Diaphragmatic eventration

Changed by Enzo Hulleman, 8 Sep 2022
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Disclosures - updated 8 Sep 2022: Nothing to disclose

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Diaphragmatic eventration refers to an abnormal contour of the diaphragmatic dome with no disruption to the diaphragmatic continuity. It typically affects only a segment of the hemidiaphragm, compared to paralysis/weakness where the entire hemidiaphragm is typically affected. 

Epidemiology

Associations

Unilateral eventration 5

Bilateral eventration 5

Clinical presentation

In newborns, eventration of the diaphragm is a recognised cause of respiratory distress. However in adults, it is often asymptomatic 6. 

Pathology

Diaphragmatic eventration may be congenital or acquired in nature. It occurs due to incomplete muscularisation of the diaphragm with a thin membranous sheet replacing normal diaphragmatic muscle. Over time this region stretches and on inspiration does not contract normally. 

Aetiology
Congenital

  • phrenic nerve agenesis

  • failure of myotomes to migrate to a localizedlocalised area in the diaphragm leading to abnormal muscularisation
Acquired
Location

Congenital eventration is frequently seen in the anteromedial portion of the right hemidiaphragm, while acquired eventration is frequently seen in the left hemidiaphragm. Total eventration is most commonly seen in the left hemidiaphragm 6. 

Radiographic features

Plain radiograph

Elevation of the affected portion of the diaphragm is usually seen as a smooth hump, while the remainder of the hemidiaphragm contour is normal. The frontal x-ray may show a 'double' diaphragmatic contour, which is easily confirmed on the lateral projection.

CT

There may be a sharp border between the eventrated portion and the remainder of the hemidiaphragm 4.

Differential diagnosis

Possible considerations on plain film include:

  • -<li><a href="/articles/beckwith-wiedemann-syndrome-2">Beckwith-Weidemann syndrome</a></li>
  • +<li><a href="/articles/beckwith-wiedemann-syndrome-2">Beckwith-Wiedemann syndrome</a></li>
  • -<li>failure of myotomes to migrate to a localized area in the diaphragm leading to abnormal muscularisation</li>
  • +<li>failure of myotomes to migrate to a localised area in the diaphragm leading to abnormal muscularisation</li>
  • -<li><a href="/articles/morgagni-hernia-2">Morgagni hernia</a></li>
  • +<li><a href="/articles/morgagni-hernia-3">Morgagni hernia</a></li>

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