I have not heard back from you, but since your lass is quite young and this is a worrying situation, I do want to leave my thoughts for your return.
First, we need to tread with care if she is vomiting this profusely and too nauseous to even drink. This is because vomiting kittens are high risk of dehydration, weakness, and blood sugar crashes if their signs are left to linger. So, we need to be proactive and aggressive in our care to get her settled as quickly as possible.
Now just to note, potential causes for severe upper GI upset in a cat her age would include bacterial or viral gastroenteritis, pancreatitis, parasites/protozoa infections, general dietary indiscretions, and ingestion of harmful items (ie toxins, plants, non-edible items).
As long as the last one is unlikely, we can consider trying to soothe her stomach. Though I do have to warn you that if she is severely nauseous, we may need to have her local vet start her on injectable anti-vomiting medication to just break this vomiting cycle. Otherwise, if she hasn’t just vomited, you can consider trying an OTC pet safe antacid like Pepcid (More Info/Dose @http://www.petplace.com/article/drug-library/library/over-the-counter/famotidine-pepcid) or 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 check with her vet before use if she has any known health issues or is on any medications you didn’t mention. Though again if she cannot keep this down, then we’d want her vet to bypass her mouth with injectable anti-vomiting medication.
While we are waiting for that to take effect or if she appears weak/lethargic already, I’d note that we may need to try to boost her blood sugar. To do so, you can try 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 her and hopefully perk her up for us.
Otherwise, once that has had time to absorb and she is steadier on her stomach, you can consider starting her on a light/easily digestible diet. Start with a small volume (a spoonful). Examples you can use are boiled chicken, boiled white fish, scrambled eggs, or meat baby food (as long as its garlic/onion free). There are also OTC vet diets that can be used (ie Hill’s I/D or Royal Canin’s sensitivity) too. When you offer that spoonful, give her 30 minutes to settle. If she keeps the food down, you can give a bit more and so on. As her stomach stabilizes, you can offer more. The aim of these diets is that they will be better tolerated/absorbed by the compromised gut. (It should also help if she has had mild fecal issues upsetting the colon to cause the blood you noted). Therefore, it should get more nutrients in and result in less GI upset. As long as improvement is being seen, I usually advise that the diet be continued until her signs are settled, and that they are then slowly weaned back to their normal diet.
Since dehydration is a risk here, we need to keep an eye on her hydration. To check this and ensure she’s not becoming dehydrated, there are a few things you can test. Further to checking for gum moisture, you will want to make sure her eyes are not looking sunken and that she doesn’t have a "skin tent" when you lift the skin. To see how to check these parameters for dehydration, you can find a good video HERE (http://www.ehow.com/video_12232503_dog-dehydrated.html). If you are seeing any signs of dehydration already, then that would be our cue to have her seen before this becomes an additional issue for her (especially as it is often dehydration that makes them feel unwell).
Overall, a wide range of agents could trigger severe nausea and its associated signs here. Therefore, as this is a risk situation for her, we’d want to tread with care. You can start supportive care to settle her stomach; but if she cannot keep that or water down, appears dehydrated already, or doesn’t respond to the above within a few hours (since she is quite young and this is quite profuse); then we'd want to get her vet involved. They can assess her hydration, rule out fever, make sure there is nothing in her stomach that shouldn't be there or any sinister viruses present. Depending on their findings, her vet can treat her with injectable anti-vomiting medication, fluids, +/- antibiotics to settle her stomach, and get her back feeling like herself.
Please take care,
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