Hypothyroidism is diagnosed with blood tests. Many dogs have a low "resting" thyroid hormone (T4) level in their blood stream. If the resting T4 is normal, but hypothyroidism is still suspected, a TSH stimulation test can be run. The TSH stimulation test evaluates how well the thyroid gland responds to TSH (Thyroid Stimulating Hormone). Hypothyroid dogs do not respond normally.
Hypothyroid dogs are easily treated with thyroid pills. Thyroid pills are inexpensive but must be continued daily for the rest of the petıs life. They replace the hormone the thyroid gland does not make, but do not cure the underlying gland malfunction. The lethargy and depression usually responds to pills within 2-4 weeks but skin and coat problems may take 5 months for correction. One note of warningthe coat may look worse before it improves as the old coat is shed prior to growing a healthy one.
Each dog's thyroid replacement needs is individual and can change over it's lifetime so periodic blood tests to check hormone levels are recommended, the first one about one month after the start of treatment. Schedule blood tests 4-8 hours after the pill is given to get the proper hormone levels.