Life threatening conditions such as kidney failure, poisoning, painful abdomen etc.. (dogsymptomscure.com)
Pancreatitis canine symptoms include a very painful abdomen with abdominal distension and a «hunched up» appearance. (dog-health-guide.org)
For example, a tense painful abdomen could be a sign of pancreatitis, a large amount of hard stool in the lower abdomen could indicate constipation, a fever might indicate an underlying infection, and an abdominal mass could be a tumor. (lienanimal.com)