Feline Hyperthyroidism, Untreated | Hyperthyroidism in Cats Effects (2023)

Because of its sometimes subtle symptoms and the tendency for its onset to occur in middle and old age, feline hyperthyroidism can often be mistaken for changes that accompany aging in cats. Unfortunately, this means that many pet owners leave feline hyperthyroidism untreated. Doing so can cause pain and anguish for the cat. Feline hyperthyroidism is treatable and can be completely cured if spotted early. Leaving your cat's hyperthyroidism untreated, however, can result in many difficulties. It can even be fatal.

(Video) Hyperthyroidism in Cats

Untreated Cat Hyperthyroidism Long-Term

Veterinarians who have seen a cat with untreated feline hyperthyroidism often see cats that have grown very sick over the years. A cat with untreated hyperthyroidism may stop eating altogether. It may also exhibit blood in its stools. These are very serious symptoms, but internal changes are even more serious. Feline hyperthyroidism, untreated, can cause serious heart problems. This is because the cat’s heart must work harder to match the state of its overactive metabolism. This means that in addition to years of dietary distress, general restlessness and nervousness, and hair loss, a cat whose feline hyperthyroidism is untreated can suffer from heart problems that can be fatal.

(Video) Cat Hyperthyroidism- Symptoms, Diagnosis, and Treatment with Dr. Dan

Get Your Cat Tested

To spare your cat the serious medical problems that can arise from leaving feline hyperthyroidism untreated, it is important to begin treatment as soon as possible. That means keeping an eye out for symptoms and contacting your veterinarian immediately if and when they are spotted.

(Video) Feline Hyperthyroidism

The Only Effective Treatment for Feline Hyperthyroidism

If your cat tests positive, your veterinarian may recommend Radioactive Iodine Therapy for your cat's hyperthyroidism. This therapy is the most effective treatment option for treating feline hyperthyroidism. In this treatment, a radioactive iodine is injected. This iodine will eliminate abnormal thyroid tissue without harming surrounding tissues. After the injection, your cat will be monitored for a few days until his or her radiation levels are at an acceptable level.

(Video) Dr. Jan Recommends the Best Natural Treatment for Hyperthyroidism in Cats

This type of treatment is considered the most desirable because of its low risk of side effects and the fact that, in many cases, only a single treatment is needed. Surgery to correct the issue can be dangerous for cats that are already in poor health and cats will require hormone therapy following the surgery. Medication must be administered 1-3 times daily, and many cat owners find it difficult to give their cat pills daily. Medication also often comes with its own host of side effects, some of which can be dangerous. See a comparison of feline hyperthyroidism treatments.

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If your cat is exhibiting symptoms of feline hyperthyroidism, please contact your veterinarian immediately. Never leave feline hyperthyroidism untreated.

(Video) Hyperthyroidism in Cats

**Back to Feline Hyperthyroidism: An Overview

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(Video) Feline Hyperthyroidism: About Alternative Treatments


Do cats feel unwell with hyperthyroidism? ›

Other symptoms can include anxiety, vomiting, diarrhea, and increased thirst and urination. These excessive hormone levels push a cat's body into constant overdrive, which frequently leads to high blood pressure and a type of heart disease called hypertrophic cardiomyopathy.

How long can an old cat live with hyperthyroidism? ›

Most hyperthyroid cats do very well and can live another 5 years or more when they receive appropriate treatment. However, some cats continue to have health problems or even develop new ones as time goes on.

How long can hyperthyroidism go untreated? ›

In the case of thyroiditis, hyperthyroidism may be more short term, lasting about three months. After this time, you may develop hypothyroidism that can last at least a year, sometimes becoming permanent.

What are the complications of hyperthyroidism in cats? ›

Hyperthyroidism often leads to high blood pressure (hypertension) 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.

What are the final stages of hyperthyroidism in cats? ›

Late-stage hyperthyroidism in cats

If the illness keeps progressing despite the treatment recommended by the vet, or if the condition is discovered late, the cat might struggle with weight loss, kidney problems and even vision loss during the advanced stages of hyperthyroidism.

What are the worst symptoms of hyperthyroidism? ›

Symptoms of an overactive thyroid can include:
  • nervousness, anxiety and irritability.
  • hyperactivity – you may find it hard to stay still and have a lot of nervous energy.
  • mood swings.
  • difficulty sleeping.
  • feeling tired all the time.
  • sensitivity to heat.
  • muscle weakness.
  • diarrhoea.

How long can a 16 year old cat live with hyperthyroidism? ›

Prognosis for cats with hyperthyroidism is usually pretty good, provided that the disease was diagnosed and treated early on. Hyperthyroid cats can live a normal, healthy life well into their senior years!

How can I fatten up my cat with hyperthyroidism? ›

Hyperthyroid cats need high calorie and high protein diets to reduce the rate of weight loss and muscle wasting that accompanies the disease. Thyroxine (the major hormone produced by the thyroid gland) is one of numerous counter-regulatory or anti-insulin hormones.

Why do hyperthyroid cats meow so much? ›

When too much thyroid hormone (T4) is produced cats can become hyperactive and pace or meow. They often eat more and loose weight. The overactive thyroid may cause the heart to race. It is very easy to check for thyroid disease with a blood test.

Does hyperthyroidism get worse if untreated? ›

If hyperthyroidism isn't treated, it can cause some serious health problems, including: An irregular heartbeat that can lead to blood clots, stroke, heart failure, and other heart problems. An eye disease called Graves' ophthalmopathy. It can cause double vision, light sensitivity, and eye pain.

What happens if you ignore hyperthyroidism? ›

Over time, severe, untreated hyperthyroidism can lead to an irregular heartbeat, which in turn can cause blood clots, heart failure, and stroke. Treatment for hyperthyroidism is essential for preventing heart problems in people with Graves' disease, says Mikhael.

What happens if hyperthyroidism gets worse? ›

Possible Complications

Thyroid crisis (also called thyroid storm) is a sudden worsening of hyperthyroidism symptoms that may occur with infection or stress. Fever, decreased alertness, and abdominal pain may occur. People need to be treated in the hospital.

Are cats in pain with hyperthyroidism? ›

In addition, hyperthyroidism can cause hypertension or high blood pressure, and result in damage to the eyes, kidneys, and brain. Cats with untreated hyperthyroidism can also endure pain and a lower quality of life due to the symptoms of the disease.

Can hyperthyroidism cause neurological problems in cats? ›

Hyperthyroidism can cause neuromuscular signs in the cat, particularly involving the muscle, which can result in generalized weakness muscle atrophy, ventral neck flexion, fatigue, muscle tremors, and gait disturbances.

Can hyperthyroidism in cats lead to kidney failure? ›

If left untreated, hyperthyroidism can actually speed up the development or progression of kidney disease.

What not to feed a cat with hyperthyroidism? ›

It may be best to avoid:
  • SOY-containing foods.
  • BPA in canned food linings.
  • Fish.
  • Plastic food and water bowls (replace with glass, ceramic or metal)
  • Storing food in plastic containers.
  • Ultra-high or ultra low iodine diets.

How long can cats live on methimazole? ›

How long can a cat live on methimazole? This varies, but on average a cat may be expected to live anywhere from two to five years with hyperthyroidism being managed with methimazole.

Do cats ever recover from hyperthyroidism? ›

Fortunately, the vast majority of cats that develop hyperthyroidism can be treated very successfully and most cats will make a complete recovery.

What are 4 major clinical symptoms of hyperthyroidism? ›

The classic symptoms of hyperthyroidism include heat intolerance, tremor, palpitations, anxiety, weight loss despite a normal or increased appetite, increased frequency of bowel movements, and shortness of breath.

What causes hyperthyroidism to flare up? ›

A thyroid storm is a severe and sudden flare-up of symptoms caused by the metabolism going into overdrive, often due to triggers such as: infection. pregnancy. not taking your medication as directed.

What is silent hyperthyroidism? ›

Definition. Silent thyroiditis is an immune reaction of the thyroid gland. The disorder can cause hyperthyroidism, followed by hypothyroidism. The thyroid gland is located in the neck, just above where your collarbones meet in the middle.

Can untreated hyperthyroidism cause death? ›

Hyperthyroidism can indeed be a life-threatening condition if left untreated. It can lead to heart failure and stroke, and other problems in your cardiovascular system. However, hyperthyroidism can be treated and managed, and in some cases may resolve over time if the cause is removed.

What is an alternative to methimazole for cats? ›

Another approach for cats who cannot take methimazole involves a combination of potassium iodate and a heart medication called “propranolol.” Potassium iodate blocks the thyroid gland's uptake of iodine.

How much does it cost to treat a cat with hyperthyroidism? ›

Most cats seem to improve but never quite reestablish their prehyperthyroid state. Owners must be aware of this potential risk when selecting medication as their medical choice. Another misconception is that medical treatment costs less. Medications can cost $1 - $2 per day or approximately $350 to $700 per year.

What wet food is best for cats with hyperthyroidism? ›

Many hyperthyroid cats that are being treated with radioactive iodine therapy, methimazole or thyroidectomy can benefit from eating a high-protein, high-energy food like Instinct by Nature's Variety Original grain-free chicken recipe wet cat food or Tiki Cat Hanalei Luau wild salmon grain-free wet cat food.

Is dry food bad for cats with hyperthyroidism? ›

In reality, no dry food should be fed to cats – especially those with this disease. The high amount of carbohydrates in kibble is detrimental to a kitty's health, causing all sorts of disease. Questions remain about what exactly to feed a hyperthyroid cat – though we do have a suggestion below.

Is Tuna good for cats with hyperthyroidism? ›

Fish also contains a high amount of iodine, and that in itself may increase a cat's risk of developing hyperthyroidism.

What happens if I stop giving my cat thyroid medicine? ›

It is given one to three times daily and must be continued for the remainder of the pet's life. It takes several weeks for methimazole to reduce blood thyroid hormone levels to normal. If discontinued, levels will increase.

Can hyperthyroidism cause confusion in cats? ›

Vomiting. This is more common in households with multiple cats, and usually results from rapid overeating. Confusion, nighttime yowling and pacing. This is one of the most common behavioral symptoms of hyperthyroidism, and is often mistaken for dementia in older cats.

What are the symptoms of too much methimazole in cats? ›

Symptoms of too much methimazole in cats? Symptoms of excessive amounts of methimazole may include vomiting, diarrhea, depression, decreased appetite, facial itching, and changes in blood work.

Does hyperthyroidism reduce life expectancy? ›

The longer you have excess thyroid hormones circulating in your body, the greater the likelihood of an earlier death. On the other hand, controlling hyperthyroidism early in its course can result in less chance of developing cardiovascular disease and suffering its fatal complications.

Can hyperthyroidism cause failure to thrive? ›

Background: Thyroid dysfunction can induce developmental delay and failure to thrive in infancy. Congenital hypothyroidism is one of the common causes of these symptoms in infancy. By contrast, hyperthyroidism is a rare cause of these symptoms in infancy.

What foods reduce hyperthyroidism? ›

Foods to eat if you have hyperthyroidism
  • non-iodized salt.
  • decaffeinated coffee or tea (without milk or dairy- or soy-based creamers)
  • egg whites.
  • fresh or canned fruit.
  • unsalted nuts and nut butters.
  • homemade bread or breads made without salt, dairy, and eggs.
  • popcorn with non-iodized salt.
  • oats.

What happens if thyroid is neglected? ›

Untreated hypothyroidism can lead to serious complications, including heart disease and nerve damage. In rare cases, it can be fatal. Most people with hypothyroidism have to take thyroid hormone replacement long term. You will need ongoing thyroid level checks to ensure you are on the right dose.

Can hyperthyroidism be temporary? ›

Depending on the severity, thyroiditis may or may not produce any symptoms or need to be treated. The inflammation releases an excessive amount of thyroid hormone, leading to temporary hyperthyroidism. As the thyroid “burns out,” the thyroid then often becomes underactive.

What are early warning signs of thyroid problems? ›

Early warning signs of thyroid disorder
  • Weight loss.
  • Anxiety.
  • Irritability.
  • Irregular menstrual periods.
  • Heat sensitivity.
  • Vision problems.
  • Trouble sleeping.
  • Enlarged thyroid gland or goiter.

What is the most severe form of hyperthyroidism? ›

The most severe form of hyperthyroidism is thyroid storm. This acute condition is characterized by very rapid heart rate, fever, hypertension (high blood pressure), and certain gastrointestinal and neurological symptoms and may result in heart failure, hypotension (low blood pressure), shock, and death.

Does hyperthyroidism get worse with stress? ›

“Stress has a negative impact on the immune system. So if you're really stressed, it can make the symptoms of hypothyroidism worse,” Hatipoglu says. Even if your hypothyroidism is well controlled, high stress causes your body to release adrenaline and cortisol.

Does stress make hyperthyroidism worse? ›

Thyroid conditions such as Grave's disease (hyperthyroid) and Hashimoto's thyroiditis (hypothyroid) are worsened by chronic stress so learning ways to lessen stress is your key to better health.

How long does it take for a cat to recover from hyperthyroidism? ›

Radio-iodine kills thyroid tumours over time; most cats go back to normal thyroid hormone levels within a couple of weeks, but it can take up to 6 months.

Do cats with hyperthyroidism meow a lot? ›

One of the most common problems in an older cat is an overactive thyroid gland. This is called “hyperthyroidism”. When too much thyroid hormone (T4) is produced cats can become hyperactive and pace or meow.

How do you treat senior cat hyperthyroidism? ›

Treatment option: Oral medication.

One treatment option involves the use of an oral medication called methimazole (Tapazole®). Methimazole works by reducing the thyroid gland's ability to produce T4. This medication is readily available and relatively inexpensive.

Can methimazole hurt my cat? ›

In cats, the most common side effects of methimazole/carbimazole administration are gastrointestinal (hyporexia to anorexia, vomiting, and diarrhea). Most of the gastrointestinal side effects can be controlled by discontinuation of the medication and supportive care.

When should methimazole be stopped? ›

Stop methimazole if the count is less than 1000 per ml. Treat fever or any apparent infections with intravenous antibiotics.

What happens if my cat stops taking methimazole? ›

Methimazole. Methimazole is an oral (pill) medication that works by blocking the production of thyroid hormone. The effects of this drug are completely reversible. If you stop giving this drug, most cats quickly return to the same thyroid condition they had prior to using the medication.


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