 14%
  • Central nervous system abnormalities: 10%
    • Approximately 10% of cases with associated congenital anomalies have a syndrome.
    • Associated syndromes include Beckwith-Wiedemann and trisomies 13, 18, and 21.

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