Epidemiology
0.08 - 0.45 per 1000 births in world literature(1 per 2688 live births)
Aetiology
Majority are sporadic - only 2% occurring with familial asociation
Rare associations with teratogens
80% left sided and majority isolated
20% Can occur as part of a syndrome.
Antenatal Diagnosis 2D ultrasound
Abnormal thoracic views in transverse plain
Stomach seen at same level of 4CV
Mediastinal shift
Other abdominal contents present in chest - bowel and ?liver
Colour Doppler can show portal and hepatic veins above diaphragm
Polyhydramnios
CDH- Ultrasound Prognostic Criteria
First goal of a lung assessment method is to predict viability and requires to be performed < 26 weeks
Determination of "liver up" using 2D/Colour
Estimation of the residual right lung volume using the lung:head ratio (LHR)
3D Power Doppler of pulmonary vasculature- measures vascular resistance and thus function
Lung to head Ratio (LHR)
Two dimensional measurement of the contralateral lung by ultrasound at the transaxial level of the 4 chamber view in diastole.
Multiply these dimensions and divide by HC
Observed/Expected ratios can predict severity
References
Deprest et al Progress in intrauterine assessment of the fetal lung and prediction of neonatal function UOG 2005;25:108-111
Metkus et al Sonographic predictors of survival in fetal diaphragmatic hernia. J Ped Surg 1996 31;48-52