First, I am glad to see that his gums are good and his breathing hasn’t changes. Though if he is a bit tender in his belly as well, this raises concerns of his anorexia being related to a possible severe bacterial or viral gastroenteritis, pancreatitis, or a possible ingestion of harmful items (ie toxins, plants, non-edible items). Though at his age, we’d hope that he’d be less inclined to eat odd items. Though at his age there is risk of possible anorexia secondary to metabolic or organ issues too. So, we need to tread with care.
In any case, since we are likely looking at a nausea induced anorexia that will be sapping his energy and leaving him as listless as reported, we need to start some supportive care and be proactive here. To start, since he sounds so collapsed and weak, we can try boosting his blood sugar by rubbing a sugary syrup (ie glucose syrup, honey, karo syrup, pancake syrup, or even non-grape jam) onto the gums. This will get some sugar into his and hopefully perk him up for us.
Following that, we can try to counter any nausea putting him off food with 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), Tagamet (More Info/Dose Here @ http://www.petplace.com/article/drug-library/library/over-the-counter/cimetidine-hcl-tagamet)]. Whichever you choose, we’d give this 20 minutes before offering 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.
Afterwards, we’d want to tempt with favorites or try a light/easily digestible diet like cooked white rice with boiled chicken, boiled white fish, or 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 GI. Though if he cannot be tempted and since he is so weak, we may need to carefully offer or syringe feed watered down Hill's A/D, Royal Canin Recovery, Nutrical paste, puppy food, Dogsure, 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.
Since dehydration is a risk if Teddy Bear won’t drink, we need to keep an eye on his hydration. To check this and make sure dehydration isn’t an issue, there are a few parameters you can test. Further to checking for gum moisture, you will want to make sure his eyes are not looking sunken and that he doesn’t have a "skin tent" when you lift the skin. To see how to check these, you can find a good video HERE (http://www.ehow.com/video_12232503_dog-dehydrated.html). If you do see any of these signs already, then that would be our cue to have him seen before this becomes an additional issue (especially since its often dehydration that makes them feel unwell). Otherwise, we’d want to potentially syringe fluids (ie water, Pedilayte) at a dose ~48ml per kilogram of his weight over each 24 hour period to help him at least keep up his intake and avoid dehydration. Of course, if he were to vomit, we’d have to stop.
Overall, a wide range of agents could trigger the signs we are seeing for wee Teddy Bear. This sound suspicious of an underlying nausea (especially with the lip licking) causing anorexia and one of those above concerns would be our top suspects. Therefore, we’d want to start supportive care to try to settle his stomach. Though if he cannot keep that or water down, appears dehydrated already, or doesn’t respond to the above within 12-24 hours; then we'd want to get his vet involved. They can assess his hydration, rule out fever, ensure nothing in his stomach that shouldn't be, or any sinister viruses present. Depending on their findings, his vet can treat with injectable anti-nausea medication, appetite stimulants +/- fluids and antibiotics to settle this and get him eating properly for us.
Please take care,
If you have any other questions, please ask me – I’ll be happy to respond. **Afterwards, I would be grateful if you would rate my service by clicking on the "Rate my Expert' button at the top of the page as this is the only way I am credited for helping you. Thank you for your feedback!: )