Ok, it is mixed:

It is the kidneys. But a very early stage. I did not get it completely (as I haven't seen the vet myself but in his bloodwork a value that should be 46 and is considered normal until 83 is 89. This gets dangerous once the same value is 140 or more. So he is above his limits (it may be the purine in the blood but who cares) but we got it early. He is getting 3 steroid injections, the first was Friday and after that the doc will check again.

He was first a very good boy being calm when he got the injection but then immediately and with no warning jumped on his dad's shoulders.

He has to eat less purine. The doc recommended that we mix a rice in his normal food. He says it will be easier to get him to eat that than the special kidney diet. However I will get more information about food- there may be seveal options.

Filou is not feeling sick- he is just himself.

Thank you for all your concerns and prayers. I have no idea how we could deal with this if we hadn't all of you to hold our hands- virtually at least