The Essential Cat Owner's Guide to Hyperthyroidism and Treatment Options

This is one of the most common diseases to affect middle-aged and elderly cats.

Is your furry friend losing weight despite a ravenous appetite? Are they jittery, with a coat that's lost its shine? They might be battling hyperthyroidism!

And because untreated hyperthyroidism in cats can lead to severe consequences like sudden blindness or heart failure, recognizing the early signs is crucial.

In this episode you'll learn how early detection and proper care can make all the difference. We'll unravel the 4 main options available when it comes to treating this disease, and how monitoring post treatment plays an important role.

💡Recognizing and treating hyperthyroidism early can ensure your feline friend enjoys a long, healthy life. By knowing the symptoms and treatment options, you can make informed decisions that best suit your cat’s needs 🐱

Find out more over in the full show notes at https://ourpetshealth.com/podcast/hyperthyroid-cat

Love the show? Sharing this episode or leaving a review helps others know it's worth a listen! - https://ourpetshealth.com/review

Transcript

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Hypothyroidism is one of the most common conditions of middle aged and elderly cats. The consequences of leaving it untreated or undiagnosed can be really severe but thankfully it is quite easy to pick up. There are some key signs and symptoms that you can look out for to know the early stages of hypothyroidism and there are numerous different treatment options available so you can be almost guaranteed to find one that works for you and your cat. Welcome to the call the vet show. The podcast that helps pet parents understand and optimize the health of their furry family so they can live the full and happy life you want for them. And here's your host, veterinarian doctor Alex Avery. Hello. Welcome back to another episode of the show. I'm veterinarian doctor Alex. And in this episode, I'm bringing you details about a condition that every cat owner needs to know about. It might be a condition of, older cats, kind of late middle aged senior cats, but it is that common that it could affect your cats. And the sooner you get onto it, the sooner we diagnose that problem, the sooner we start treatment, the sooner you recognize the often fairly classical telltale signs that your cat might be suffering from this condition, the sooner they can get the treatment they need and the less impact it can have on their life. The reality is that if it's successfully treated, if it's picked up soon enough, it's if it's treated successfully, then hypothyroidism need have no impact to your cat's life. So with that in mind, make sure you hit that subscribe button if you're not already following this podcast, just so that you don't miss out on any future episodes where I talk about all things to do with pet health. Some episodes are like this one where they're very targeted towards specific, conditions, specific treatment types, maybe even specific drugs, you know, really more niche topics, I guess, that people might be searching through to what I've been talking about more recently, which is actually the state of the veterinary industry, the state of pet health care, how the development may have not had the impact on health that we would have liked, and many wider topics in a similar vein. So I'm really pleased to be spending some time with you today and hopefully into the future as well. So let's jump in to the episode today. And now on with the show. And of course, the first thing to think about is actually what is hyperthyroidism. So hyperthyroidism is an overproduction of the body's thyroid hormone. Now the thyroid glands, they sit either side of the neck. There's 2 of them. Now why do we get an overproduction of the thyroid hormone? Thankfully, the most common reason is what we would call a benign growth. So a benign functional growth of thyroid tissue. And that basically means that it is a non cancerous growth. So it doesn't spread to other parts of the body and cause really nasty fatal cancer, but we get a growth of that gland that then produces more and more of this thyroid hormone. That is the normal state of affairs. There are rarer instances where we have a malignant tumor and that is a nasty tumor that is much harder to treat, but thankfully that is in the absolute minority. It's really not very common at all. And what the thyroid hormone does in the normal normal situation but also in hypothyroidism, it controls the body's metabolic rate which is kind of the rate at which all of the cells work effectively. So if you have got an overproduction of thyroid hormone, the body is working especially hard all the time. It is using a lot of energy. It is breaking down the body's reserves, which is why we'll see some of the symptoms that we are, but but this applies to all of the body's organ systems as well. So whereas in in dogs and in people, we get a hypothyroidism, and you might be familiar with that with a lack of production of thyroid hormone where we can get weight gain and lethargy and various problems like that. With cats, it's the opposite. And so the symptoms and signs that we'll see of a hyperthyroid cat typically are a cat who is always hungry but is losing weight no matter how much they eat. And that's because the body is just working so hard. It's breaking down all of the food, all of the energy as soon as it comes into the body. And the cat simply can't keep up with the the nutritional intake and the calorie intake that the food is providing. But we will also see other changes. We'll have a cat that will be anxious. They're going to be wired all the time and you'll see them maybe being unable to settle and they're they're jumpy and and their personality really changes. That body weight goes hand in hand with loss of muscle, so you'll often feel say along their backbone especially they'll become very bony. You'll see a change in their coat quality. So rather than a nice lustrous soft glossy coat, it will become quite dry and and and matted and knotty and they'll just look quite unkempt. We can also commonly see intestinal signs with with vomiting and diarrhea being pretty common as well. And then depending on your cat, they may start to experience other symptoms if other organ systems are affected. It can certainly cause problems with their heart. So you might notice some some lethargy. They don't have the the the normal get up and go or ability to exercise and play that they once had without becoming breathless. They might start drinking an awful lot more and peeing a lot more if the kidneys are becoming affected. Worse one of the worst case scenarios is that they might go suddenly blind because their blood pressure goes up and that causes what we call retinal detachment, which can cause very sudden blindness. And you've been unaware of a problem, and then all of a sudden your cat goes blind. Thankfully, not very common. And then before we jump into how to diagnose this problem and and the treatment options, it's worth also mentioning why cats develop hypothyroidism in the first place. And there has been many different suggestions over time. The bottom line is is that we don't know with a 100% certainty, but there's likely a few different factors, and those factors are likely to be genetics. Some cats are just genetically going to be more prone to developing hypothyroidism. And then the other big factor is going to be exposure to certain chemicals in the in their environment. It was felt that there was a issue with food and with some fish diets, but that's a thing of the past. With current kind of food practices, that's not going to be a problem. But one chemical that is felt to be an issue are fire retardants that are in furniture and in furnishings in the house. To some degree, there's no getting away from that, but they are felt to be a risk factor for the development of hypothyroidism in cats. So then how is hypothyroidism and overactive thyroid diagnosed in cats. So the typical presentation is a cat who is is hungry, but is losing weight, and then maybe they might have vomiting or diarrhea and these coat changes like I discussed. There's other conditions that can cause that. Diabetes is the other big one that springs to mind. That's typically a cat who was very fat and is then becoming quite skinny quite quickly. But they will be happy. They'll be eating a lot and losing weight. Thankfully, these cases are quite easy to diagnose because if I'm presented with a cat that fits this picture, they're the right age, they're kind of an older cat. The first thing I'm going to do is I'm actually going to feel their neck to see if I can feel their thyroid glands. Now in some cases, they're really big and you can almost see them, but actually most cases, it's a very subtle increase. So you, yourself, you're not going to be able to feel that because you're not used to feeling cat's necks on a daily basis. Now if I'm feeling an enlarged thyroid gland, my index of suspicion is going to be increased. We don't always feel it though. So the other things I'm going to be looking at when I'm examining an older cat who I'm suspicious of with hypothyroidism, I do this in every exam anyway, is actually listen to their heart. So I'm here, I'm listening to a couple of different things or I'm listening for a couple of different things. The first of those is what we would call a gallop rhythm and that's where rather than having the 2 beats of the heart there's actually an extra beat. Extra beat. And that can be a sign of a heart that is under stress, particularly because of hypothyroidism. It's it's not synonymous with that. There are other things that can cause that. But again, that increases my risk of suspicion. And it may also be that there is a a murmur to that heart as well, which again makes me wonder is there something going on with the heart. And if there is a problem with the heart, then what are the causes of that? Well, hypothyroidism in cats is certainly one big cord. Hi. It's doctor Alex from the future here, and I'm just editing this video, and I realized that I needed to talk about atypical hypothyroidism. So it's not very common, less than 10% of cats with this problem, but in these, the situation is the opposite where they their appetite will be reduced. They'll be anorexic even maybe not eating at all. They might also be quite lethargic. The other signs still apply and it's still likely that in these cats, your vet will be testing for the presence of hypothyroidism despite the signs not being typical. So the next step is going to be to to run a blood test. And there's a few different things that we're going to be checking, but the main thing when it comes to hypothyroidism is we can measure t 4, which is our thyroid hormone. It's a relatively simple test. It may be that your vet can run that actually in their clinic. It might be that they need to send that off to the external lab, but the results will be back, you know, a day or so later. So it's very very quick. And more often than not, that level is is higher than normal and that gives us our diagnosis of hypothyroidism. In some cases, there is a bit of a gray area and it comes back as inconclusive and there's couple of options here. The first option would be to retest a month or so later to see if it has increased and we can make that diagnosis. The other option might be to to run a free t four test or an f t four test, which is the active components that is actually working on the body cells. And if that is elevated, then that again can allow us to make that diagnosis of hypothyroidism. So I say there's going to be a few other things that your vet will ideally want to check, and and that's also going to be kidney function is a big one because the kidneys can really struggle with the consequences of an overactive thyroid. And if they are struggling, then clearly that's something that we need to know about. And there's going to be numerous other things that are checked just to make sure that there's no other issues that we need to be aware of with your cats so that we can recommend the best treatment option for them. So your vet's made the diagnosis of hypothyroidism and we need to then think about how we're going to treat that. Now thankfully, it is a very treatable disease and is potentially even curable as well with one of the options. But if we start with the oral medication route, there are a few different options here. So, traditionally, going back a few years, it was 1 a tablet twice a day or 1 and a half tablets or whatever it was, a tablet twice a day that you'd have to give your cat. Thankfully, there's now medication that's once a day because peeling our cats can be challenging, especially a hypothyroid is a hypothyroid cat who's a little bit anxious and and not keen on being handled. But there is a tablet that we can give once a day. The other option for cats who we can't give tablets to, and you're certainly not alone if that's your cat, is, transdermal gel. So that is a medication, a little gel that, you wipe on the inside of their ear. We do that because that's where there's no hair, and the medication actually gets absorbed across the skin into their bloodstream, and it does the job of reducing that level of thyroid hormone and treating the the hypothyroidism very successfully. It's important that you wear gloves because it will transmit across our skin as well. And generally, what we say is you alternate here. So you use one ear one day, the next day you use the other ear and and so on and so forth. It's very effective. Now when we're treating medically, we need to then monitor the response to that. So we will monitor that by repeating the the blood test for those t four levels and we'll adjust the dose accordingly. So some cats will need a higher dose, some will need a lower dose. By and large, we can determine the correct dose very quickly and then your cat will need to stay on that treatment for the rest of their life. If we take that medication away, the thyroid level is going to go up. That happens very quickly, so even missing a couple of doses that level can start to climb. But if we keep giving the medication, we're going to control that disease and treat it very, very successfully. Now if medication doesn't sound like the best option for your cat, there are 3 other treatment options available. The next one is a diet. So there is a special diet. It's called YD, and this is an iodine restricted diet. It is, produced by Hills, and it has been shown to successfully control hypothyroidism very well in those cats that eat this diet and nothing but this diet. And this is really important. So iodine is crucial for the production of thyroid hormone, but it actually doesn't need very much iodine to produce the thyroid hormones. So any other diets, any other food items are generally going to be much higher in iodine levels. So even getting a little bit of something else is going to make that diet useless. So this is going to be this diet is going to be appropriate in those cats who who eat the diet, and there's a period, you know, transitioning your cat onto a new diet takes 2 to 4 weeks, you know, maybe even longer if they're particularly fussy. Thankfully, with a hypothyroid cat, if we're starting treatment while they're in the the the throes of that disease, they tend to eat almost anything that gets put in front of them because they're so hungry. But they need to eat this diet and nothing but this diet. And so, really, they need to be in a one cat household. It becomes much more challenging if we're in a multi cat household. You know, if there's young children around and they're dropping food on the floor that your cat is then scavenging, that can upset their diet. So it's certainly not an option for everyone, but it's a really useful addition to the treatment options available in particular situations. Now the 3rd and 4th options are potentially curative, so they can involve, a single procedure that then removes the need for future treatment. Now the first of these is surgical removal of the thyroid gland. This is something that I guess we did a lot more, you know, historically because peeling a cat twice a day was very challenging and that was really the only other option. But we can remove the we can remove a thyroid gland if only one of them is affected, then great. We can remove that without really concern of of many complications at all over and above the normal risks with surgery. But the problem is is that cats have 2. And even if one is affected now, it's reasonably likely that the other thyroid gland is going to be affected at some point in the future. Clearly, some cats are going to be diagnosed and have both affected at the same time. If we're removing both thyroid glands, we can get a situation where we have hypothyroidism, so an underactive thyroid effectively to little thyroid hormone. And we need to actually then supplement with thyroid hormone, which is kind of counterproductive to everything that we're trying to achieve. And there's also something called parathyroid glands, which are little glands that sit next to the thyroid that are involved in in different functions with the body, but it can be very difficult to preserve them and so we can get other other complications. So I guess surgical removal of thyroid glands has by and large fallen, you know, fallen out of favor. That said, if it's felt that your cat has a more aggressive form of hypothyroidism, it might be that that's something that your vet discusses with you. And then the final treatment option is what we call iodine 131 treatment or radioactive iodine treatment. And here radioactive, that can be quite scary. But what happens here is that if you think back, I said iodine was very important for the production of thyroid hormone. This particular version of iodine, iodine 131 is radioactive, but that gets injected into your cat. It then gets concentrated in their thyroid gland, and that radioactivity actually kills the the excess thyroid cells that are present, and it effectively cures your cat of hypothyroidism. They it it it involves treatment in a specialist institution, so not all vet clinics have this by any stretch of the imagination. It can be quite difficult to access depending on where you are in the world, and your cat's going to need to stay in the hospital for for 1 or 2 weeks before they are discharged and effectively cured of their hypothyroidism. A few cats will need a second treatment or it won't work as well as expected, but, again, that's really in the absolute minority of cases. So how do you decide which is the best option for you? Well, it's going to come down to, you know, how easy your cat is to medicate, how that fits in with your lifestyle, you know, what's their what's your home environment like? Are they a one cat household where diet is going to be the better option? Costs are also an issue. Iodine therapy is significantly more expensive in the short term. But if we're thinking about medical therapy being for the rest of the life of your cat, now that might be 3, 4, 5, 6, 7 years depending on how old they are at the time of diagnosis. Those costs are going to be significant. The medication costs and the monitoring costs over time are going to be significant. So actually it is going to be cheaper to have that bigger outlay of the the radioactive iodine treatment to then remove any future cost that they might have in relation to that problem. So again, this is something to discuss with with your vets. It depends on the availability of that treatment in your parts of the world, and all of the associated costs involved. And then the final thing I want to say, and this is really important for cats that are being treated with hypothyroidism, is that as well as monitoring levels of that thyroid hormone and that's regardless of treatment to make sure that it's working or it has worked. We're checking kidney function in particular after treatment because what can happen is that the initial blood tests that are run to diagnose hypothyroidism might diagnose your cat with with concurrent kidney failure, which then needs to be managed. But even if that's normal, after we start treatment, what can happen is that an existing kidney failure can become unmasked. And what I mean by this is that it's present, but actually it doesn't show up in the initial blood test because the high blood pressure that is often the case of cats with hypothyroidism, it actually means that the changes that we normally see on blood testing in the presence of kidney failure aren't present. And so when we then treat the disease, when we reduce the level of thyroid hormone, blood pressure typically comes down, the kidney levels can go up, and we get a situation where we find that a cat has kidney failure. Now the big thing here is that it's not that the treatment has caused that cat's kidney disease, it's that the the treatment has allowed us to know whether or not your cat has kidney disease and it has revealed itself to us. The other condition that might become unmasked and is also very common in older cats and underappreciated and underdiagnosed is arthritis. So a cat with hypothyroidism, they they might move more freely. They they are anxious and and and they're not going to show the normal signs of arthritis. But it might be that once they are treated, once everything is settled down, you start to notice that they're having problems jumping up, that they are maybe not grooming themselves appropriately, that they're experiencing other symptoms that show that they are in pain. And again, it's not that the medication has caused that arthritis, it's that by treating the hypothyroidism, we are now aware that there is also arthritis present. And this all fits in with the fact that we're dealing with older cats who may have many different conditions. But, of course, hypothyroidism is not the only reason for a cat to lose weight. There are numerous other ones and I talk about them all in this video linked on screen. So if your cat's losing weight, you need to tap on that video to know all the different possibilities that could be going on. I'll see you there. And until the next time, I'm veterinarian doctor Alex. This is Our Pet's Health because they're family. Helping your pet live the happy, healthy life they deserve. Now just to close things off, if you did find this episode useful, if it helped you out, if you found it interesting, if you think it's something that other pet parents or the cat owners need to know about, I'd love it if you could share this on your social media or send it to a couple of your cat owning friends or family. Also, make sure you hit that follow or subscribe button on whatever app you're listening to this on. And then finally, if you'd love to leave me a review, it really does help more than you can imagine, helps me to spread the message to impact the lives of more pets and more pet parents no matter where they are in the world. You can head over to our pets health dot com slash review or leave a review on the podcast app. It really means more than you can imagine. And until the next time, I'm veterinarian doctor Alex. This is the Call the Vet Show because they're family. That's it for this episode of the Call the Vet Show. Be sure to visit call the vet dot org to join the conversation, access the show notes and discover our fantastic bonus content. We'll see you next time.