Now I am glad to see that Doomsday hasn't those more severe signs I asked about. Though if he was managing with a lack of teeth before then that tells us that his mouth isn't likely causing the appetite loss we have here. Instead, his signs do support a suspect gastrointestinal issue with underlying nausea. And while its good he has responded to the treatments before, his relapses tell us that they were only symptomatic and not curing the root cause. Just to note, we'd be specifically worried about a chronic bacterial or viral gastroenteritis, helicobacter gastritis, chronic low grade pancreatitis (something I'm especially suspecting here), stomach ulceration, parasites/protozoa, or at his age we'd also have systemic concerns (secondary to kidney or liver disease, metabolic issues, IBD or even cancer).
Now if Sucralfate (a gastroprotectant) wasn't enough to soothe his signs, I'd suggest trying him at least on an OTC pet safe antacid [ie Pepcid (More Info/Dose @http://www.petplace.com/article/drug-library/library/over-the-counter/famotidine-pepcid), Zantac (More Info/Dose @ http://www.petplace.com/article/drug-library/library/over-the-counter/ranitidine-hcl-zantac)]. Whichever you choose, give it 20 minutes before food to allow absorption. Of course, do double check with your vet if he has a known health issues or is on any medications you haven't mentioned. Otherwise you could speak to his vet about a strong anti-nausea medication (ie Zofran, Cerenia, Metoclopramide) to just keep his nausea under control and with it keep him as sign free as we can.
As well, just since his appetite is declining (though treating with the above would hopefully stop that), we can try an easily digestible diet like cooked white rice with boiled chicken, boiled white fish, scrambled eggs, or meat baby food (garlic/onion free only) The aim of these diets is that they will be better tolerated/absorbed by the compromised gut. Though if he is struggling, then we can offer or syringe feed watered down canned puppy food, Hill's A/D, Royal Canin Recovery, or Clinicare Canine/Feline Liquid Diet. All of these are critical care diets that are calorically dense, so a little goes a long way nutrition-wise. So, you don't have to get as much in to meet his daily needs.
Overall, his signs do raise a few concerns for us and given the relapsing at his age this raises worries of an underlying cause like those I noted being at the heart of this. So, ideally we'd want to be thinking about blood work +/- an ultrasound to start narrowing this down. But in the meantime we need to better address this nausea he is suggesting with his behaviors to see if we can get him more settled and eating properly for us.
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