This morning his temperature is back up and he is acting sick again. The vet said she gave him a small dose of steroids yesterday and that may be why he was better. She said that he has been on heavy antibiotics for 4 days now and he should be improving. She suggested that it may very well be lymphoma, even thought the ultrasound didn't raise any alarm in that direction. We are currently waiting to see if he can have a endoscopy today or not. If he can't get one today, they may try syringe feeding him till tomorrow when he would be able to have the biopsy. A biopsy can tell us if he has IBD or they may just run into a mass and know it is cancer. IBD is treatable with steroids, but she doesn't want to do heavy dose of that because it can change the biopsy results.
Pray for IBD.