I share your concern about Cuddles. The withdrawing and hiding are very common signs of a cat feeling unwell, stressed, and vulnerable. As a prey species, cats that cannot pretend they feel well (since letting the world know you are unwell would make you a target for predation) will often hide as she is. Now what concerns me even more then that is the agitation and grunting. I know that she stresses going to the vet, but those signs do make me worried that she may have pain here. And if she does, it is better stress of seeing the vet then sitting there allowing herself to waste away while in pain. So, we can consider some supportive care to address general belly ache (since often nausea is what puts them off their food), but if she doesn't settle or continues to grunt then we'd need to think about either having her seen at her vets or requesting that her vet come to her (as all vets in the UK are obligated to offer home visits ).
Now when a older cat goes off their food, it is a vague clinical signs that can occur with a range of issues. If we are able to remove oral differentials (since there has been no drooling or noted struggling to eat before this) then we can turn our attentions to the conditions that would cause nausea (again most common trigger for appetite loss in the cat). When doing so, we do need to consider GI issues but also ones that affect the body on the whole. Therefore, we would need to consider grumbling bacterial infection, viral disease, metabolic conditions (ie hyperthyroidism, diabetes), cancer (ie lymphoma), organ disease (ie liver or kidney troubles) toxin and/or foreign material ingestion (the last two hopefully less likely at her age but a worry if she is sore).
To complicate matters, we get very concerned for cats who go off their food (and this is getting as worrying as you are concerned it is) because cats were not well designed for the anorexic lifestyle. When they are off their food, 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.
Now if Cuddles is turning away from food and drinking poorly, then it her signs likely include nausea despite not showing any vomiting (often nauseous cats go off their food rather then eat/vomit like a dog would). To rule out nausea as an anorexia differential, you can try her on antacid therapy. There are a number of antacids that are available over the counter and pet friendly. I would advise only treating with one, but the ones I tend to recommend are Pepcid (More Info/Dose Here ), Tagamet (More Info/Dose Here), or Zantac (More Info/Dose Here). 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 her upset stomach.
Once that is on board, you will want to try and see if you can get her eating (as I am sure you have been). Favourite foods are allowed or you can tempt her with 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 here (ie Hill’s I/D or Royal Canin’s sensitivity.)
Further to this, if she has been off her food this long and if tempting doesn’t work, then we do have to consider initiating syringe feeds to get food into her. In that case, you may want to try Hill's A/D (LINK) or Royal Canin Recovery (LINK) from your local vet. These are critical care diets that is comes as a soft, palatable pate. Both are calorically dense, so a little goes a long way nutrition-wise and this could just help get some more calories into her even if we can’t get a huge volume of food in. As well, for syringing food, you can use the animal version of Ensure (balanced for animals dietary requirements) called Clinicare Canine/Feline Liquid Diet (LINK). It is actually by the same people who make Ensure, but is formulated to meet out pet's dietary needs. Your vet should be able to order it for you but it is available without a prescription. They also make one specifically for older cats with kidney troubles, and this could be an alternative for an older cat. This way it would a means of getting food, staving off hepatic lipidosis, and buying you time to uncover the reason for her anorexia and discomfort.
On top off all of this, you do need to keep an eye on her water intake and hydration. To check her hydration status to make sure she 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 she 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 her vet before this gets out of control for her.
In regards ***** ***** you can do to help stave off dehydration at home (though do note that if she is already then she will likely need more the oral rehydration), encourage her to drink but offering fresh water or even low-sodium chicken broth. As well, wet foods (as mentioned above) are 35% water, so getting her to eat will help us deal with water intake as well. If she isn't amenable to drinking, you may wish to offer unflavoured pedialyte via syringe feeding. While we cannot do this if they are vomiting, it may be an option for this situation as long as we can keep that stomach settled. A typical maintenance rate for hydration in an animal 48mls per kilogram of her body weight a day. 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 she needs for the day and is a good starting point to give you an idea of her daily requirement. If she does vomits if you give pedialyte, I would discontinue this as a therapy. (since we don’t want her vomiting because of our intervention).
Overall, when a cat is anorexic as Cuddles is, it can mean a wide range of underlying issues. Therefore, we need to get her out from under the bed and examine those parameters I asked about. If she is painful or uncomfortable with you press on her belly; then you will want to phone her vet to have them come to her. Otherwise, as long as those checks you make are normal (so comfy belly, pink gums, breathing at a rate <30 breaths per minute), then start the above with her. Of course, if you do so but do not see improvement in 12-24 hours or she worsens (vomits, etc), then we'd again be best to have her checked. If you do get her vet out to her, they can assess her hydration, check her signs of any sinister lumps/bumps, any blockages, or internal issues. They can also cover her with antibiotics, anti-nausea/vomiting medication by injection and even appetite stimulating drugs if necessary. Depending on the findings, the vet will be able advise you on what is likely our culprit and what can be done to help your wee one before she just fades away on us.
To find a vet local to you that can come out to see Cuddles, you can check the RCVS Register (HERE).
I hope this information is helpful.
If you need any additional information, do not hesitate to ask!
All the best,