my two year old female had a similar problem runs etc, he prescribed the flagyl, dewormer, and a couple shots to stop the stomach spasms that cause the diahrea. There is a worm that is undectable that lives in stale water that dogs drink outside etc. its pretty common. A Really good vet would also prescribe a high protein dog food and some vitamin powder to put it on the food to help him gain the vitamins he lost while he was sick. The swelling I would think can be caused from lack of drinking and his fever but dunno, I would go to another vet.

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Panda and Brutis who owns their owner Paula!