What Is Hyperthyroidism?
Hyperthyroidism is the most common glandular disorder in cats. It is most frequently caused by an excessive concentration of circulating thyroxine-a thyroid hormone better known as T4-in the bloodstream.
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Canine Hypothyroidism: How to Spot and Treat This Subtle Disease
Article Found on VetStreet
Although our feline companions can suffer from hyperthyroidism, the majority of dogs with thyroid problems will have the opposite condition — hypothyroidism.
Hypothyroidism occurs when the thyroid glands do not produce enough thyroid hormones. If a dog is hypothyroid, there is a very slim possibility that a tumor is present. However, in most cases, it is simply a dysfunctional thyroid gland. Read more
Thyroid Tumor Surgery in Cats
Article by Dr. Phil Zeltzman | Featured on PetHealthNetwork
Did you know that cats can have a hyperactive thyroid gland? Also known as hyperthyroidism, it’s a fairly common condition in older cats. In fact, the vast majority of affected cats are older than 10 years of age. Most of the time, the reason is either a benign tumor or benign enlargement of the thyroid gland(s). Read more
By Dr. Phil Zeltzman, DVM, DACVS, CVJ | Reviewed by Dr. Peter Kintzer, DVM, DACVIM | Article Featured on PetHealth
AJ Debiasse, a technician in Stroudsburg, PA, contributed to this article.
Did you know that cats can have a hyperactive thyroid gland? Also known as hyperthyroidism, it’s a fairly common condition in older cats. In fact, the vast majority of affected cats are older than 10 years of age. Most of the time, the reason is either a benign tumor or benign enlargement of the thyroid gland(s).
Read more
Did you know that cats can have a hyperactive thyroid gland? Also known as hyperthyroidism, it’s a fairly common condition in older cats. In fact, the vast majority of affected cats are older than 10 years of age. Most of the time, the reason is either a benign tumor or benign enlargement of the thyroid gland(s).
Read more
About Hyperthyroidism In Pets
Excessive secretion of the thyroid hormones, T4 and T3, results in signs that reflect an increased metabolic rate and produces clinical hyperthyroidism. It is most common in middle-aged to old cats but also develops rarely in dogs.
Functional thyroid adenoma (adenomatous hyperplasia) is the most common cause of feline hyperthyroidism; in ~70% of cases, both thyroid lobes are enlarged. Thyroid carcinoma, the primary cause of hyperthyroidism in dogs, is rare in cats (1%–2% of hyperthyroidism cases).
Clinical Findings and Diagnosis
The most common signs include weight loss, increased appetite, hyperexcitability, polydipsia, polyuria, and palpable enlargement of the thyroid gland. GI signs are also common and may include vomiting, diarrhea, and increased fecal volume. Cardiovascular signs include tachycardia, systolic murmurs, dyspnea, cardiomegaly, and congestive heart failure. Rarely, hyperthyroid cats exhibit apathetic signs (eg, anorexia, lethargy, and depression); weight loss remains a common sign in these cats.
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Are Fish Flavored Cat Foods Causing Hyperthyroidism?
Article by Dr. Jennifer Coates | Featured on PetMD
I am all too familiar with hyperthyroidism. It is one of the most common endocrine (hormonal) diseases of cats. I’ve diagnosed many of my patients with the condition, including two of my own cats.
First some background. Hyperthyroidism is a usually caused by a benign tumor within the thyroid gland that secretes large amounts of thyroid hormone. One of the primary functions of this hormone is to regulate an animal’s metabolism. Cats under the influence of too much thyroid hormone have a greatly increased metabolic rate, leading to the classic symptom of weight loss despite a ravenous appetite. Elevated thyroid hormone levels can also lead to high blood pressure, a type of heart disease called hypertrophic cardiomyopathy, vomiting, diarrhea, and increased thirst and urination.
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Flame retardants could contribute to hyperthyroidism in older cats
For years, health advocates have been pushing to ban some flame retardants for their potentially harmful effects, especially on young children and infants. Now scientists report these compounds could play a role in a common health problem for one of our most beloved pets: cats. In the ACS journal Environmental Science & Technology, a new study found that cats with hyperthyroidism had high levels of certain flame retardants, hinting at a possible link.
Jessica Norrgran and colleagues explain that more than 10 percent of older cats develop hyperthyroidism, a hormonal disorder that can cause weight loss, hyperactivity, aggression, vomiting and other symptoms. In humans, the condition has been linked to Graves’ disease and iodine deficiency. No one knows for sure what causes hyperthyroidism in cats. Some studies have suggested a connection between the feline condition and flame retardants. These substances leach from plastics and furniture, and accumulate in dust that can end up on cats’ fur. The animals’ meticulous grooming methods make them particularly susceptible to exposure to these compounds. Norrgran’s team wanted to investigate this potential link further.
The researchers tested blood samples from pet felines in Sweden — 37 hyperthyroid cats and 23 cats with normal thyroid function. They found that those with hyperthyroidism had elevated levels of flame retardants known as polybrominated diphenyl ethers (PBDEs). Although the results don’t prove that the compounds cause the disorder, the study suggests they could be linked.
Source
Oregon Veterinary Specialty Hospital (OVSH) has been serving the Portland and Beaverton area community since 1979. Drs. Steven F. Skinner (Neurology, Neurosurgery) and Robert T. Franklin (Internal medicine.) We welcome referrals from veterinarians all over the Pacific Northwest. Our goal is to help your pet regain health and live a long and happy life.
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Hyperthyroidism In Cats
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The thyroid gland is small and consists of two lobes, one on each side of the trachea (windpipe) in the neck. This gland produces the major thyroid hormone called thyroxine (T4) and a small amount of another hormone, triiodothyronine (T3). These hormones regulate the body’s metabolic rate and affect every system in the body. The production of the thyroid hormones is controlled by the hormone called thyroid stimulating hormone (TSH). TSH is produced by the pituitary gland, which is found at the base of the brain.An interesting article we found on PetMD regarding Raw Food Diets in Dogs and Hyperthyroidism…
Raw Diets and Hyperthyroidism in Dogs
Hyperthyroidism is extremely rare in dogs. It is typically associated with aggressive thyroid tumors that produce large amounts of thyroid hormone. The only other known cause is the ingestion of thyroid hormone from other sources. In each of the last three years, a research study has documented hyperthyroidism in dogs fed raw diets or treats.
What is Hyperthyroidism?
All animals have thyroid glands. The glands are located next to the trachea (wind pipe) just below the larynx (voice box). These glands secrete thyroid hormone. The amount of thyroid hormone in the blood regulates body metabolism. Decreased levels slow metabolism and increased levels speed up metabolism. Heart rate, body temperature, chemical reactions, food utilization, or storage are all dependent on the level of thyroid hormone in the bloodstream.
Animals with hyperthyroidism secrete excess hormone, causing a constant state of metabolic hyperactivity. They often lose weight, have fast heart rates, and ravenous appetites. Side effects also include increased water consumption, increased urination, and vomiting. Long term, this hyper metabolic state can result in heart and kidney failure.
Cat owners are all too familiar with this condition. Over-active, microscopic benign tumors in the thyroid glands are extremely common in older cats. The condition is so common that a veterinary expert in feline hyperthyroidism once quipped, “It seems that every cat is destined to develop hyperthyroidism at some point in its life.”
What is the Cause of Hyperthyroidism in Dogs Fed Raw Food?
Active thyroid hormone secreting tissue is not restricted to the thyroid gland. Research has shown that small, usually microscopic, amounts of active thyroid tissue can be found along the entire trachea, even into the chest. Dogs fed raw animals necks absorb thyroid hormone from attached or residual thyroid gland or thyroid active tissue in the neck. The amount is sufficient to cause symptoms of hyperthyroidism.
In the 2012 and 2013 studies, the diets of the sick dogs were confirmed to have included raw neck tissue or thyroid gland contamination of raw products from a slaughtering plant. The new 2014 study (unpublished) confirmed beef necks and thyroid tissue in raw dog treats. All of the dogs in the studies had elevated thyroid hormone levels without evidence of thyroid tumors. Dietary change resulted in a return to normal blood thyroid levels and relief from the symptoms, suggesting that the raw thyroid tissue was the underlying cause.
Why Hyperthyroidism in Dogs May Become More Common
The popularity of real food raw diets for dogs is becoming extremely popular. Major ingredients in many of these diets are “meaty bones.” Meaty bones are basically the frame (neck, back, and pelvis) of the chicken or small livestock (rabbits), and necks of large livestock after the majority of the choice muscle has been removed. Chicken necks are a very commonly used meaty bone. The combination of residual meat, ligament, tendon. and bone make them attractive for those choosing to feed a diet that more closely mimics the diet of the wild ancestor of the dog. The high bone content is thought to add adequate calcium, phosphorus, and magnesium, and the necks contribute fat and a small amount of protein to the rest of the diet.
These studies suggest that thyroid tissue contamination of raw animal necks or treats containing neck and thyroid tissue can cause hyperthyroidism in dogs. With larger numbers of dogs being fed raw necks we may see more dogs with this condition.
Fortunately, the condition is reversible once thyroid tissue is removed from the diet. Those choosing to feed a raw diet containing meaty bones may want to avoid using necks as part of the diet. Evaluation of blood thyroid hormone levels in dogs on these diets would also be advisable.
Dr. Ken Tudor
Image: V.J. Matthews / Shutterstock
https://www.petmd.com/blogs/thedailyvet/ken-tudor/2014/july/raw-diets-and-hyperthyroidism-dogs-31873#
What You Need to Know About Thyroid Disease in Dogs and Cats
If you’ve been around pets long enough, chances are you’ve known a hypothyroid dog or a hyperthyroid cat. Thyroid gland dysfunction is so common in dogs and cats that I thought a primer was in order.
Where is the Thyroid Gland?
The thyroid gland has two distinct segments, one on each side of the trachea (windpipe) just below the larynx (voice box). In contrast, people have one continuous gland in the shape of a butterfly. In many individuals, some additional small areas of thyroid tissue can be located anywhere from the larynx down to the diaphragm. This “ectopic” tissue can maintain thyroid function after the main gland is surgically removed (e.g., due to cancer).
What Does the Thyroid Gland Do?
The thyroid gland makes several different hormones — mostly thyroxine (T4) but also 3,5,3’-triiodo-thyronine (T3), reverse T3, and a few others. These thyroid hormones have effects throughout the body, for example:
- 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
- skin condition
What are Thyroid Hormone Levels Influenced By?
Many medications can transiently depress (or rarely, elevate) thyroid hormone levels. Blood tests must be carefully evaluated with accurate knowledge of drug therapy. Only one drug is known to have the potential to cause clinical hypothyroidism — trimethoprim-sulfamethoxazole (a sulfa antibiotic medication).
Iodine deficiency can lead to hypothyroidism, although this is rarely clinically significant since commercially prepared dog and cat foods have adequate iodine levels. Goitrogens are substances that interfere with normal thyroid hormone synthesis. Examples include cabbage, broccoli, kale, and rape. Soybean protein in cattle feed is another example, but again dietary issues are rarely a concern for dogs and cats.
Photoperiod (amount of daylight) may be important to thyroid function, but studies are ongoing. Finally, cold temperatures upregulate the thyroid gland leading to increased production of T4 and body heat.
Disease States in Dogs and Cats
Hypothyroidism usually occurs in middle-aged, medium to large breed dogs (rarely in cats). It is usually caused by inflammation or idiopathic atrophy (deterioration of unknown cause) of the thyroid gland and results in decreased production of thyroid hormones. The consequences are multi-factorial due to the many effects of the hormone, but symptoms typically include a low energy level, weight gain, a tendency to seek out warm places in the home, a poor quality coat, and recurrent skin and ear problems. Treatment consists of replacement thyroid hormone given orally.
Hyperthyroidism occurs much more often in cats. Feline hyperthyroidism is almost always due to a benign tumor in the thyroid gland. The tumor stimulates the gland to produce too much hormone and causes an upregulation in metabolism, with resulting weight loss despite a good or even ravenous appetite, increased energy levels, and possibly heart disease. The gold standard therapy is radioactive iodine (I131) treatment, which is curative in most cases. Medication (methimazole) or dietary therapy using a food with a reduced iodine content are good options when I131 therapy is not appropriate due to financial considerations or the cat’s overall health.
Dr. Jennifer Coates
https://www.petmd.com/blogs/thedailyvet/dr-coates/2014/june/what-you-need-know-about-thyroid-disease-dogs-and-cats-31743?icn=HP-HEALTH&icl=What%20You%20Need%20to%20Know%20About%20Thyroid%20Disease%20in%20Dogs%20and%20Cats