unusual behavior, urinating

Question
I have a small mixed breed dog, 30 lb, who is around 10 years old. We found him 10 years ago and he was 3 months old estimated by my vet then.  My problem is that just within the last 4 days he has been urinating in the house at night and getting me up to go out after he has done this.  He is tracking spots all over the floor like he just can't hold it.  Last night he woke me up and had actually pooped and vomited on the floor.  He was very anxious to go out even after this. I slept by him the rest of the evening to make sure he was okay.  This morning he pooped and I had to clean blood off his behind when he came back in.  No blood in the poop last night though, but mucus-like.  Just recently I had rescued a dog from the highway and kept him for four days waiting for a possible owner to claim him but ended up taking him to the Humane Society.  That evening is when the peeing on the floor started so I thought it may be spite.  Also, we just bought a new bed which is a little higher than the old one, and I fear he may have hurt himself jumping off but does not appear outwardly to be hurt. The bed came the day after the peeing started.  He has never in done this in the ten years that we have had him and has always been able to last all night.  He is also very thirsty.  Could some of this be related to diabetes or kidney problems? I am taking him to the vet today but I am intersted in your opinion as well.  I have been feeding him turkey and rice lately with a few flax seeds thrown in.  Is that a bad idea?  Thank you.

Answer
Apologies for the delayed response as I have been fighting off the flu.

Older dogs due have various reasons to have urinary incontinence.  Increased drinking and perhaps increased urination (may be the reason for the "accidents") can be seen with kidney problems, Diabetes, endocrine disorders and even some neurological problems.

The blood in the stool also could have several causes such as parasites, cancer, inflammatory GI diseases and infection.  Since you recently had a dog of unknown health history staying with you I would worry of the possible exposure of viruses or parasites.  It is good that you are taking him in to your veterinarian as it would be best to have some bloodwork, urine and fecal testing done as well as a full examination.

The diet should not be a problem at all.

Best of luck to you and your canine companion.