Thursday, 20 August 2015

xrayoftheweek 33: previous gastric surgery and now chest pain - why?

The #xrayoftheweek is this chest x-ray in a man who had previously undergone gastric surgery (Roux-en-Y gastric bypass as a second procedure for reflux), and presented with chest pain with ST segment depression on his ECG. What do you see and what might this be the result of?

The xray shows gas outlining the heart, with the pericardium being "lifted" off the heart. This is a "pneumopericardium", shown particularly well on this coronal reformatted CT:

Following detection of the pneumopericardium, he had a CT with oral contrast to look for a possible site of communication with the GI tract. These are coronal and sagittal images from that study:

The coronal image shows a track between the gastric pouch and the gas filled pericardium, through the diaphragm. The sagittal image confirms that some of the administered oral contrast has pooled in the posterior (dependent when patient is lying on the CT scanner table) aspect of the pericardium. The diagnosis of a gastropericardial fistula was made. The prevailing theory as to the cause of this is ongoing peptic ulceration and inflammation, with ischaemia as a possible additional factor.

Pneumopericardium is a surgical emergency as the development of cardiac tamponade by raised pericardial pressures must be avoided as a matter of urgency. Following the CT, he was taken to theatre and an on-table endoscopy confirmed a fistula track between the gastric pouch and pericardium, with food debris seen within the pericardial sac. He underwent a total gastrectomy and formation of an oesophagojejunostomy, and windowing of the pericardium.

Learning point:
Identification of pneumopericardium should prompt emergent referral to the surgeons and a CT of the chest and abdomen with oral contrast should be undertaken. Oesophago- and gastro-pericardial fistulae are recognised complications of oesophagogastric surgery and peptic ulceration.

Note: these images and a more full description with references are also found in a publication I have co-authored with surgical colleagues in BMJ Case Reports, I have permission to share these images.