Hello & welcome. I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
Now Arthur's situation is not an uncommon one. Kittens tend to have naive immune systems (since they are babies) and the stress of adoption (ie new house, new people, away from their kitty family, etc) can affect the immune system and let opportunistic agents gain a foot hold and cause the signs you are seeing. And often the kitten appears otherwise normal and keen to play; until the diarrhea starts to cause dehydration (which is what tends to make them feel poorly).
Now when a kitten has soft feces that is progressing to watery diarrhea, we can see a number of causative agents. This includes bacteria, viruses (coronavirus, rotavirus, panleukopenia, etc), parasites (GI worms and the protozoa like coccidia, giardia and also cryptosporidia, tritrichomonas), nutritional sensitivities, stress, and toxins. Hopefully, since you have not mentioned him getting into any toxic chemicals, plants, or eating anything he should not have, the last differential will be less of an issue for him.
Just to note, we can see a bit of fresh blood with any diarrhea cause due to the abnormal feces irritating the colon on its way out. So, as long as its not profuse blood or hemorrhagic diarrhea, this tends to be a secondary sign that settles as we treat the diarrhea.
With all these concerns to consider, we need to rule each one out step by step. To start, if he hasn't been wormed in the past month, then you'd want to start with this. The reason why we are very keen to worm them when they show these signs is because gastrointestinal worms are the most common cause of diarrhea in the otherwise healthy stray. This gastrointestinal worm burden in kittens is most often directly from their mum (since the worms capitalize on her drop in immune system strength during the stress of birth to spread through her feces to her kittens). Therefore, if he was a stray and hasn't been wormed, the this is a big red flag we need to address here. Ideally at his age, this should be done monthly (and every 3 months once they are over 6months of age). Ideally, you want to use a good quality broad spectrum. To treat worms, you can buy worming products over the counter. Therefore, you can ask for them at the vet's or at your local pet stores and these will be dispensed to you. There are a range on the market, but you want to use a good quality wormer that covers both round worms and tapeworms. In this situation, it would be ideal for you to treat Arthur with Panacur, Drontal, or Milbemax as it will cover all the worms in question. Do make sure to have an idea of his weight before purchase wormer to make sure you get the correct dose for his size.
If he is a cat who is touch to tablet (though the Panacur does also come in liquid or granules to be mixed with food + the Milbemax is a palatable tablet), there are also spot-on options. These include Advocate, which will cover all the GI worms. It doesn't cover tapeworms (since you can only put so many drugs into one product) but if we needed to treat for tapeworms, Drontal also has a spot on formulation for treating those.
Now you didn't mention his diet or if he was gradually weaned over to a new one (since quick change can cause diarrhea), still in cases like these we do tend to want to put these wee ones on a light/easily digestible diet. Examples of this would be boiled chicken, 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 in cases like Hill’s I/D or Royal Canin’s sensitivity. These diets will be easier for his compromised gut to digest and this will ensure more nutrition is absorbed and not just lost to diarrhea. Furthermore, feeding these in small, frequent meals (instead of a few big ones), will further aid the GI in digesting what he eats which will leave less material in the gut to be part of the diarrhea.
On top off all of this, you do need to keep an eye on his water intake and hydration status. Since he is young and won't have the body reserves as an adult, we can see dehydration arise quickly with diarrhea in kittens. If possible, you do want to check his hydration now. To check this and make sure he is not becoming dehydrated there are a few things we can test at home. One is whether the eyes appear sunken, if the gums are tacky instead of wet/moist, and whether he 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 principles are exactly the same) If you are seeing any signs of dehydration already, then you do want to have your kitty seen by the vet before this gets any further out of control.
In regards XXXXX XXXXX you can do to help stave off dehydration at home (though do note that if he is already then he will likely need more the oral rehydration), encourage him to drink but 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. If he isn't amenable to drinking, you may wish to offer unflavored pedialyte via syringe feeding. While we cannot do this if they are vomiting, it may be an option for this situation. A typical maintenance rate for hydration in an animal 48mls per kilogram of her body weight a day. And since he has diarrhea, we tend to add an equivalent volume to what is lost in diarrhea to this total for they daily intake goal. If you do give syringe pedialyte, this should obviously be divided up into multiple offerings through the day rather then all at once. This value will give you the total he needs for the day and is a good starting point to give you an idea of the feline daily requirement. If he does vomit if you give pedialyte, I would discontinue this as a therapy. (since we don’t want vomiting because of our intervention).
If you worm him, try a bland diet but the signs don't settle down, then we'd need to consider involving the vet to rule out those other causes for this chronic diarrhea presentation. And if you do have to go down that route, then a fresh fecal sample can be key to helping you determine the underlying cause for his diarrhea. Ideally, we'd want to have the sample sent to the lab for examination and culture. The lab will be able to rule out parasites, protozoa (especially tritrichomonas as it can cause diarrhea that just runs out of them), test for viruses and culture the feces for pathogenic bacteria. This enables us to isolate the causative agent and use targeted treatment to clear it for him.
Overall, in Arthur's case, it sounds like we have an opportunistic agent that causing his diarrhea and that this diarrhea is getting to a point where the colon is becoming irritated and inflammed. Therefore, you do want to settle this as quickly as possible for him. To do so, you want to take a step by step approach to start ruling out some of the above causes. Therefore, I'd strongly advise worming and an easily digestible diet. If you do this and don't see the signs settling within a 12-24 hours (since he will have only little body reserve and we don't want this to linger over the weekend), then consider having your vet examine him at that stage and have them send off a fecal sample. This will allow you to pinpoint the cause of the diarrhea, and the vet will be able to cover him with antibiotics and cat safe anti-diarrheal medications to settle this for him and get his feces back to normal..
I hope this information is helpful.
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All the best,
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