Gastric torsion is the twisting of the stomach at both the entrance and exit. It is most common in deep chested breeds such as the Great Dane, Bloodhound and German Shepherd. My experience of it is in German Shepherds. In all the cases I have heard of in GSDs, the dog has been past middle age. I had the experience with two of my GSDs, one was ten and one nine.
It is not know n what the cause is, although there are various theories. One is that sudden movement or exercise after feeding can cause it. Another is, if the spleen is enlarged, it can cause twisting. Another , over production of gas.
I was always an avid reader of the dog papers, so knew the symptoms, so I was able to phone the vet and say I was on my way and what was wrong. The symptoms were the same in both cases. They were:- attempted vomiting with no result, white foam drooling from their mouths, visible distension of the abdomen and obvious distress, whining etc.
The first time it happened was in 1980, with a ten year old.He showed symptoms within two hours of eating. He had to have his spleen removed, which is usual, but made a full recovery. The second time was in 1996, with a nine year old. It was more than two hours after feeding and i had already put him in his kennel for the night, when I heard him whinging. He also had to have his spleen removed and also made a full recovery, although somewhat slower.
Remember, torsion can happen many hours after feeding, so be on the look out at all times. Better a false alarm than a dead dog. Never feed a dog and immediately leave.