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Dr. B.
Dr. B., Board Certified Veterinarian
Category: Vet
Satisfied Customers: 22616
Experience:  General practice veterinary surgeon with extensive experience in a wide range of species.
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My cat is losing weight, rear legs are getting a bit weak and

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My cat is losing weight, rear legs are getting a bit weak and has a dull coat. Suspected worms at first so we treated him with drontal yesterday. He still has a good appetite but we are worried about him. He's about 11 years old. Any ideas?

Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.


I share your concern about Pepe's weight loss despite a great appetite.


Can you tell me how long he has been showing signs?


Any increase in his thirst or urination?


Any change to his stools?

Customer: replied 4 years ago.
We only noticed the weight loss in the last two weeks, don't know about his stools as he's got a favourite spot in the bushes.. No change in thirst noticed, he doesn't drink a great deal normally. His coat looks quite thin, not matted but poor quality, I can't normally see his skin through his fur but can recently. Today his unsteady rear legs worry me...

Thank you Jason,

First, I share your concern about what sounds to be quite dramatic weight loss for Pepe without an obvious source (ie dramatic appetite decline, or loss via severe vomiting or diarrhea). And if he is suffering from an internal issue that is causing a dramatic siphoning of nutrition from his normal body systems, then it is not uncommon to see loss of coat quality, loss of muscle mass, and even weakness.

The hair/coat situation is a sign that despite his great appetite, his body is struggling to meet its general maintenance nutrition requirements (therefore it is diverting nutrition for less critical systems like the hair/coat and likely redirecting these to more important organs). Furthermore, if his body is struggling for nutrition such that we are seeing this and weight loss, then it is not unexpected to see him feel weak or be also experiencing loss of muscle mass in places like his hips and back legs. With the muscle atrophy, this is essentially due to the body using its own resources to again support basic and critical life functions. So, these are all red flags that something is siphoning his body resources from him despite his great appetite.

With this in mind, we have to appreciate that this isn't an uncommon scenario in cats around his age. We can see older cats start struggle to keep weight on despite a good to great appetite for a range of reasons. Issues that can manifest this way at his age will include conditions like hyperthyroidism, diabetes, liver disease, and kidney troubles. As well, while it isn't nice to think about, we must keep in mind that cancer in cats his age can manifest as weight loss with little other signs (just as it doesn't impinge on the body, only to steal nutrients from him). As you noted, worms can also cause there signs but often dramatic weight loss due to worms is a feature of kittens and not commonly seen in adult cats.

To get to the bottom of what is going on it would be worth having Pepe checked by his vet this week (if he is due for a vaccination soon, you could move it up a wee bit early and have him checked out at that time). The vet will be able to have a feel of him and just make sure there are no sinister lumps and bumps to blame for his weight loss. And if you were able to bring in a urine sample at that point, the vet could check it for signs of diabetes (ie. sugar in the urine) as well as check its specific gravity (how concentrated it is) that can tell us if there are problems with his kidneys. Urine samples can often be collected by placing the cat in a carpet-less room with an empty (or with non-absorbable litter) litter box overnight.

If hyperthyroidism is a potential after your vet has examined him, then a blood sample may be checked to assess his thyroid hormone to determine how severely affected he may be. As well, if you do have a blood sample checked, you can also have his blood sugar, liver and kidney parameters checked at the same time, giving you a good chance of ruling out the above differentials and determining the cause of your wee one’s abnormal weight loss.

Overall, in his case it would be prudent to have him checked out and at least have a urine sample (or blood sample) checked. Because all of his signs tell us that one of these issues are lurking and stealing nutrition from him. And if you are able to the bottom of the exact cause sooner rather then later, it will give you the best chance to deal with it and help support him in a way to make him more comfortable and possible regain some weight.

I hope this information is helpful.

If you need any additional information, do not hesitate to ask!

All the best,

Dr. B.


If you have any other questions, please ask me – I’ll be happy to respond. Please remember to rate my service once you have all the information you need. Thank you and hope to see you again soon! : )

Customer: replied 4 years ago.
Thanks for a very informative response, as a heads up on my part what would your gut instinct be? Latter part of last year he suffered from flea issues, that we treated aggressively within the home and he started wearing a flea collar. Thought we were through that trauma, but couldn't that be a source of the worm issue. I suspect the Drontal medication could take a little time to do its work?

You are very welcome, Jason.

If a severe worm burden were to blame, then it can take a few days to weeks to see noticeable changes in his signs (since his body would need time to repair the "damage" from them). In regards XXXXX XXXXX gut feelings about Pepe, I have to say that not being able to examine him does make that a difficult call to make. Still if he hasn't had any change in thirst, then I'd like to put our concerns about his kidneys lower on our list. And if he is ravenously hungry (eating like a wee starving man), then I'd want to make sure this wasn't a hormonal issue like thyroid disease and possibly diabetes. Finally, with what sounds to be a fairly quick onset, I'd want to put cancer lower our list as well, but this would definitely be something that would require an examine to really rule out.

All the best,

Dr. B.


If you have any other questions, please ask me – I’ll be happy to respond. Please remember to rate my service once you have all the information you need. Thank you and hope to see you again soon! : )
Dr. B. and other Vet Specialists are ready to help you
Customer: replied 4 years ago.
Thank you so much for your helpful responses. I do hope he pulls through poor chap. i'll book him into the vets this week if I see no improvement soon. Take care and thanks again.
You are very welcome and thank you so much for your kind rating. It is very much appreciated! Even though you have rated our conversation, we can still communicate. So, if you have other questions regarding Pepe, please just click reply. I am always happy to help. And hopefully the vet will find something that can be treated to get some weight on poor wee Pepe.

Have a great day,
Dr. B.