Temperature of 106...

We adopted an ex stud cat about 8 months ago, he is 10 years old and just adorable. Over the last few days he has been really quiet, off his food and uninterested in life so we took him to the vet. He has a temp of 106 and she gave him a shot of antibiotic and an antiinflammatory. He started eating when we got home and perked up a bit. She took his temp again 24 hours later and it had dropped to 105.5. He has started to miss his litter tray, squatting and have little poos - either runny or undigested food (very unlike him as he is a very clean cat). She gave him more shots and we are keeping an eye on him and taking him back on sunday morning. We are also running basic blood tests to see if anything can be picked up. This morning he is the same, still subdued and miserable. I hope it is just a virus and he will quickly recover. Anyone had similar experience?

Have they done bloodwork?

The litterbox issues and the subdued behavior are almost certainly related to the fever. Calicivirus, among many others, can cause high fevers. My kitty also has a high fever tonight (though not quite as high), and we discovered that he may have been exposed to Calicivirus earlier in the week.

I would not wait until Sunday. High fevers can affect a cat's appetite and thirst. With a virus, supportive therapy (like subcutaneous fluids) is important. I know that Spot refuses to eat or drink, and he was dehydrated when I took him into the vet. He's going back first thing in the morning, probably for more fluids. I would be very conservative and take him back sooner if I were you, especially since he is an older kitty.

Yes - the vet is going to ring me this morning with the basic test results then after the weekend send a sample to the lab