Posting for a friend. Wondering if anyone has any suggestions as this pup is giving cause for concern. A heart murmer was diagnosed at 9 weeks but this has now disappeared, however puppy isn't growing normally, although playing and lively enough. Pup has been tested negative for worms but no other tests as yet. Weight loss has occured over the last week and a half but the puppy has always been on the small side.

I wondered whether it could be a liver shunt? Can anyone think of any possibilities it might be or what direction to take?
The puppy is still with the breeder.

I have heard of similar, a lady who thought her puppy had a liver shunt, diagnosed by the vet, at eight months he died, tiny and sickly. But she got a second opinion from another vet just before... it was due to an obstruction, not a shunt, and could have been sorted much earlier. So definitely see the vet and explore all the options. My own bitch had always been on the small side, at ten weeks old she was smaller than her litter mate. The vet said 'Is she actually eating...?', I knew she was and she grew up very healthy but they can be such a worry at such a young age.

How old is the pup?

Has the pup been vomiting occasionally? Had days of being lethargic? Those were the only 2 symptoms we had with my Mums dachsie till she became very ill on Xmas Day, she was 8 months old and had surgery 2 weeks after her becoming very ill, she was 9yrs old last month.

There is a blood test they can do to find out how the liver is functioning

I hope things improve and it isn't anything serious.

Is the pup eating well and more importantly what is it's output like.

I think blood tests for liver function etc.

If the pup has runs what about Giardia or Campylobacter.  As pup with the breeder I assume worming up to date?

My Roxy had giardia, campylobacter, and french heartworm.  She was diagnosed after full labs when she started to refuse to eat! Previous to that she had never been a great doer and always had a sensitive tummy but was not actually ill.  I would definitely look at those tests too if they have not been done

Can we ask what breed? Dwarfism is known in some breeds.

I would def take pup for tests, it could be a number of things and a blood test may throw some light - it could be kidney problems, is the pup eating normally? has pup been wormed properly throughout life so far?  It definitely needs investigating :-(

Thank you for all your replies. The puppy is acting/eating normally and tests have shown no worms. He's going to have some blood/urine tests done so hopefuly that will show if there is a problem.