Thank you for the additional information on Gremlin.
As I noted before, for his signs to be so severe that he is completely off his food/water and is suffering weight loss already, we do really have to be concerned here and act quickly.
The reason we want to manage this pro-actively is because cats were not well designed for the anorexic lifestyle. When they are off their food for extended periods of time, body fat is broken down and released into the blood stream, causing their liver distress (ie. hepatic lipidosis) that can make getting them better even more difficult for us. So, it is imperative for us to determine what is causing his signs and address it as quickly as possible to get him back on track and back to feeling like himself.
Now when kitties start vomiting there can be a number of culprits. This includes bacterial infection, viruses, parasites, pancreatitis, dietary indiscretion, sensitive stomachs, toxins and foreign bodies. Since he is a young lad, we do always have to be extra concerned about the potential that they can get into toxins or may have ingested a non-edible object (ie ribbons, trash, hair ties, toys, etc) that could get stuck in his GI.
Since you had noted that he has abdominal pain when handling, I do want to note that there are two differentials that spring to the top of our list with this sign being present. These are pancreatitis (a condition known to be very painful and this is an organ which just happens to be located just at the junction of where the ribs end and abdomen begin) and GI obstruction with a foreign body. Both conditions often cause severe nausea/vomiting, anorexia and abdominal pain. So, while we do still have a range of potential causes to consider, these would be the ones I would be most concerned about with Gremlin.
And in that case, it would be ideal to have him checked by his vet (as long as he is comfortable just now you can wait until his regular vet is open rather then rushing him to a ER vet). The vet would be able to have a feel of abdomen and determine if there is anything lodged in his GI or whether then pain can be localized to an inflamed pancreas. Depending on their findings, they will be able to advise you to whether this is a situation where they need to go in surgically to remove something he has ingested (hopefully not the case) or if medical management is indicated here. If a foreign body is ruled out and pancreatitis is confirmed, then this often can be managed with pain relief, antibiotics, anti-vomiting medication by injection +/- IV fluids (depending on severity of signs and response to initial medical treatment).
In regards XXXXX XXXXX you can do at home in the meantime to try and give him some relief from the severe vomiting and nausea (which is the likely reason he wont' eat/drink, since kitties avoid the risk of vomiting by going off their food), you can try to him with an antacid. There are a number of antacids that are available over the counter and pet friendly. I would advise only treating with one, but the two I tend to recommend are Pepcid (LINK) or Zantac (LINK). This medication of course shouldn’t be given without consulting your vet if she does have any pre-existing conditions or is on any other medications. Ideally, it should be given about 30 minutes before food to ease his nausea.
As well, you will want continue to try and see if you can get him eating (ideally once the antacid settles his stomach). Favourite foods are allowed as you have but also consider tempting with a light/easily digestible diet. Examples of this would be boiled chicken, boiled white fish, scrambled eggs (made with water and not milk), meat baby food (do avoid the ones with garlic powder in the ingredients) or there are also veterinary prescription diets that can be used here (ie Hill’s I/D or Royal Canin’s sensitivity.) Offer this as small frequent meals (1 tbsp at a time with 30 minute breaks in between to discourage vomiting). If you try this and he isn't keen to eat, then I'd not press him on it tonight (since we'd want an empty stomach when he sees his vet in case they did have to operate to remove a foreign body).
Now with him being so young, dehydration is a major concern here. Vomiting can quickly dehydrate a young cat, so we need to keep an eye on his hydration. To check his hydration status to make sure he is not becoming dehydrated there are a few things we can test. One is whether the eyes appear sunken, if the gums are tacky instead of wet/moist, and whether the pet has a "skin tent" when you lift the skin. To see how to check these parameters for dehydration, you can find a wee video on this HERE. (They use a big dog but it makes it easier to see and the principle is just the same). If you are seeing any signs of dehydration already, then this would be another red flag telling us that he should see his vet first thing in the morning.
Since he is vomiting, we are limited in what we can do via oral rehydration at this stage. That said, if he has kept down the fluids you have offered that is a good thing and may allow us to further support him and fight dehydration. Now if the antacid can settle the vomiting, then you can again try an encourage him to drink by offering fresh water or even low-sodium chicken broth. As well, wet foods (as mentioned above) are 35% water, so getting him to eat will help us deal with water intake as well. Further to that, there is the syringing of fluids. Ideally, we'd want to use an unflavored electrolyte solution (ie Pedialyte) since this will replenish the electrolytes he is losing in his vomit. In regards XXXXX XXXXX of fluids that we'd want to be administering, a kitty daily requirement is 48mls per kilogram of his body weight. This won't cover his vomiting losses (though you can quantify the volume vomited and add it to the total volume) but is a good place to start with trying to keep him hydrated. Of course, you need to do this with caution since we don't want him to end up vomiting because of our intervention.
Overall, there are a range of conditions that can cause vomiting in cats Gremlin's age. In this situation, with the weight loss and potential length of anorexia, we do need to be proactive. Therefore, you can try the above supportive care tonight but consider seeing the vet first thing tomorrow. The vet will be able to have a feel of his belly and make sure he hasn't eaten something he shouldn't have, and determine the underlying cause for his vomiting. As well, the vet will be able to cover him with antibiotics against bacterial gastroenteritis and anti-vomiting medications by injection to help settle his stomach and get him back on track as quick as possible.
And just in case you feel he is deteriorating over tonight and you do want him seen sooner by an emergency vet, you can find one local to you, HERE and @ http://www.vetlocator.com/.
I hope this information is helpful.
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All the best,
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