Images: 3 radiographs of the thorax are provided for review.
There is a large gas-filled structure with a thin soft tissue opaque rim occupying the entire left hemithorax and extending across midline, with a resultant marked rightward mediastinal shift. There are several mineral opacities throughout the mid to ventral aspect of the gas dilated structure on the lateral views, which are poorly defined on the ventrodorsal view, although possibly on midline. The left diaphragmatic crus is indistinct. The cardiac silhouette appears normal in size. The pulmonary vessels are poorly defined. There is a large region of soft tissue opacity throughout the right hemithorax on the ventrodorsal view, some of which likely represents collapsed lung and mediastinum. An interstitial pattern is noted throughout the small volume of aerated lung within the right hemithorax. The serosal margin detail throughout the abdomen is absent with lack of visualization of the stomach.
The large gas-filled structure with a thin soft tissue opaque rim is most consistent with a severely gas distended stomach with a small volume of mineral opaque luminal debris, herniated through a congenital or traumatic rent in the diaphragm. The marked mediastinal shift is consistent with a tension gastrothorax.
A tension gastrothorax results when the stomach herniates through a defect of the diaphragm, either traumatic or congenital in origin. Gas becomes trapped in the stomach, and as the stomach progressively distends with air, it causes compression and resultant collapse of the lung, in a similar fashion as a tension pneumothorax. There is reduced venous blood return to the heart, which results in hypovolemic shock.
Without a history of trauma in this patient, a congenital diaphragmatic rent is most likely, and the stomach likely herniated through the congenital diaphragmatic defect during forceful abdominal contractions while vomiting. This is a surgical emergency and the stomach should be decompressed with orogastric intubation prior to surgical repair.
The patient decompensated quickly and was euthanized. At necropsy there was a large tear in the diaphragm on the left side with the stomach, spleen, some intestines, omentum, and a portion of the liver all herniated through the diaphramatic defect. There was no evidence of trauma.
Zarelli, M et al. What is your diagnosis? Tension gastrothorax. J Am Vet Med Assoc. 2010 Apr 1; 236(7): 733-4.