Continuous diaphragm sign

   July 21, 2020  Posted in Gastrointestinal Tract

Case contribution: Dr Radhiana Hassan

Clinical:

  • A 46 years old man
  • Initially presented with jaundice, ERCP and stenting done in another hospital
  • Presented with abdominal pain 2 days after being discharged following the above-said procedure
Chest radiograph in erect PA view

Radiographic findings:

  • There is a lucent curvilinear line (yellow arrow) outlining right and left hemidiaphragm in continuity without its normal obliteration at midline region
  • No obvious free air at subdiaphragmatic region
  • No lucent line outlining the heart or mediastinum
  • No active lung lesion. No pneumothorax or pleural effusion.
  • Air pockets seen at right lateral chest wall (red arrow)

Radiographic diagnosis: Continuous diaphragm sign

Discussion:

  • Continuous diaphragm sign is a radiographic sign seen on chest radiograph
  • It is described as continuous visualization of the diaphragm across the midline which is normally not seen due to presence of free ga
  • If the lucency is above the diaphragm then the free gas is within the mediastinum (pneumomediastinum) or pericardium (pneumopericardium).
  • If the lucency is seen below the diaphragm, the free gas is within the peritoneum (pneumoperitoneum) as seen in this case.

Progress of patient:

  • Abdominal radiograph shows pneumoretroperitoneum (image shown below).
  • CT scan abdomen performed confirmed presence of pneumoperitoneum, pneumoretroperitoneum and subcutaneous emphysema (selected images below).
  • No pneumothorax or pneumomediastinum seen.
  • Extensive subcutaneous emphysema with pneumoretroperitoneum and  pneumoperitoneum are known complications post ERCP especially if sphincterotomy is performed.
  • Patient was managed conservatively and recovered well.
  • A repeat ERCP done shows oedematous sphincterotomy scar which is well healed
  • Stent was removed.
  • Planned for laparoscopic cholecystectomy.
Abdominal radiograph shows extensive free gas outlining the renal and retroperitoneum (white arrows), the right psoas outline (blue arrows) and subcutaneous emphysema (yellow arrowheads).

 

CT scan abdomen in axial plane; lung window (upper row) and soft tissue window (lower row) confirmed the retroperitoneal air (red arrow), pneumoperitoneum (blue arrow) and subcutaneous emphysema (yellow arrow).

 

References/further reading:

1) https://radiopaedia.org/articles/continuous-diaphragm-sign

2) Pneumomediastinum revisited;Zylac CM, RadioGraphics 2000; 20:1043–1057.

Author: radhianahassan