Introduction
Diaphragmatic herniae are defects in the diaphragm that occur at anatomical points of weakness, and can be either congenital or acquired (traumatic).
Left untreated, abdominal contents will herniate into the thorax. As such, diaphragmatic hernia need surgical repair.
Acquired diaphragmatic hernia are most commonly causes by penetrating trauma and are beyond the remit of this article. This article will focus on congenital diaphragmatic hernias.
Figure 1 – View of the inferior surface of the diaphragm
Pathophysiology
Congenital diaphragmatic hernias are either Bochdalek hernia or Morgagni hernia.
Bochdalek hernia are more common, occurring in 1 in 5000 births, and develop as a result of a defect in the posterior attachment of the diaphragm. They are more typically left sided and around one third of cases occur concurrently with other congenital abnormalities.
Morgagni hernia are less common and occur as a result of herniation through the foramen of Morgagni (the space between xiphoid process and the costochondral attachments of diaphragm*). Compared to Bochdalek hernia, Morgagni hernia occur anteriorly and are more often right-sided.
*This space is where the internal mammary artery passes through the diaphragm to become superior epigastric artery
Clinical Features
Whilst some congenital hernia may be asymptomatic, many will present in the perinatal period.
If they occur in utero, pulmonary hypoplasia or respiratory compromise may be noted soon after birth, whilst in adults, features include dyspnoea, atypical chest pain, or clinical features of bowel obstruction.
The majority of Bochdalek hernia in adults will be small and around 27% will contain abdominal organs such as liver, bowel or spleen. Similar clinical features can occur with Morgagni hernia
Investigations
In neonates, the mainstay of investigation is with the plain film erect chest radiograph (CXR), which will show bowel loops (or any other abdominal viscera) herniated into the thoracic cavity (Fig. 2)
For adult patients, whilst initial diagnosis may be suspected on CXR, often CT imaging of the chest is performed (Fig. 3), as this is especially useful for pre-operative planning
Figure 2 – CXR showing bowel loops in the thorax from a diaphragmatic hernia in a neonate
Management
Surgical repair for both types is the only curative option. Repairs can be done either laparoscopically or open, depending on both hernia and patient factors
Intra-operatively, once the hernia is reduced and any hernia sac resected, the defect can be closed either through primary closure or with a mesh (depending on the defect location and size).
Figure 3 – Sagittal CT chest scan demonstrating a Morgagni hernia (arrow) containing intra-abdominal fat
Key Points
- Diaphragmatic herniae are defects in the diaphragm that occur at anatomical points of weakness and can be either congenital or acquired (traumatic)
- Congenital diaphragmatic hernias are either Bochdalek hernia or Morgagni hernia
- In utero, the can present with pulmonary hypoplasia or respiratory compromise, whilst in adults they can present with dyspnoea, atypical chest pain, or clinical features of bowel obstruction
- Surgical repair is the only treatment option available