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As a pet parent, the thought of your cat dying is horrible.
Thyroid disease, also known as hyperthyroidism, is one common illness that must be caught early on or can become fatal. Unfortunately, the early signs of hyperthyroidism are often overlooked and might go unnoticed.
So, what are the signs your cat is dying of thyroid disease? The main things to look out for are substantial weight loss, vomiting and diarrhea, incontinence, cardiac issues, and seizures. At this stage, euthanasia is likely your best option, but this does depend on your cat’s age and comorbidities.
In this article, I explain what thyroid disease is so that you can identify the early signs of the disease that are often missed. I also cover the main signs that your kitty’s condition has deteriorated and become fatal, its prognosis, and when it is time to euthanize.
What is Thyroid Disease in Cats?
Thyroid disease is a common endocrine condition in older cats, affecting roughly 10% of felines over the age of ten. Thankfully, the disease is treatable if caught early enough, with many cats making a full recovery.
Hyperthyroidism is caused by an overactive thyroid gland. Every cat has two thyroid glands in its neck, which help control its metabolism. When these glands become enlarged and overactive, an excess of the thyroid hormones T3 and T4 are produced, leading to symptoms such as weight loss and hyperactivity.
In 97% of cases, this occurs because of harmless swellings in the thyroid. However, in rare cases, the overactivity of the glands can be due to cancerous growth. This latter situation has a less favorable prognosis, depending on the stage of cancer when it is discovered.
What Are the Signs of Hyperthyroidism in Cats?
When it comes to hyperthyroidism, an early diagnosis could be the difference between life and death for your feline. Unfortunately, the disease’s symptoms can vary and often don’t become prominent until the condition has progressed.
If your cat sounds congested when breathing, it is probably a sign that its thyroid glands are obstructing the airways. This is rarely a sign of hyperthyroidism but should be taken seriously if it does start to occur.
Some of the more common signs of hyperthyroidism in cats include:
- Increased thirst and urination
- Increased appetite
- Rapid weight loss
- Vomiting and/or diarrhea
- Increased energy
- Behavioral changes and/or anxiety
- Rapid heart rate
- Poor coat condition, e.g., hair loss, matted cat fur, or skin rash
- Thick, fragile claws
As you can see, many of these symptoms may initially be seen as a “positive” change in your cat. For example, if your cat is suddenly so hyper that it seems it has reverted to “kitten-like behavior” or is experiencing weight loss. If I notice my cat running around like a maniac, it can be easy to see it as a sign that she’s healthy rather than one of ill health.
When combined with the fact that the signs of hyperthyroidism can be late to develop, this means the condition is sometimes overlooked to the point that it is irreversible.
Is Hyperthyroidism Fatal in Cats?
As I’ve briefly covered, hyperthyroidism is entirely treatable if caught early. Several management and treatment strategies can help your kitty make a full recovery. The most common ways of treating this disease are surgical removal of the thyroid glands or medication that slows down the production of T3 and T4, such as methimazole. A low iodine diet or radioactive iodine treatment can also be used.
Unfortunately, the early signs of hyperthyroidism are often overlooked, meaning the disease can become irreversible. If untreated, it may cause serious heart problems because of the extra work your cat’s heart needs to do to match its overactive metabolism. It can also speed up the progression of kidney disease and cause seizures.
These difficulties are severe and would likely be fatal to your cat. As such, it is imperative that you take your cat to the vet at the first sign of hyperthyroidism. If your kitty doesn’t show any signs of the disease but you are concerned, I would still get them checked out just to be safe.
Signs Your Cat is Dying from Hyperthyroidism
When it isn’t caught early, thyroid disease can lead to severe complications, such as heart disease, kidney damage, and seizures. These will likely be fatal to your kitty, so it is vital that you understand the signs that could indicate your cat is seriously ill.
Below I have gone over the most common signs that your cat is dying from hyperthyroidism. If you see any of these signs in your feline, immediately take them to your vet. The symptom could have a different underlying cause, but I always think it is better to be safe than sorry.
1. Substantial Weight Loss
First up, we have weight loss. This is a common symptom of hyperthyroidism that is seen even in the early stages of the disease. However, when this weight loss becomes substantial, it indicates your feline is dying.
Because hyperthyroidism speeds up your cat’s metabolism, it will cause your feline to lose weight even when eating more than usual. So, if your cat is always begging for food, this may be why. The weight loss usually starts along your cat’s spine, but a dying cat will show severe muscle atrophy, starvation, and emaciation.
2. Frequent Diarrhea
The excess T3 and T4 hormones your feline produce speed up digestion. This can lead to your cat having frequent diarrhea, even when not eating much. Diarrhea occurs in roughly one-third of cats suffering from hyperthyroidism, so this is a good sign to look out for if you think your kitty is ill.
The increased amount of fluid lost during diarrhea can also lead to your feline becoming dehydrated, and they will have to compensate for the lost fluid in other ways. If your cat starts to drink a lot of water, this may be the reason why. If their fluid levels are not replenished, their body will begin to shut down its essential processes, and your cat may pass away.
Another sign that your cat is dying of hyperthyroidism is vomiting. Once again, this is caused by the unusual level of thyroid hormones being produced and can occur even if your feline isn’t eating much.
The increased production of T3 and T4 can cause vomiting in two ways: (1) by activating the chemoreceptor trigger zone in the brain and (2) by causing gastric stasis (the delayed emptying of the stomach). Unfortunately, vomiting can also worsen your feline’s weight loss due to its inability to keep food or drink down for an extended period.
4. Urinary Incontinence
Urinary incontinence is another indicator that your feline is seriously ill. In this case, the high thyroid hormone levels impact the kidneys, meaning your cat produces more urine. Kidney disease is irreversible and fatal, so this increased urination is a sure sign that your cat is reaching the end of its life. If I ever notice my cat peeing everywhere all of a sudden, I make sure to go to the vet.
Although you can do nothing to get the kidneys functioning optimally again, you can make it easier to deal with bathroom accidents. If you want to stop your cat from peeing on clothes and furniture instead of in its litter box, I recommend you clean the litter box more regularly and provide your feline with a box they can easily access.
5. Cardiovascular Symptoms
As I’ve previously covered, heart disease is a common complication of hyperthyroidism. When thyroid disease s left untreated, your feline’s heart has to work harder than usual to keep up with your cat’s new metabolic rate. This is what causes a rapid heart rate and high blood pressure.
Unfortunately, these can damage some of your cat’s organs, including the eyes, kidneys, and brain. They can also cause heart pain, so don’t be surprised if your cat has become so aggressive; it is one of the ways that cats deal with their pain. Any signs of cardiac issues, such as an increased heart rate or high blood pressure, can indicate that your cat is dying.
6. Seizures or Collapse
The final sign that your kitty is dying of hyperthyroidism is if they suddenly have a seizure or collapse. Overactive thyroid glands increase the amount of oxygen and glucose the brain needs. When this demand isn’t met, your cat’s brain starves, leading to a seizure.
This is terrifying for a cat mom to see, and I know how hard it is to stay calm, but you must keep a clear head. Your cat must get to the vet as soon as possible. If your feline is in the middle of a seizure, only touch it if it is at risk of serious injury, as you’ll likely be bitten or scratched in the process.
How Long Can a Cat Live with Thyroid Disease?
Many cats treated in the early stages of thyroid disease make a full recovery. For this to happen, your feline needs to either undergo surgery so that its thyroid glands are removed or have radioactive iodine treatment, which can be used to destroy the thyroid glands without surgery.
At a certain point, however, hyperthyroidism can only be managed rather than cured. If your cat’s condition is caught later on, it will live for roughly three to five years following its diagnosis, although this varies depending on the stage of the disease.
Your cat may be prescribed medication or on a low-iodine diet to manage the symptoms. Both options slow down the overactive thyroid and must be continued for the rest of your cat’s life. However, your kitty will slowly deteriorate, and the condition will eventually affect other areas of the body.
When to Euthanize a Cat with Hyperthyroidism
Whether or not to euthanize a cat is one of the hardest decisions a pet owner ever has to make. I had to make the call a few years ago when one of my cats had cancer, and it really was a heartbreaking decision that I will never forget.
If you are currently faced with this decision, I feel for you. Euthanizing your cat is not a simple choice, so I would definitely talk to your vet. They can go through each of the following factors with you to make sure you are doing the best thing for your furry friend.
1. How Your Cat Feels
Is your cat responding well to its treatment? Does it still seem reasonably healthy and comfortable in day-to-day life? If so, you may want to hold off on euthanasia for a bit longer. Your feline may be ill, but its quality of life isn’t affected too much.
However, if your cat has lost a lot of weight, seems to be in pain, or is generally declining in health, it may be the kinder option to put them down.
2. The Stage of The Disease
When discussing the option of euthanizing your cat, your vet will always consider the stage of the disease it is currently in. An earlier stage usually responds well to treatment and may even be able to be completely cured!
If your feline is in a late stage, though, it is likely already showing some of the fatal signs I mentioned above. At this point, there isn’t much that can be done for your cat, and it may be best to put it out of its misery.
3. Your Cat’s Age
Next up, we have your cat’s age. Although hyperthyroidism is more common in older felines, it can also affect younger cats. The younger your cat is, the higher the chance it has of recovery.
For example, if I had two cats in the later stage of thyroid disease, the younger of the two would have a much better quality of life compared to the senior cat. This means the need for euthanasia is less likely for a younger kitty.
Last but not least, I need to go over comorbidities. Treating hyperthyroidism becomes much more challenging when your feline also suffers from another condition, such as heart disease or kidney disease. Unfortunately, these conditions will likely develop if hyperthyroidism isn’t treated early.
Because the chances of properly treating your cat reduce when it has comorbidity, euthanasia can be the kindest option. It may shorten your feline’s lifespan but also means it no longer has to suffer.
MY FINAL THOUGHTS
Thyroid disease is caused when the thyroid glands become enlarged and overactive, producing large amounts of the hormones T3 and T4. Initially, symptoms can be hard to spot as they can be seen as “positive” changes and usually become more prominent as the disease progresses.
Hyperthyroidism is treatable through surgery, medication, and iodine therapy when caught early enough. However, it can become fatal when left untreated. The signs your cat is dying of thyroid disease include substantial weight loss, vomiting and diarrhea, urinary incontinence, cardiac issues, and seizures.
At this point, euthanasia may be your best option. Your cat’s age, level of illness, and comorbidities need to be considered, though, so I would talk to your vet if you’re considering this option.