Hashimoto’s Thyroiditis
(Chronic Lymphocytic Thyroiditis or Autoimmune Thyroiditis)

The thyroid gland is a butterfly-shaped gland located in the lower front of the neck. The job of the thyroid gland is to make thyroid hormones. Thyroid hormones are released into the blood and carried to every tissue in the body. Thyroid hormones help the body use energy, stay warm and keep the brain, heart, muscles, and other organs working. In children, thyroid hormone is necessary for normal growth.

• Hashimoto’s thyroiditis often progresses very slowly over many years. You may not have any symptoms early on, even if thyroid antibodies are detected in your blood tests.
• In some cases, the inflammation can cause your thyroid gland to become bigger than normal (goiter), which may cause neck discomfort, pressure or difficulty swallowing.
• Your thyroid gland may become underactive causing your thyroid hormone levels to be low (see Hypothyroidism brochure).

Hypothyroidism can cause symptoms such as:

• feeling tired
• abnormal weight gain
• constipation
• increased sensitivity to cold
• dry skin
• depression
• muscle aches
• difficulty exercising
• irregular or heavy menstrual periods
• Slower increase in height in children

The diagnosis of Hashimoto’s thyroiditis may be made when

• you have symptoms of hypothyroidism, and a blood test shows an underactive thyroid gland [an elevated Thyroid Stimulating Hormone (TSH) level with or without a low thyroid hormone (free T4 or total T4) level].
• you have enlargement of your thyroid gland (goiter).
• you have elevated thyroid antibody levels, if measured.

An ultrasound/sonogram may or may not be needed. However, if done, it can show signs of inflammation, even in early stages when thyroid hormone levels are still normal.

Hashimoto’s thyroiditis can be diagnosed even though you have no symptoms. Your thyroid antibody levels are high, but your thyroid hormone levels are normal. Repeating and monitoring your thyroid antibody levels is not needed. However, you do need to monitor your TSH blood level. Over time, you may develop low thyroid hormone levels.

• If you have high thyroid antibody levels but normal thyroid function tests (TSH and Free T4), you do not require treatment with thyroid hormone.
• If you have only a slightly elevated TSH (mild or subclinical hypothyroidism), you may or may not require medication right away.
  • You may have your TSH level checked once or twice per year to see if you are developing clinical hypothyroidism.
• If you have clinical hypothyroidism (elevated TSH and low thyroid hormone levels), treatment is thyroid hormone replacement with levothyroxine (see Thyroid Hormone Treatment brochure).
  • Levothyroxine is taken by mouth. The dose will be adjusted to the correct level for you based on your TSH level.
  • When levothyroxine is taken in the correct dose, it has no side effects.
    • However, if your dose is too low or you frequently miss doses, you may continue to have symptoms of hypothyroidism and your blood level of TSH will remain elevated. (see Hypothyroidism brochure).
    • If the dose is too high, you may develop symptoms of hyperthyroidism and your TSH blood level will be below normal. (see Hyperthyroidism brochure).
  • Most people with hypothyroidism due to Hashimoto’s thyroiditis will need lifelong treatment with thyroid hormone replacement (levothyroxine).