Congenital Diaphragmatic Hernia

congenital diaphragmatic hernia

This coronal obstetric ultrasound (head to right of image, thorax centre, abdomen left) shows the stomach and heart both within the thorax. The diaphragm can be seen as a vertical curved echogenic line separating abdomen and thorax. The heart is displaced to the foetus’ right.
Congenital diaphragmatic hernia is due to failure of fusion of one of the pleuroperitoneal canals at around 8 weeks gestation. It is more common on the left (75-90%). The hernia may contain stomach, intestines, liver or spleen. CDH detected antenatally are often large, and perinatal mortality may be as high as 80%. Mortality is predominantly due to pulmonary hypoplasia, thought to be due to mass effect on the developing lung.
The sonographic findings of CDH are: cardiomediastinal shift; stomach at same transverse level as heart; and portal veins in thorax (Doppler). CDH should be included in the differential diagnosis of right thoracic mass, as liver may simulate cystic adenomatoid malformation or pulmonary sequestration. Signs suggesting a poor prognosis are: large size; early gestational age at diagnosis; intrathoracic liver; small contralateral lung; associated abnormalities; and bilateral CDH. Lung-head ratio (2 axial diameters of lung multiplied, and divided by head circumference) may be used to give an indication of pulmonary hypoplasia. LHR < 1.0 is associated with a poor prognosis, and >1.4 a good prognosis. Foetal MRI may be helpful in further assessing the hernia and associated pulmonary hypoplasia.
Foetuses with an antenatal diagnosis of CDH should be delivered in a tertiary referral centre with access to neonatal intensive care and paediatric surgical facilities.

Reference: Callen PW. Ultrasonography in Obstetrics and Gynaecology. 4th edition. WB Saunders, 2000

Credit: Dr Laughlin Dawes