How do you know if your cat has hyperthyroidism?
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.
What is the most common endocrine disease in cats?
Hyperthyroidism results when the thyroid gland over-produces thyroid hormones. It’s the most common endocrine disease of cats older than 8-years-old. (An endocrine disease is a disease of the organs that make and secrete hormones.) In almost 99 percent of the cases, hyperthyroidism is caused by a benign (non-cancerous) tumor of the thyroid gland.
What is the butterfly shaped thyroid gland?
The butterfly-shaped thyroid gland is located in the neck, with one lobe on each side. It plays an important role in regulating the body’s “engine,” or metabolic rate. When the thyroid gland produces an excessive amount ...
How often can you give a cat Felimazole?
Felimazole is available only with a veterinarian’s prescription. The drug is typically given by mouth every 12 hours. Your veterinarian will adjust the dose, as necessary, based on the results of your cat’s blood tests and response to treatment.
What happens if a cat has low platelets?
low platelets—platelets are found in the blood of all mammals and help with blood clotting. When a cat has low platelets, its blood can’t clot as well, which may lead to bleeding problems; and. severely low level of neutrophils in the blood—neutrophils, a type of white blood cell, are part of the body’s immune system.
Why is my cat blind?
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 ...
Why does my cat's heart enlarge?
Heart disease develops because the heart must pump faster and more forcefully to meet the body’s increased metabolic demands (du e to the cat’s revving engine). To compensate for this increased workload, the muscles of the heart thicken, causing the heart to enlarge and eventually fail.
What Is Hyperthyroidism?
Hyperthyroidism, the opposite of hypothyroidism, is also known as thyrotoxicosis and occurs when the thyroid gland becomes enlarged and produces extra hormones. The thyroid gland is located in the neck and makes hormones called T3 and T4, which play a role in a variety of bodily functions, including metabolism and body temperature regulation.
Causes of Hyperthyroidism in Cats
There are two types of tumors that cause hyperthyroidism in cats. Most cases of hyperthyroidism are due to a benign tumor called an adenoma but in rare cases, a cancerous tumor called an adenocarcinoma is the cause. Both tumors cause the thyroid gland to become enlarged but no one knows what causes either type of tumor to grow to begin with.
Diagnosing Hyperthyroidism in Cats
If your cat is showing symptoms of hyperthyroidism, a visit to their veterinarian is warranted. The vet will perform a physical examination and obtain your cat's history before recommending blood screening be performed. Sometimes, enlarged thyroid glands can be detected during the physical exam.
Treatment of Hyperthyroidism in Cats
There are four ways to treat a cat that has been diagnosed with hyperthyroidism: dietary treatment, surgery, medication, and radioactive iodine therapy. Each option has its pros and cons and may not be right for every cat but the majority of cat owners opt to treat the disease with either diet or medication.
How to Prevent Hyperthyroidism in Cats
Because no one knows what causes a cat to develop the tumors that cause hyperthyroidism, there is no way to prevent the disease. The best thing you can do as a cat owner is to address any symptoms of hyperthyroidism as soon as you see them. Additionally, treating the disease promptly upon diagnosis will help prevent other problems from developing.
Risk Factors for Hyperthyroidism in Cats
While no specific cat breed has a definitively higher risk for developing hyperthyroidism than another, any cat senior is at a greater risk for the disease. Some studies suggest that cats that eat mostly canned food, especially fish-based canned food, are at increased risk.
What is the treatment for a cat's thyroid?
Radioactive iodine therapy. This treatment involves injecting your cat with iodine directly into their bloodstream. The cat’s thyroid absorbs the iodine and the radiation destroys any abnormal thyroid tissue, without damaging other tissues in the cat’s body.
How to treat thyroid in cats?
Treatment options include: Medication. Anti-thyroid drugs can help reduce the production of thyroid hormones in cats. The drug most commonly is provided as a twice-daily medication that must be given for the remainder of the cat's life. Anti-thyroid drugs may also come in the form of a gel, which can be applied to the skin.
Why do cats have thyroid glands?
Cats have two thyroid glands in their neck that help regulate metabolism. Sometimes these glands can expand and overproduce thyroid hormone. This can be problematic because thyroid hormone affects other organs in the cat’s body, most significantly the heart. Most of the time, an enlarged thyroid gland is caused by a noncancerous tumor, ...
What age does hyperthyroidism occur in cats?
Hyperthyroidism most commonly occurs in cats around the age of 13. Cats have two thyroid glands in their neck that help regulate metabolism. Sometimes these glands can expand and overproduce thyroid hormone.
What are the complications of hyperthyroidism in cats?
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 cat’s overall health. Continued.
Can cats have thyroid issues?
A blood chemistry panel that measures thyroid hormone levels (most cats will have an elevated amount of thyroid hormone in their bloodstream) Hyperthyroidism can sometimes predispose a cat to develop other medical conditions.
Which breed of cat has the highest risk of hyperthyroidism?
No specific breed is known to have a greater risk of hyperthyroidism, though some breeds such as Siamese, Persian, and Himalayan cats appear to experience the disease less compared with others.
Why is my cat hyperthyroid?
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 (PBDEs) that are used in some furniture and carpeting and circulated in house dust.
What is the cause of hyperthyroidism in cats?
Hyperthyroidism in cats is a disease that’s usually caused by a benign tumor within the thyroid gland. This tumor causes an overproduction of the thyroid hormone called thyroxine. One of the primary functions of this thyroid hormone is to regulate an animal’s metabolism.
How to treat a cat with radioiodine?
Giving your cat a medication called methimazole is probably the most common treatment choice. It’s administered by mouth in pill form, or it can be formulated by a compounding pharmacy into a transdermal gel that can be applied to your cat’s ear. Methimazole is often given before radioiodine treatment or surgery to stabilize your cat’s clinical signs.
Why do cats lose weight?
Cats with too much thyroid hormone have a greatly increased metabolic rate, which leads them to lose weight despite having a ravenous appetite. Other symptoms can include anxiety, vomiting, diarrhea, and increased thirst and urination.
What is the thyroid gland in cats?
In cats, the thyroid gland has two parts, with one on each side of the trachea (windpipe), just below the larynx (voice box). The thyroid gland makes several different hormones (mostly thyroxine, or T4). These thyroid hormones affect many of your cat’s body processes: Regulation of body temperature. Metabolism of fats and carbohydrates.
What is the gold standard for hyperthyroidism?
The gold standard therapy is radioiodine (I 131) treatment, which can cure the hyperthyroidism in most cases. Daily medication (methimazole) or feeding a low-iodine diet are good options when radioiodine therapy is not an option due to financial considerations or the cat’s overall health.
How does thyroid affect cats?
These thyroid hormones affect many of your cat’s body processes: Regulation of body temperature. Metabolism of fats and carbohydrates. Weight gain and loss. Heart rate and cardiac output. Nervous system function. Growth and brain development in young animals. Reproduction. Muscle tone.
What is hyperthyroidism in cats?
Hyperthyroidism occurs when there is an elevated level of thyroid hormone produced by one or both of the thyroid glands in a cat. It is an astonishingly common problem in cats: it’s seen more than any other cat hormone problem, and in one recent study of cats over the age of ten being blood sampled, 21% had elevated thyroid hormones.
Why do cats die from hyperthyroidism?
The ultimate cause of death is not usually associated with hyperthyroidism: cancers and kidney disease are the most common reasons, and these are common in all elderly cats.
How to tell if a cat has hyperthyroidism?
What Are The Symptoms (Signs) Of Hyperthyroidism In Cats? 1 Changes in the cat’s behavior and habits. 2 A formerly placid, easy going cat might become more agitated and more irritable. 3 The appetite is often affected, with changes in favorite foods, as well as a significantly increased appetite. 4 Increased thirst. 5 Increased urination, sometimes with accidents in the house. 6 Increased vocalization, with cats howling and yowling more than before. 7 Intermittent vomiting. 8 The most telltale sign is weight loss despite an increased appetite.
What can go wrong with thyroid glands?
What Can Go Wrong With The Thyroid Glands? Too much thyroid hormone causes an animal to behave as if their accelerator pedal is permanently pushed down to the floor, while if there isn’t enough thyroid hormone, the animal becomes sleepy, lacking energy and becoming slow and lethargic.
How old is too old to have hyperthyroidism in cats?
Hyperthyroidism is a very common condition in cats, especially over the age of ten years old .
How do you know if your cat is irritable?
Often the cat carer notices a number of symptoms developing in their pet. Changes in the cat’s behavior and habits. A formerly placid, easy going cat might become more agitated and more irritable. The appetite is often affected, with changes in favorite foods, as well as a significantly increased appetite. Increased thirst.
What is a blood sample for hyperthyroidism?
A blood sample is a key part of confirming the diagnosis of hyperthyroidism. Vets often start by carrying out a so-called “minimum database”, which means hematology (checking the red and white blood cells) and a biochemistry panel (measuring a range of enzymes and chemicals in the blood stream),
What is the best treatment for hyperthyroidism in cats?
Radioiodine therapy. Radioiodine (or ‘radioactive iodine’) therapy is the gold-standard treatment for cats with hyperthyroidism. You can read our webpage detailing the full list of advantages, but in summary it’s your best chance of a low-risk, permanent cure for your cat. Unlike medication and diet, it’s designed to be a one-off treatment, ...
How long does it take for a cat to have a second thyroid operation?
Since 75% of cases involve both thyroid glands, your cat would probably need a second operation, typically within 18 months.
Why is my cat not a candidate for surgery?
Your vet may decide that your cat isn’t even a candidate for surgery because the risks are just too high.
Can hyperthyroidism be cured?
Hyperthyroidism can be cured with surgery and, if successful, no further medication is required. However: Surgery is particularly risky for hyperthyroid cats – not just because they’re usually older, but because they’re likely to have a very fast heart rate.
Can cats get cancer?
Since this isn’t a cure, your cat’s tumour will continue to grow – which, research has suggested, could result in the tumour becoming cancerous. Research suggests that diets which are extremely low in iodine may have a negative effect on your cat’s immune system.
Can a cat's thyroid be cancerous?
When not removed or destroyed, thyroid tumours can turn cancerous. Research indicates that whereas fewer than 2% of feline hyperthyroid tumours normally tend to be cancerous, 20% of them are found to be malignant in cats treated with medication for 4 years or more.
How do you know if your cat has hyperthyroidism?
Some of the most common signs of hyperthyroidism to watch out for are: Increased appetite, coupled with weight loss. Excessive thirst.
How many cats respond to thyroid medication?
Treatment failures of hyperthyroidism in cats. More than 9 in 10 cats respond well to recommended treatment, although it won’t always work well for everyone. If medication isn’t working for your cat, it may just mean trying the alternative tablet.
What is the safest treatment for thyroid problems?
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.
Why does my thyroid stop working?
This is mainly due to parathyroids – smaller glands attached to the thyroid glands – which control the level of calcium in the blood. When a thyroid gland is removed , the parathyroids might stop working, which can be permanent.
How does the brain control thyroxine levels?
The brain controls the level of thyroxine by telling the thyroid gland how much to make. Growth in the thyroid gland can cause hyperthyroidism, producing more active cells. However, these cells can develop out of control and instead produce thyroxine continually instead of the amount that is needed. High levels of thyroxine in cats can force the ...
What is the condition in which the thyroid gland is overactive?
Feline hyperthyroidism is an extremely common condition that occurs when the thyroid gland in the neck becomes overactive. The thyroid glands produce a hormone (thyroxine) that controls the animal’s metabolic rate – i.e how the body uses energy. The brain controls the level of thyroxine by telling the thyroid gland how much to make.
How long does a cat have to be in isolation for iodine?
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.
Overview
- Hyperthyroidism (overactive thyroid) occurs when your thyroid gland produces too much of the hormone thyroxine. Hyperthyroidism can accelerate your body's metabolism, causing unintentional weight loss and a rapid or irregular heartbeat.Several treatments are available for hyperthyroidism. Doctors use anti-thyroid medications and radioactive iodine to slow the production of thyroid hormones. Sometimes, hyperthyroidism treatment involv…
- In hyperthyroidism, an irritation of your thyroid known as thyroiditis allows too much thyroid hormone to enter your blood. This can lead to pain and discomfort. Thyroiditis can also occur as the result of pregnancy. This is usually short-term.
Treatment
- Hyperthyroidism can be treated with antithyroid medications that interfere with the production of thyroid hormones (primarily methimazole; propylthiouracil is now used only for women in the first trimester of pregnancy). Another option is radioactive iodine therapy to damage the cells that make thyroid hormones. In rare cases in which women do not respond to or have side effects from these therapies, surgery to remove the thyroi…
- According to the American Thyroid Association, theres no cure for hypothyroidism. However, there are medications that can treat the disease. The goal of the medication is to improve your bodys thyroid function, restore hormone levels, and allow you to live a normal life.
- 1. Medication - the thyroid gland relies on iodine to make the thyroid hormones. Anti-thyroid drugs work by interfering with the gland's ability to use iodine. Around one in four people will experience a prolonged period of remission after one year or more of anti-thyroid medication. Side effects of the medications include skin rashes and joint pain. Patients on these drugs who experience fever or flu-like symptoms should see their doctor immed…
- Exact treatment depends on the cause of the condition. There are three main methods of treatment for thyrotoxicosis:
Signs And Symptoms
- Weight loss and increased appetite are among the most common clinical signs of this condition. Weight loss is seen in 95 to 98 percent of hyperthyroid cats, and a hearty appetite in 67 to 81 percent. Excessive thirst, increased urination, hyperactivity, unkempt appearance, panting, diarrhea and increased shedding have also been reported. Vomiting is seen in about 50 percent of affected cats. Clinical signs are a result of the effect of increased T4 lev…
- Less than 10 percent of cats suffering from hyperthyroidism are referred to as apathetic. These patients exhibit atypical signs such as poor appetite, loss of appetite, depression, and weakness.
- Hyperthyroidism can mimic other health problems, which can make it difficult for your doctor to diagnose. It can also cause a wide variety of signs and symptoms, including: 1. Unintentional weight loss, even when your appetite and food intake stay the same or increase 2. Rapid heartbeat (tachycardia) — commonly more than 100 beats a minute 3. Irregular heartbeat (arrhythmia) 4. Pounding of your heart (palpitations) 5. Increased appetite 6. Nervo…
- The symptoms of hyperthyroidism include the following: 1. fatigue or muscle weakness 2. hand tremors 3. mood swings 4. nervousness or anxiety 5. rapid heartbeat 6. heart palpitations or irregular heartbeat 7. skin dryness 8. trouble sleeping 9. weight loss 10. increased frequency of bowel movements 11. light periods or skipping periods.Some people may develop a goiter, which is an enlarged thyroid gland that feels like a swelling in the fro…
Diagnosis
- Because several common diseases of older cats-diabetes, inflammatory bowel disease, intestinal cancer and chronic kidney failure-share some of the clinical signs of hyperthyroidism, a battery of tests is in order. A CBC, chemistry panel and urinalysis alone will not diagnose hyperthyroidism, but they can certainly rule out diabetes and kidney failure. Hyperthyroid cats may have normal findings on the CBC and urinalysis, but the chemistry pan…
- The signs of feline hyperthyroidism can overlap with those of chronic renal failure, chronic hepatic disease, and cancer (especially intestinal lymphoma). These diseases can be excluded on the basis of routine laboratory findings and thyroid function tests. Your veterinarian will conduct a battery of tests to zero in on a reliable diagnosis. Thoracic radiography and echocardiography may be useful in assessing the severity of myocardial di…
- Hyperthyroidism is diagnosed based on symptoms, physical exam, and blood tests to measure levels of thyroid stimulating hormone (TSH) and thyroid hormones T3 and T4. Your doctor may also decide to order either an ultrasound or a nuclear medicine scan of your thyroid to see if it has nodules, or whether it is inflamed or overactive.
- In the United States, hypothyroidism is more common than hyperthyroidism. However, its not uncommon to have an overactive thyroid and then an underactive thyroid, or vice versa. Finding a skilled doctor who specializes in the thyroid, typically an endocrinologist, is an important part of your treatment plan.
Cause
- Hyperthyroidism can be caused by a number of conditions, including Graves' disease, Plummer's disease and thyroiditis.Your thyroid is a small, butterfly-shaped gland at the base of your neck, just below your Adam's apple. The thyroid gland has an enormous impact on your health. Every aspect of your metabolism is regulated by thyroid hormones.Your thyroid gland produces two main hormones, thyroxine (T4) and triiodothyronine (T3), tha…
- The thyroid gland makes the hormones thyroxine (T4) and triiodothyronine (T3) that play an important role in the way your whole body functions. If your thyroid gland makes too much T4 and T3, this is defined as hyperthyroidism. The most common cause of hyperthyroidism is the autoimmune disorder Graves’ disease. In this disorder, the body makes an antibody (a protein produced by the body to protect against a virus or bacteria) call…
- Hashimotos thyroiditis is the most common cause of hypothyroidism. With this condition, your body attacks its own immune system. Over time, this attack causes the thyroid to stop producing hormones as it should which leads to hypothyroidism. Like many autoimmune diseases, Hashimotos thyroiditis occurs more frequently in women than men. As its name suggests, hyperthyroidism occurs when your body makes too much of the thyroi…
- The main cause of thyrotoxicosis is hyperthyroidism, which is an overactivity of the thyroid gland resulting in it producing excess levels of thyroid hormones. If the hyperthyroidism is due to an autoimmune cause, it is called Graves' disease. Other rarer causes of thyrotoxicosis include excessive intake of thyroid hormone in patients treated for hypothyroidism (an underactive thyroid gland) and sometimes, inflammation of the thyroid gland (thy…
Pathophysiology
- The most common difference between the two diseases relates to hormone levels. Hypothyroidism leads to a decrease in hormones. Hyperthyroidism leads to an increase in hormone production.
- Thyrotoxicosis is the name given to the clinical effects experienced due to an excess of thyroid hormones in the bloodstream. Hormones produced by the thyroid gland control how fast or slow the body works (metabolic rate). Too much thyroid hormone (thyroxine and triiodothyronine) speeds up the metabolism and results in the signs and symptoms of thyrotoxicosis.
- When functioning correctly, the thyroid is able to properly respond to changes in temperature by adjusting the bodys basal metabolic rate (BMR) and releasing hormones to promote cellular release (aka sweating) or retention of heat, allowing the body to remain at a comfortable temperature. With hyperthyroidism, the body cannot regulate these hormones as easily, therefore, many patients have difficulty adjusting to the heat, causing them to becom…
Epidemiology
- Thyroid disease tends to be commoner in women than men (up to 10 times more). Thyrotoxicosis can occur at any age and there is a 1 in 100 chance of a woman developing it in her lifetime and a 1 in 1,000 risk for men. The number of new cases diagnosed each year is 3 per 1,000 women.
- Toxic multinodular goiter causes 5 percent of the cases of hyperthyroidism in the United States and can be 10 times more common in iodine-deficient areas. It typically occurs in patients older than 40 years with a long-standing goiter, and has a more insidious onset than Graves disease.10 Lymphocytic thyroiditis and postpartum (subacute lymphocytic) thyroiditis are transient inflammatory causes of hyperthyroidism that, in the acute stage…
- Hyperthyroid crisis is rare. It has an incidence of 0.2 cases per 100,000 population and approximately 1-2% of patients with hyperthyroidism progress to a hyperthyroid crisis.
Prognosis
- Long-term implications of treated thyrotoxicosis depend on which of the treatment methods are used, but often result in the need for lifelong medication (thyroid hormone tablets) to be taken daily. Patients on medication should have blood tests taken by their GP at regular intervals to confirm that the dose remains correct. The majority of patients are able to find a medication regime that works well for them and live normal lives. If untreat…
- Agranulocytosis is the most serious complication of antithyroid drug therapy and is estimated to occur in 0.1 to 0.5 percent of patients treated with these drugs.28 The risk is higher in the first several months of therapy and may be higher with PTU than methimazole.5,9,15 It is extremely rare in patients taking less than 30 mg per day of methimazole.9 The onset of agranulocytosis is sometimes abrupt, so patients should be warned to stop taking t…
- 1. Untreated hyperthyroid crisis is usually fatal. 2. Although hyperthyroid storm is rare, it is a critical illness that can lead to multiorgan failure and carries a high death rate. 3. Even with early diagnosis and targeted treatment, the mortality rate of hyperthyroid crisis ranges from 10-30%. 4. It has a fatality rate of 50-90% if left untreated.
- No matter what treatment your dog receives, he will most likely need medication every day for the rest of his life. With treatment, however, many dogs enjoy years of quality life.
Complications
- Hyperthyroidism can lead to a number of complications: 1. Heart problems. Some of the most serious complications of hyperthyroidism involve the heart. These include a rapid heart rate, a heart rhythm disorder called atrial fibrillation that increases your risk of stroke, and congestive heart failure — a condition in which your heart can't circulate enough blood to meet your body's needs. 2. Brittle bones. Untreated hyperthyroidism can als…
- Hyperthyroidism results in high levels of T4 and T3 circulating in the blood. These hormones will speed up metabolism. When this happens, the following symptoms may occur: 1. increased heart rate 2. abnormal heartbeat rhythm (palpitations or \"pounding\") 3. increased body heat, causing one to feel warm even in a cool room 4. moist skin because of perspiration 5. increased activity of nerves, leading to nervousness or slight trem…
Risk Factors
- Risk factors for hyperthyroidism, include: 1. A family history, particularly of Graves' disease 2. Female sex 3. A personal history of certain chronic illnesses, such as type 1 diabetes, pernicious anemia and primary adrenal insufficiency...
Causes
Pathophysiology
- Thyroid hormones affect nearly all of the organs in the body; therefore, thyroid disease often causes secondary problems.
Symptoms
- Clinical Signs Cats afflicted with hyperthyroidism usually develop a variety of signs that may be subtle at first but that become more severe as the disease progresses. The most common clinical signs of hyperthyroidism are weight loss, increased appetite, and increased thirst and urination. Hyperthyroidism may also cause vomiting, diarrhea, and hyperactivity. The coat of affected cats may appear unkempt, matted, or greasy (see Figure 1).
Diagnosis
- Diagnosis A veterinarian who suspects a cat has a thyroid problem will conduct a physical examination and palpate the cats neck area to check for an enlarged thyroid gland (see Figure 2). The cats heart rate and blood pressure may also be checked. If thyroid disease is a possibility, your veterinarian will likely order a blood chemistry panel and an analysis of thyroid hormone levels. Most cats with hyperthyroidism have elevated levels …
Results
- Radioactive iodine therapy is curative within three months of therapy in approximately 95 percent of all hyperthyroid cases. In cases where radioactive iodine therapy is not successful, the treatment can be repeated. Rarely, a permanent reduction in thyroid-hormone levels called hypothyroidism occurs after radioactive iodine treatment. If this is accompanied by clinical signs such as lethargy, obesity, and poor hair coat, then thyroid hor…
Benefits
- Removal of the thyroid glands, called surgical thyroidectomy, is a relatively straightforward surgical procedure that has a good success rate. The advantage of surgery is that it is likely to produce a long-term or permanent cure in most cats, and therefore eliminates the need for long-term medication.
Clinical significance
- Because of the important role the thyroid gland plays in the body, some cats with hyperthyroidism develop secondary problems, including heart disease and high blood pressure. Elevated thyroid hormones stimulate an increased heart rate and a stronger contraction of the heart muscle, and can cause thickening of the left ventricle of the heart over time. If left untreated and unmanaged, these changes may eventually compromise the normal f…
Prognosis
- Hypertension, or high blood pressure, is another potential complication of hyperthyroidism, and can cause additional damage to several organs, including the eyes, kidneys, heart, and brain. If hypertension is diagnosed along with hyperthyroidism, drugs may be needed to control the blood pressure and reduce the risk of damaging other organs. As in the case of heart disease, after the hyperthyroidism has been successfully treated, high bloo…