Hyperthyroidism symptoms in dogs

The thyroid gland is an endocrine gland. It is one of the glands that secretes hormones that help the body function. The thyroid gland gives off thyroxine, a hormone that regulates the metabolism, growth and development of the body. When the thyroid does not produce enough hormone, the condition is called hypothyroidism. When the thyroid gland produces too much thyroxine, it is called hyperthyroidism.


Hyperthyroidism is rare in dogs. Most dogs with thyroid problems have too little thyroxine. Very few dogs are diagnosed with hyperthyroidism. It is usually caused by cancer of the thyroid gland. The cancer tumour causes the thyroid to give off too much hormone. This disease usually affects older dogs.


When a dog has too much thyroxine, it may lose weight even though it is eating the same amount of food. It may be hungry all the time and bolt its food until it vomits. The dog is often excessively thirsty. It can have diarrhoea and urinate much more often than normal.


A dog with hyperthyroidism often is irritable and hyperactive because of the excess hormones. Its coat may look shaggy. Weight loss often causes the dog to be too thin and suffer muscle wasting. Though it is overly active at times, the dog may be weak due to the loss of muscle strength and its nervous physical activity.


A dog may develop the appearance of hyperthyroidism because of treatment for hypothyroidism. In hypothyroidism, the dog is often prescribed thyroxine medication, because the thyroid gland is atrophied or not giving enough natural hormone. The prescription medication may be at too high a dose and cause the dog to have symptoms of hyperthyroidism even though it is suffering from the opposite condition.


When a blood test or other evaluations indicate hyperthyroidism, a veterinarian may recommend prescription medication that controls the excess hormone production. Blood tests are given at intervals to be sure the dog has the correct hormone level. Sometimes surgical removal of the cancer-stricken thyroid gland is recommended. After the surgery, the dog needs thyroxine to replace the lost hormones. A third treatment is the use of radioactive iodine to kill the excess thyroid cells.


Dogs that develop hyperthyroidism are usually older dogs. Aged dogs often do not tolerate treatment options equally. A veterinary evaluation helps the dog owner make the right decision for treatment. Hyperthyroidism can be fatal, and a dog owner may decide to follow the option offering the most comfort and least life disruption for the dog. Homeopathic remedies such as herbs may have a calming effect on the excitable dog and ease thyroid overactivity. A combination of traditional and homeopathic treatment may offer the most canine comfort and benefit.

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About the Author

Phyllis Benson is a professional writer and creative artist. Her 25-year background includes work as an editor, syndicated reporter and feature writer for publications including "Journal Plus," "McClatchy Newspapers" and "Sacramento Union." Benson earned her Bachelor of Science degree at California Polytechnic University.