Hyper Thyroid Symptoms In Cats

Common Symptoms Of Hyperthyroidism In Cats

• A ravenous appetite
• Weight loss despite this increase in appetite
• Increased thirst
• Agitated, restless or irritable
• Occasional vomiting
• A scruffy unkempt or matted coat

Not every cat will show all of these signs. As you can see in the case of Merry and Mungo Jerry, this feline pair were not your typical hyperthyroid cats. They didnt have any of the other classic symptoms, they were still healthy weights and were in good condition.

Late Stage Hyperthyroidism In Cats

Hyperthyroidism is a common affliction of senior cats and the most common endocrine disorder in the feline. Over the past several decades the incidence of hyperthyroidism in felines has been on the rise, though no one is certain why this is the case. Theories abound: canned cat food, improper levels of iodine, alien motherships while the jury is still out, the best one can do is be aware of the signs and seek veterinary care if you suspect this disease.

So what is hyperthyroidism, exactly? The thyroid gland, a little blob of tissue at the base of the throat, produces hormones that regulate the bodys metabolism. Most cases of hyperthyroidism stem from benign tumors that form in the gland these tumors do not spread, but pump out high levels of thyroid hormone. The results are what you would expect for a cat with a thundering metabolism: they eat like crazy yet still lose weight. Left untreated, the disease can lead to life threatening cardiac issues, so it does need to be addressed.

The good news is, hyperthyroidism is easily diagnosed with a blood test and can be treated a variety of ways. Most veterinarians begin by treating with oral medications, which can be adjusted as needed. Some cats respond to dietary therapy with a prescription low iodine diet. Once stable, owners can continue with the oral medications for life or can look for a more permanent solution: either surgery or radioactive iodine.

Unfortunately, cats can die from thyroid disease.

An Example Of Hyperthyroidism With Merry And Mungo Jerry

Very recently two 14 year old siblings, Merry and Mungo Jerry, visited our Penistone surgery for their booster vaccinations. Both had lost a little weight and after our vet asked a few questions their owner thought that Mungo Jerry was drinking perhaps a little more than normal. On examination, both cats had enlarged thyroid glands in their neck and Merrys heart rate was slightly higher than normal. Routine bloods were taken, including checking their Total Thyroid levels which revealed that they both had high TT4 levels confirming both cats had Hyperthyroidism.

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What Should A Hyperthyroid Cat Not Eat

A hyperthyroid cat should not eat any food that contains iodine, such as seafood or salt.

Cats have a higher prevalence of endocrine disorders such as hyperthyroidism. Hyperthyroid symptoms in cats include weight loss, muscle wasting, and fatigue. A cats metabolic system suffers from severe complications, including hyperglycemia, diabetes, and glucose intolerance. It is necessary for a cats body to consume its own muscle tissue in order to survive on carnivorous diets. Hyperthyroid cats require a large amount of protein to make their bodies work properly. Cats, like human beings, lose their muscle mass over time. The cats insulin sensitivity will be improved if it eats a diet low in carbohydrates, and his or her glucose metabolism will be stabilized. A hyperthyroid cats diet should consist primarily of dry food, or it should be completely eliminated.

What Causes Feline Hyperthyroidism

The majority of cases of hyperthyroidism in cats are as a result of a benign change to one or more of the thyroid glands called hyperplasia or adenoma. These cause enlargement of the gland and cause it to produce thyroid hormone in an uncontrolled way. Despite extensive investigations, no one, single cause has been found to explain the development of these changes, however, it appears to be more common in cats that live entirely or predominantly indoors and those that consume tinned cat food. Fire retardant chemicals have also been suggested as a cause but this has also not been conclusively proved.

In a small proportion of cases , hyperthyroidism can be caused by a malignant cancer of the thyroid gland called thyroid carcinoma.

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Hyperthyroidism In Cats Life Expectancy

Untreated, a hyperthyroid cat has a shortened life expectancy. This is due to complications such as high blood pressure, kidney disease, and heart failure. How quickly the cat deteriorates depends on lots of factors and varies from cat to cat.

Your veterinarian is best placed to guide you on life expectancy. But on average, cats live for months, or even a year or so, after diagnosis.

The outlook with treatment is much better. Many cats now survive for years after diagnosis, provided they receive treatment early before the heart is badly damaged.

How Is Hyperthyroidism In Cats Treated

Once the diagnosis of hyperthyroidism has been confirmed, there are here are four main forms of treatment, with the best choice depending on the cats individual situation.

Each different treatment choice carries a different price tag, and this will vary from area to area: you should ask your vet for a full treatment estimate at the start, so that you know how much you need to budget for.

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Battling Feline Hyperthyroidism: A War We Can Win

by BEVS | May 13, 2022 | Pet Health |

If you have a middle-aged or senior cat, your list of worries might be longer than it was a few years ago. Although certain conditions and diseases can find cats of any age, some tend to affect older kitties. Of these, hyperthyroidism is one of the most common.

We begin to consider cats to be seniors at age 6 or 7, and so cat owners need to understand and recognize the signs of hyperthyroidism. Read on to get yourself up to speed.

Recovery And Management Of Hypothyroidism In Cats

The goal of oral medication for hypothyroidism in cats is to improve the clinical signs of the disease. Follow-up bloodwork is important to assess the absorption and appropriate dosing of medication.

An overdose of medication can have significant consequences, so your cats blood levels of T4 are an important indicator of appropriate regulation.

In cats with acquired iatrogenic hypothyroidism after treatment for hyperthyroidism, additional follow-up testingincluding complete blood count, serum biochemistry, and urinalysisis recommended.

With some of these cats , hypothyroidism can be reversed when your vet finds the ideal dosage of long-term hyperthyroid medication for your cat.

Cats that were treated for hyperthyroidism with permanent treatments like surgery or radioactive iodine that led to hypothyroidism will need the long-term oral thyroid hormone.

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How Vets Diagnose Hypothyroidism In Cats

Diagnosis of hypothyroidism in cats requires blood samples to be drawn and put through a specific test called a thyroid panel. A feline thyroid panel consists of multiple measurements.

In a cat with hypothyroidism, their total T4 measurement is usually low. However, certain medications as well as a syndrome called euthyroid sick could also be responsible for lowering your cats total T4, so additional testing may be required.

This additional testing may consist of a blood sample for measuring free T4 , T3, and TSH .

In kittens with congenital hypothyroidism, X-rays may reveal bony changes. The thyroid hormone is essential for normal development of a kittens skeletal and nervous systems, so a lack of the hormone leads to changes seen in these systems.

Your veterinarian may also see high cholesterol and anemia on a complete blood count and chemistry panel. While these issues are not unique to a diagnosis of hypothyroidism, seeing them in your cat may lead your vet to order more specific tests, including thyroid measurements.

What Causes Cats To Be Hyperthyroid

Hyperfunctioning thyroid nodules cause hyperthyroidism. But what causes the thyroid to go haywire?

There are several theories about what causes cats to become hyperthyroid:

• Rarely, thyroid cancer
• Some reports have linked hyperthyroidism in cats to some fish-flavored canned food diets
• Research has pointed to flame-retardant chemicals that are used in some furniture and carpeting and circulated in house dust
• Advancing age increases risk

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Other Thyroid Problems In Cats

Anything that prompts the thyroid glands to produce too much thyroid hormone, will cause symptoms of hyperthyroidism. Commonly this is due to hyperplasia or over-enthusiastic glandular tissue.

Alternatively, a relatively harmless cystic type tumor called an adenoma can affect the thyroid glands. This is not too much of a worry, because the main symptoms are those of hyperthyroidism.

However, a small percentage of cases are caused by a more serious type of tumor. A cancer of the thyroid gland called a carcinoma is more aggressive.

Which Treatment Do We Recommend

There are both advantages and disadvantages for all treatment types and we will consider all aspects of your cats situation when recommending a treatment method. For an extremely anxious, elderly cat with significant kidney disease, we would probably recommend medication or dietary management. The same may be true for owners without pet insurance where a large lump sum simply isnt possible, which is absolutely fine.

However, in most cases, if funds allow and especially if your cat is relatively young , we are likely to recommend radioactive iodine therapy as it is generally considered to be the gold standard treatment offering the best results for your cat. No anaesthetic or surgical procedure is required so the risks are minimal and it offers the highest chance of a complete cure, with minimal inconvenience for your cat other than having to sit in a nice hospital kennel for a while.

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Diagnosing Hyperthyroidism In Cats

Your vet will begin by asking you for a detailed history of your cats signs and symptoms including litter box habits, weight changes, eating and drinking habits and amounts, activity levels, and changes in behavior/moods. After a thorough physical exam, diagnostic tests such as blood work, x-rays or ultrasound, and urinalysis will be recommended to determine a diagnosis.

How To Treat Hyperthyroidism In Cats

There are a number of different treatments for hyperthyroidism available. The most appropriate treatment depends on individual circumstances involving both the cat and the owner.

Their overall health is the main factor in determining the best treatment path. Meanwhile, the financial situation and ability to medicate the feline regularly are important considerations, too.

Feline thyroid problems can be treated in the following ways:

• Surgical removal of the thyroid glands
• Medication to control thyroid hormone levels
• Radioactive iodine therapy to target the thyroid gland
• Dietary therapy to help control thyroid hormone levels

In this section, well take a look at each treatment option in more detail, including information about which kind of treatment is most appropriate in different situations, and whether radioactive iodine therapy could be the best solution for targeting abnormal thyroid cells without impacting the cats overall health.

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Options For Cat Thyroid Medication And Treatment

Vets will usually use four treatments for hyperthyroidism: dietary therapy, medication, surgery, and radioactive iodine therapy.

The correct course of treatment will depend on a wide variety of factors, including the specific hormones that are disrupted, the levels of those hormones, and other symptoms displayed by your pet.

Radioactive Iodine Therapy For Hyperthyroidism

Radioactive iodine therapy is considered the safest and most effective treatment. The thyroid stores iodine, and small amounts of radioactivity can stop the overactive gland from producing too much thyroid hormone.

The amounts of radioactivity are too small to affect the rest of your cats body, and it is eventually passed out of the body via urine. No general anaesthetic is needed, and medication is not required long-term.

There are strict laws in the UK controlling radioactive substances, which means that a cat having radioactive iodine therapy will have to stay in a specialised isolation unit between five days and four weeks.

Radioactive iodine is very safe and carries no significant risk or side effects. It is only offered at a few UK veterinary hospitals, so there may be some distance to travel for treatment.

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How Is Hyperthyroidism In Cats Diagnosed

To diagnose hyperthyroidism, your veterinarian will begin by giving your cat a physical exam and checking the catâs neck for an enlarged thyroid gland.

If the veterinarian suspects that your cat has hyperthyroidism, they will likely conduct a few more tests, such as:

• A blood chemistry panel that measures thyroid hormone levels
• An ultrasound of the heart

Hyperthyroidism can sometimes predispose a cat to develop other medical conditions. For instance, two complications of hyperthyroidism in cats are high blood pressure and heart disease. Your veterinarian will check for these conditions and evaluate your catâs overall health.

How Is Hyperthyroidism Diagnosed

Diagnosis of feline hyperthyroidism is generally straightforward . The first step is to determine the blood level of one of the thyroid hormones, called total thyroxine . Usually, the TT4 level is so high that there is no question as to the diagnosis.

Occasionally, a cat that is suspected of having hyperthyroidism has a TT4 level within the upper range of normal. When this occurs, a second test, usually either a free T4 by equilibrium dialysis or a T3 suppression test is performed. If these tests are not diagnostic, a thyroid scan can be performed at a veterinary referral center, or the TT4 can be measured again in a few weeks.

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What Are The Signs Of Hyperthyroidism In Cats

The most common sign of hyperthyroidism in cats is weight loss despite an increased appetite. Other common signs include vomiting, diarrhea, hyperactivity, drinking and urinating more than normal, and an unkempt hair coat. Because the disease develops gradually, signs are often easy to miss at first.

Hyperthyroidism often leads to high blood pressure and heart disease. The high blood pressure is due to the increased pumping pressure of the heart. In some cats, the blood pressure becomes so high that the retina detaches from the back wall of the eye, resulting in sudden blindness. Heart disease develops because the heart must pump faster and more forcefully to meet the bodys increased metabolic demands . To compensate for this increased workload, the muscles of the heart thicken, causing the heart to enlarge and eventually fail. Untreated hyperthyroidism is almost 100 percent fatal.

Hyperthyroidism In Cats: What Does It Mean For Your Kitty

By Katelyn Son | Updated December 05, 2022

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Hyperthyroidism in cats is a common condition in middle-aged to older cats. The clinical signs of feline hyperthyroidism include increased appetite with weight loss. Left untreated, cats develop high blood pressure, kidney disease and heart problems.

With treatment, most cats with hyperthyroidism can lead a normal life for months and years to come.

There are lots of treatment options for feline hyperthyroidism. This includes special food, medication such as methimazole, surgical removal, or radioactive iodine treatment. Your veterinarian is best placed to discuss which treatment is best suited to your cat.

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Diet Control For Hyperthyroidism

Studies have shown that an iodine-restricted diet alone can control thyroid hormone levels, without the need for medication. Without iodine, the thyroid gland cannot make any hormones. Hills Pet Nutrition produces a prescription diet for cats with strictly controlled iodine levels.

However, on this diet, your cat must not consume any other food or liquid apart from water. Obviously, this solution wouldnt be practical for a cat that has access to the outdoors, or a cat that lives with others even the smallest amount of stolen food will allow hormones to be produced. While there have been no reported side effects, its possible that very low iodine diets can affect the immune system, although there is no evidence of this.

The diet is successful in approximately 90% of cases. Usually, if it doesnt work it is because the cat is getting food from elsewhere.

Skin And Coat Changes

A thyroid problem will cause the cat to have a dull and coarse coat.The cat may lose significant amounts of hair, but there will be no baldpatches, but the coat will get thinner.

The skin will be dry and flaky if the cat suffers fromhypothyroidism. An excess of thyroid hormones may lead to an oily skinwith acne and common skin infections.

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Symptoms Of Hyperthyroidism In Cats

Here are the major symptoms of hyperthyroidism that you should look for in your cat:

• Drinking more than usual
• Peeing more than usual
• Heart murmur rapid heart rate an abnormal heartbeat known as a gallop rhythm
• Hyperactivity/restlessness
• Enlarged thyroid gland, which feels like a lump on the neck
• Thickened nails

Less than 10% of cats suffering from hyperthyroidism exhibit atypical signs such as poor appetite, loss of appetite, depression, and weakness.

Cat Diet For Hyperthyroidism

Dietary therapy for cats with hyperthyroidism usually involves restricting the amount of iodine that they have in their diet. The approach has been met with criticism, with some studies showing that iodine restriction can be just as dangerous to your pet as hyperthyroidism itself.

This will usually be an option chosen when other methods are not appropriate, perhaps due to other medical conditions.

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Surgical Thyroidectomy For Hyperthyroidism In Cats

Surgery isnt a great treatment for cats with existing medical conditions that affect the kidneys or heart, overweight cats, or older cats, but it can still provide a permanent cure for the condition in younger cats with otherwise good health.

With hyperthyroid cat surgery, the thyroid glands are removed entirely, under a general anesthetic. These glands are close to other vital glands, however, such as the parathyroid glands. If these are damaged during the surgery, there can be problems with calcium levels in the blood. Because of this, surgery is often the last resort for cats with thyroid disease.