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CONGENITAL DIAPHRAGMATIC HERNIA
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Disorder characterized by pulmonary hypoplasia due to intrauterine compression of the developing lungs by herniated viscera.
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Incidence is 1000 per year (1:2000–1:5000 live births); female:male 2:1
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7–10% gestations end in fetal demise
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Defects more common on left side (about 80%)
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Associated with anomalies (10–35%) including: Central nervous system (CNS) lesions, tracheobronchial abnormalities, omphalocele, cardiovascular (CV) lesions, skeletal and syndromes (trisomy 13, 18, 21, Beckwith–Weidemann, Brachmann–de Lange, and Pallister–Killian, among others)
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Unknown currently, though several pharmacologic and environmental factors have been implicated, including a possible role for vitamin A deficiency and/or retinoid regulated gene defects
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Embryologic theory: Lack of closure of the posterolateral pleuroperitoneal canals in the 8th week of gestation fails to separate the thoracic and abdominal cavities
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Portions of the diaphragm and pulmonary parenchyma arise from thoracic mesenchyme and if disrupted may lead to absence of part of hemidiaphragm and pulmonary hypoplasia
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Most cases are sporadic; familial cases occur (2%)
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DIFFERENTIAL DIAGNOSIS
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Cystic adenomatoid malformation, cystic teratoma, pulmonary sequestration, bronchogenic cyst, neurogenic tumors, primary lung sarcoma, diaphragmatic eventration
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Herniation of abdominal contents into thoracic cavity through posterolateral foramen of Bochdalek
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Diaphragmatic defect may be small or may include entire hemidiaphragm
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Pulmonary vasculature has increased muscularization of pulmonary arterioles and decreased branching of vessels resulting in pulmonary hypertension
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Lungs are hypoplastic due to chronic compression, with decreased numbers of bronchial branches on both ipsilateral and contralateral sides
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CLINICAL MANIFESTATIONS
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Most patients present with respiratory distress within the first hours of life secondary to severe pulmonary hypoplasia and associated pulmonary hypertension
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10–20% may have delayed presentation characterized by less severe pulmonary hypoplasia and pulmonary hypertension, as well as gastrointestinal (GI) symptoms (e.g., vomiting, abdominal pain, constipation)
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Pneumothorax
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On exam: Absence of breath sounds; bowel sounds in chest; scaphoid abdomen; increased anterior-posterior diameter of chest; shifted heart sounds
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Prenatal ultrasound able to detect defect as early as 11th week, mean gestational age (GA) at diagnosis is 24 weeks; accuracy has been reported to be between 40 and 90%
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Antenatal diagnosis is associated with more severe defects and a worse prognosis; if diagnosed by ultrasound, fetal MRI should be performed
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During fetal period, a lung-head ratio (LHR, area of contralateral lung to fetal head circumference by ultrasound) of <1 indicates severe disease
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Observed-to-expected LHR (O/E LHR) accounts for changes in LHR with GA, and O/E LHR <25% suggests severe CDH
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Echocardiography and amniocentesis to detect other anomalies
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Chest x-ray
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Initial Medical Management
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Initial resuscitation includes correction of hypoxia, hypercarbia, acidosis, and hypothermia as they increase pulmonary vascular resistance and ...