Malabsorption & severe weight loss

Question
Dear Dr. Joyce,
I am the owner of a 14 month old bitch, she has been suffering from loose motions consisting of semi -digested food for the last 4 months. As a result there has been severe weight loss. She has polyphagia and passes motions regularly about 2-3 hours after eating. All of her stool & blood tests were normal.... although now lately the blood values have started dropping below the normal limit gradually.
As per the vet's guidance, I have tried all kinds of medications on her ranging from metrogyl, to doxycyline, to enzymatic therapy, and now a drug called 'Hetrazan' containing Diethycarbamazine Citrate. Nothing has worked.
The eventual decision is to conduct a procedure to take a biopsy of her small intestine. This involves anesthesia and the surgeon does not want to take this risk as she is far too underweight.
Kindly advise.
Thank you.
Yashoda (from India)

Answer
I would like you to confirm whether she has been tested for Exocrine Pancreatic Insufficiency(EPI). This is a disease where the pancreas stops producing digestive enzymes and the food cannot be properly digested and hence nutrients cannot be absorbed. In a young dog this is the first thing I would suspect. Ask your vet if he has perfomed a TLI test. This is diagnostic for EPI. If you pup has EPI, the treatment is supplementation of pancreazyme and trypsinogen which, in the US, is a drug called VIOKASE or PROZYME. This medication must be used in powder form to be most effective. The drug is mixed with the food and allowed to sit for several minutes before feeding. Your pup may also have bacterial overgrowth of the intestine because of the chronic diarrhea. This can be treated with antibiotics such as metronidazole, tetracycline, tylosin, etc. She may also be deplete of vit B12 which should be supplemented in the short term by injection until she starts gaining weight. Lastly, these dogs benefit from a highly digestible diet. I am not sure what is available to you in India. In the US we use Eukanuba Low Residue or similar.
Please send follow-up questions.
Dr. G.