Yesterday I had to put my cat to sleep but I wanted to point out
something.

For years we couldn't figure out why she was going outside of the
litter box after years of using the box.  (She was 18 years old,
had her since she was 8 weeks old.)  

Well now we know.   Last week her kidney levels were very high,
we tried an intrevenous drip to bring it down, alas she got
progessively worse, and yesterday I had to put her to let her
go.  She stopped eating, was having trouble walking,
and seemed to know the end was near.

But the point here is for years the vets/behaviorist and I thought
it was behavioral, the tests always came back normal.  Now the
tests show an extremely high kidney level.