Goiters in Dogs

Goiters in dogs are benign conditions in which the thyroid gland enlarges and swells. In general, this condition is typically more alarming to dog owners than it is harmful to dogs. However, goiters in dogs do signal that a medical condition requiring treatment exists, and so it is imperative that dog owners understand what can cause goiters in dogs, as well as how to identify them.

Thyroid Anatomy in Dogs

In order to understand how goiters in dogs can develop, it is essential to understand how the thyroid gland works. They thyroid gland is a butterfly-shaped gland located just anterior to the trachea and towards the base of the neck. The positioning and structure of the thyroid gland actually causes it to wrap around the trachea.

The thyroid gland absorbs iodine and then uses it by converting it into thyroid hormones, thyroxine and triiodothyronine. These hormones are then released to every cell, organ, and structure within the dog’s body to assist with metabolism, cell growth and sustenance. A hormone known as TSH, thyroid stimulating hormone, is released by the pituitary gland in the brain, and this tells the thyroid how much of each hormone to release.

When a dog’s thyroid does not release enough of the crucial thyroid hormones, it is considered underactive and the dog is labeled as hypothyroid. Likewise, excessive release of thyroid hormone is considered overactive, and this is known as hyperthyroidism. Hypothyroidism in dogs is much more common than hyperthyroidism.

Causes of Goiters

The brain and thyroid gland use a complex feedback system to work together and ensure that the proper amount of thyroid hormone is circulating throughout the dog’s body. The brain constantly monitors thyroid hormone production within the thyroid gland. When the brain determines that either too much or too little thyroid hormone is being released, it stimulates the dog’s thyroid to either produce more or produce less.

Over time, consistent stimulation of the dog’s thyroid gland by the brain causes the thyroid cells to multiply, resulting in enlargement of the thyroid gland. Regardless of whether there is too much or too little thyroid hormone, the continuous signaling from the brain eventually causes the multiplication of cells. This swelling of the thyroid gland is recognized as goiter in dogs.  

Goiter Signs and Symptoms

Goiters in dogs generally do not cause any harm, but rather they are signs of an ongoing thyroid dysfunction. However, goiters can grow to be very large in size and can cause a variety of problems for dogs. For this reason, it is imperative that both the goiter and the thyroid condition be treated, so dog owners must be able to recognize the symptoms of goiter in their dog.

Signs and symptoms of goiters in dogs can include:

  • Dysphagia (difficulty swallowing)
  • Dyspnea (shortness of breath at rest)
  • Dyspnea on exertion (shortness of breath during activities)
  • Wheezing sounds on inhalation or exhalation
  • Lack of interest in food
  • Sudden weight loss

In most cases, goiters in dogs will resolve on their own once the condition of the thyroid is treated. However, some dogs suffer from goiters indefinitely. There are surgical options for goiter removal, but it is typically more beneficial to remove the entire thyroid gland in cases of severe goiter in dogs.