Diaphragmatic Hernia (Congenital)

Descriptive text is not available for this imageBASICS

DESCRIPTION

  • Defect in the diaphragm allowing herniation of abdominal contents into the thoracic cavity, leading to varying degrees of pulmonary hypoplasia, and pulmonary hypertension
  • Bochdalek hernia
    • Posterolateral location
    • Most common congenital diaphragmatic hernia (CDH)
  • Morgagni hernia
    • Anteromedial location

EPIDEMIOLOGY

  • 1 to 4 per 10,000 births
  • Left sided in 85–90%
  • Right-sided and bilateral defects less common
  • Familial recurrence 2%
  • Mortality rates range from 28% to 50%.

ETIOLOGY

  • Unknown
  • Most cases thought to occur sporadically.
  • Animal models suggest vitamin A deficiency and decreased retinol-binding protein as playing roles in CDH pathogenesis.

RISK FACTORS

  • Advanced maternal age
  • Maternal pregestational diabetes
  • Maternal alcohol or tobacco use during pregnancy
  • Definitive risk factors challenging to identify—disease most accurately classified as a sporadic developmental anomaly

PATHOPHYSIOLOGY

  • Despite ongoing research, diaphragmatic development remains incompletely understood.
  • Embryogenesis of the diaphragm begins during weeks 3 to 5 of gestation.
  • The diaphragm is a skeletal muscle thought to be made up of four embryonic sources:
    • Somites: the source of the muscular components of the diaphragm
    • Pleuroperitoneal folds (PPFs): bilateral mesodermal structures that form the dorsolateral edges and may be critical to many components
    • Posthepatic mesenchymal plate (PHMP): forms in close contact with the peritoneal organs; may play critical role in advancement/closure of the diaphragm and pathologic diaphragmatic development
    • Septum transversum: the potential origin of the separation of the thoracic and abdominal cavities and a possible embryologic source of the central tendon
  • Roughly 95% of CDH occur in a posterolateral position (Bochdalek) and 80% on the left side.
  • Defining feature of CDH is incomplete development of the diaphragm.
    • Allows abdominal contents into the thoracic cavity and compromise lung development
    • Abnormal lung development manifests as bilateral pulmonary hypoplasia and persistent pulmonary hypertension which are the major sequelae responsible for the morbidity and mortality of CDH.
    • Developing lungs show impaired branching morphology with acinar hypoplasia, decreased terminal bronchioles, and failed alveolarization.
    • Pulmonary hypertension is a consequence of structural abnormalities of the pulmonary vasculature. Reduction of the pulmonary vascular bed, pulmonary vascular remodeling, and altered vasoreactivity contribute to pulmonary hypertension.

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 the following:
    • Beckwith-Wiedemann
    • Trisomies 13, 18, and 21

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