Diaphragmatic Hernias Workup

Updated: Nov 19, 2021
  • Author: Nicola Lewis, MBBS, FRCS, FRCS(Paed Surg); Chief Editor: Eugene S Kim, MD, FACS, FAAP  more...
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Laboratory Studies

Antenatal studies to be considered include the following:

  • Amniocentesis for karyotype analysis should accompany a diagnosis of congenital diaphragmatic hernia (CDH)
  • Maternal serum alpha-fetoprotein (AFP) may be low in cases of CDH

Postnatal studies to be considered include the following:

The Score for Neonatal Acute Physiology-II (SNAP-II score) has been suggested as a usefull means of assessing the risk of mortality and the need for extracorporeal membrane oxygenation (ECMO) therapy in neonates with CDH. [22] The SNAP-II score is determined on the basis of arterial blood pressure, pH, ratio of arterial oxygen tension (PaO2) to fraction of inspired oxygen (FiO2), body temperature, diuresis, and seizure activity.


Chest Radiography

An early chest radiograph is obtained to confirm the diagnosis of CDH. Findings include loops of bowel in the chest, a mediastinal shift, a paucity of bowel gas in the abdomen, and the presence of the tip of a nasogastric tube in the thoracic stomach (see the image below). Repeated chest radiography may reveal a change in the intrathoracic gas pattern. Right-side lesions are difficult to differentiate from diaphragmatic eventration and lobar consolidation.

Radiograph of an infant with congenital diaphragma Radiograph of an infant with congenital diaphragmatic hernia. Note shift of the mediastinum to the right, air-filled bowel in the left chest, and the position of the orogastric tube.

Ultrasonography and Echocardiography

Level III ultrasonography (US) and echocardiography should accompany a diagnosis of CDH. Antenatal echocardiography may identify cardiac anomalies (more commonly, ventricular hypoplasia, atrial septal defects, and ventricular septal defects). [23]  Decreased left ventricular mass, poor ventricular contractility, pulmonary and tricuspid valve regurgitation, and right-to-left shunting may be seen. Repeated echocardiography is recommended to measure changes in the pulmonary artery pressure, left-to-right shunt, and flow across the ductus arteriosus.

In a study involving 18 neonates with CDH, Tanaka et al found the use of M-mode imaging to measure diastolic wall strain to be a useful method for evaluating the diastolic function of CDH patients. [24]

In centers where fetal intervention and postnatal management protocols are determined by antenatal assessment of pulmonary hypoplasia, the lung-to-head ratio (LHR) and the lung-to-thorax transverse ratio (L/T) are calculated.

One definition of the LHR is the area of the contralateral lung (the product of the two longest perpendiculars) divided by the head circumference at the four-chamber view. Standardization of LHR measurements may lead to improved prediction of outcomes in neonates with isolated CDH. [25]  L/T is the ratio of the area of the contralateral lung to the area of the thorax at the four-chamber view on US. [26, 27]

US reveals polyhydramnios, an absent intra-abdominal gastric air bubble, mediastinal shift, and hydrops fetalis. US demonstrates the dynamic nature of the visceral herniation observed with congenital diaphragmatic hernia. The visceral hernia has moved in and out of the chest in several fetuses.

Differential diagnoses on antenatal US are as follows: