Thyroid Disease in Canines
Generally, low thyroid hormone levels (i.e. hypothyroidism) can occur in dogs between 2 -6 years old, but this can vary, and its onset may not even be noticed right away by the pet owner. The thyroid gland plays a key role in regulating metabolism, so loss of thyroid hormones will cause a slowdown in cellular metabolism. Properly identified and treated hypothyroidism will not shorten your Welsh Springer Spaniel's lifespan, and it is a very manageable disorder. Two types of hypothyroidism can affect Welsh Springer Spaniels.
Signs of hypothyroidism are gradual in onset and may be so subtle that owners may not notice them until the dog is quite symptomatic. The list includes lethargy, listlessness, or drowsiness; mental depression; exercise intolerance; weight gain; personality change; seeking out warm places; and infertility in some breeding animals. Additional symptoms include hair loss on the tail and along the trunk or body, resulting in a "rat tail" appearance; dry or oily skin associated with darkened skin; and thickening of the skin. The dog can develop a decreased heart rate, and there may be neurological signs such as seizures; stumbling; circling; dragging the feet so that the top part of the nails wear down; and front leg lameness.
Testing for hypothyroidism includes the following studies:
Treating primary hypothyroidism is relatively easy and inexpensive, but it will require lifetime administration of thyroxine twice dailly, and periodic monitoring with blood tests to assure adequate therapeutic levels are maintained. If the hypothyroidism is due to Auto-Immune Thyroiditis, this is considered a hereditary disorder. For this reason, you should discuss thyroid testing status of the parents of any puppy you are interested in acquiring.
Treatment of secondary hypothyroidism caused by pituitary gland involvement has a more guarded outcome, and other endocrine functions may need to be managed because of the complex nature of the pituitary gland. For example, dogs with Cushings Disease (over-production of cortisol) due to a pituitary tumor may also become hypothyroid, and will require treatment for both conditions to maintain their quality of life.
- Primary or acquired hypothyroidism, which is the most common form of this disorder.
- Secondary hypothyroidism, which is caused by destruction or malfunction of the pituitary gland in the brainstem.
Signs of hypothyroidism are gradual in onset and may be so subtle that owners may not notice them until the dog is quite symptomatic. The list includes lethargy, listlessness, or drowsiness; mental depression; exercise intolerance; weight gain; personality change; seeking out warm places; and infertility in some breeding animals. Additional symptoms include hair loss on the tail and along the trunk or body, resulting in a "rat tail" appearance; dry or oily skin associated with darkened skin; and thickening of the skin. The dog can develop a decreased heart rate, and there may be neurological signs such as seizures; stumbling; circling; dragging the feet so that the top part of the nails wear down; and front leg lameness.
Testing for hypothyroidism includes the following studies:
- Free Thyroxine (FT4)
- Canine Thyroid Stimulating Hormone (TSH)
- Thyroglobulin Autoantibody (TgAA)
Treating primary hypothyroidism is relatively easy and inexpensive, but it will require lifetime administration of thyroxine twice dailly, and periodic monitoring with blood tests to assure adequate therapeutic levels are maintained. If the hypothyroidism is due to Auto-Immune Thyroiditis, this is considered a hereditary disorder. For this reason, you should discuss thyroid testing status of the parents of any puppy you are interested in acquiring.
Treatment of secondary hypothyroidism caused by pituitary gland involvement has a more guarded outcome, and other endocrine functions may need to be managed because of the complex nature of the pituitary gland. For example, dogs with Cushings Disease (over-production of cortisol) due to a pituitary tumor may also become hypothyroid, and will require treatment for both conditions to maintain their quality of life.