Impaction

Impaction is a blockage of the gut, most often from an amphibian swallowing loose substrate (like gravel) along with its food — a common, avoidable, and potentially fatal problem.

It is why terrestrial frogs and salamanders are kept on soft, non-swallowable substrate (moist coco fibre or topsoil, never gravel), and why you feed with tongs or off a dish. A bloated animal that has stopped passing waste needs a vet.