Diaphragmatic Hernia (Congenital)
- 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)
- 1:2,000 to 5,000 live births
- Left sided in 85–90%
- Right-sided and bilateral defects less common
- Familial recurrence 2%
Pregestational diabetes and alcohol use associated with increased risk
- 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.
- 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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