Autumn bloats up like a fat orange pumpkin when she's in pain. When she throws out her back, when her arthritis is bothering her, whenever there is pain involved. Its not the same as a twisted stomach in her case. She's done this since 6 months old when she first slipped a disc. I don't know how you can tell in your dog if it is or isn't, but I can tell you some dogs puff up when in pain if it helps.