Hyperthyroidism In Dogs: Symptoms, Causes, And Treatments

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Hyperthyroidism in dogs is a condition that is caused by the thyroid gland in the neck overproducing thyroxine, a hormone that controls metabolism. Metabolism is important because it is the process of converting food into fuel for a dog’s organs and entire body. Hyperthyroidism is rarer in dogs than hypothyroidism, and it usually results from an aggressive thyroid tumor. It can cause a number of symptoms in canines that range from frequent urination and diarrhea to heart and kidney failure if left untreated. If you spot the signs of hyperthyroidism, it is important to get to your veterinarian right away. Here is what you should know about the symptoms, causes, and treatments of hyperthyroidism in dogs.

Symptoms Of Hyperthyroidism In Dogs

Podenco Canario (In English: Canary Islands Hound, Canarian Warren Hound) is a breed of dog originally from the Canary Islands. The Podenco Canario is still used in the Canary Islands today in packs as a hunting dog, primarily used for rabbit hunting. The word "podenco" is Spanish for "hound". "Canario" means "Canarian" or "of the Canaries".

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The symptoms of hyperthyroidism in dogs result from an increase in metabolism that send the body into overdrive. Because of this, there may be irregularities in all of the body’s systems. Most commonly, the condition results in weight loss, despite an increase in appetite. Here are a few symptoms you might see in dogs with hyperthyroidism.

  • Excessive weight loss
  • Increased appetite
  • Frequent urination and increased thirst
  • Vomiting
  • Diarrhea
  • Depression
  • Weakness
  • Excitability
  • Enlarged thyroid gland, felt as a lump in the neck
  • Difficulty breathing
  • Irregular heart beat

Causes Of Hyperthyroidism In Dogs

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Hyperthyroidism is usually caused by an excessive production of thyroxine brought on by aggressive thyroid cancer. The tumor interferes with the normal functions of the thyroid, resulting in secretion of certain hormones, affecting metabolism and resulting in visible symptoms.

An excess of thyroid hormones doesn’t necessarily have to originate in a dog’s thyroid. Another source of thyroid hormones is from hypothyroid medication, which usually includes a synthetic form of thyroxine. An over-correction of low thyroxine levels can sometimes result in hyperthyroidism.

Additionally, raw food diets that include an excessive amount of thyroid hormones can also cause the condition. These diets often include gullets, head meat, and animal necks, which contain higher levels of thyroid hormones. Varying a dog’s protein source or avoiding these animal parts can prevent a dog from ingesting too many of these hormones.

Treatments Of Hyperthyroidism In Dogs

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Treatment of hyperthyroidism in dogs depends on the cause of the condition. In cases where it is caused by a reaction to medication for hypothyroidism, usually the dosage of drugs can be adjusted until the hormone levels are stable. If hyperthyroidism results from a diet that contains high levels of hormones, a dietary change is usually sufficient to reverse the condition.

Unfortunately, it is more common for hyperthyroidism to result from aggressive thyroid cancer, which is often deadly. Treatment in this case will depend on the size of the tumor and whether it has metastasized. Treatment may entail partial removal of the tumor or removal of the entire thyroid gland. This will depend on what your veterinarian deems the most appropriate course to pursue.

Additionally, radiation therapy and chemotherapy are other options to fight the cancer, and are at times used alongside surgery. Benign tumors are easier to manage and may respond well to treatment, but malignant tumors can often spread to vital organs in the neck. The earlier treatment begins, the better the chance at recovery. In cases where dogs recover, dietary restrictions will have to be strictly followed, especially to preserve the health of the kidneys.

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