Hoping someone will have some helpful insight for us.

Our 7-yr old neutered male cat has been defecating in the house for
the past 4-5 weeks now. It was happening once or twice a week but now,
it's almost every day. He urinates in his box.

We brought him to the vet 2 weeks ago and they cleaned out his anal
sacs (which were full) and did a CBC - results were normal. The next
day, he pooped everywhere again. Then, nothing for a week. We were
resigned to a behavior problem (we have a 13-month old who started
walking around the same time as the inappropriate elimination started)
and made an appointment with an animal behavior specialist.

But earlier this week, we saw the whole poop scenario from start to
finish and realized that he was in pain when passing the stool. He
meowed really loudly and insistently, panted and then, judging by his
awkward position, passed the stool in discomfort. Usually, after the
meowing, he runs around like a bat out of hell dropping poop
throughout the house (on the hardwood floor and on the beds). I was
interpreting the meowing as cries for attention (I was usually tending
to the baby when it happened) and the poop dropping as resentment. So,
when this poop crisis started, we made sure we gave the cat more
attention, never ignored his requests to watch him eat and did our
best to make sure the baby wasn't stressing out the cat. After seeing
him in pain the other morning, we have to conclude that the problem is
medical. We took him back to the vet.

The vet checked him out again and didn't feel anything amiss. When I
mentioned mucous on his stool, he said that that usually indicates
irritation in the bowel. He suggested a new diet (Medi-Cal
hypoallergenic/gastro), meds (Apo-Metronidazole) and an X-ray. The X-
ray didn't show anything conclusive (possible thickening of the
stomach lining - subjective, according to the vet). The stools aren't
that soft, but they are pale, smelly and there is mucous on them. We
brought a fresh poop sample to the vet Friday night to test for
Giardia. Won't get the results until Tuesday or Wednesday. I suggested
a thyroid test, but they weren't able to do it because the cat was too
stressed from the X-ray. We'll have to go back to do that blood test.
Meanwhile, the cat isn't eating his new food (he ate a third of a cup
when he got home from the vet - had been fasting for over 12 hours for
his X-ray, so he was famished - but has not touched it since, so we
switched him back to his Innova and he's eating again). Apart from the
poop problem, the cat looks perfectly healthy. No change in appetite,
thirst (he might be drinking a bit more), weight, energy level or
daily routine. He is his usual gorgeous self. The only signs he has
are:

-light colored smelly stools
-mucous on stools
-pain upon defecating
-defecating outside his box (which he's probably doing because he
associates pain with the litter box, right?)

While we wait for the stool test results, we'll buy a new litter box.
We have been scooping it out at least once or twice daily. It's
clumping litter - same brand he's had since he was a kitten. Anything
else we can do? Does anyone have ideas on this? Questions we should be
asking the vet? Should we have his anal sacs checked again? Besides
the thyroid, is there anything else we should test? We have a toddler
and can't have the cat leaving presents everywhere in the house like
this. We need a speedy diagnosis! It's not just the hygiene question:
it's getting increasingly difficult to get the cat into his cage to
bring him to the vet.

Thanks in advance for any ideas.

P.S. I searched this newsgroup and a few of the relevant posts listed
links which are now outdated.