Parents have a 12yo lab that started limping. Took her to the vet, left leg was swollen and she had a fever. Xrays showed nothing wrong with bones or joints. Gave her antibiotics and pain meds. She was getting better then got a lot worse. Took her back yesterday. The swelling has spread, whole rear leg is swollen. Still running a fever. More antibiotics and a antibiotic shot.
What could be causing this? Lyme disease test was met, no signs of bites or cuts.