The term "Thyroiditis" refers to "inflammation of the thyroid gland". There are many possible causes of thyroiditis. Hashimoto's thyroiditis, also referred to as chronic lymphocytic thyroiditis, is the most prevalent cause of hypothyroidism in the United States. It is an autoimmune disorder consisting of chronic inflammation of the thyroid. This condition has a tendency to run in families. Over time, the ability of the thyroid gland to produce thyroid hormones often becomes impaired and results in a gradual decline in function and eventually an underactive thyroid (Hypothyroidism). Hashimoto's thyroiditis occurs most commonly in middle-aged women, but can be seen at any age, and can also affect men and children.
The thyroid gland is a butterfly-shaped endocrine gland that is usually located in the lower front of the neck. The thyroid's job is to make thyroid hormones, which are secreted into the blood and then 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 as they should.
Symptoms
There are no signs or symptoms that are unique to Hashimoto's thyroiditis.
Since the disorder usually progresses very slowly over many years, people with Hashimoto's thyroiditis may not have any symptoms early on, even when the characteristic thyroid peroxidase (TPO) antibodies are found in blood tests. TPO is an enzyme that plays a role in the production of thyroid hormones. If Hashimoto's thyroiditis causes cell damage resulting in low thyroid hormone levels, patients will eventually develop symptoms of hypothyroidism. Hypothyroid symptoms may include fatigue, weight gain, constipation, increased sensitivity to cold, dry skin, depression, muscle aches and lower exercise tolerance, and irregular or heavy menses. In some cases, the inflammation causes the thyroid to become enlarged (goiter), which seldom may cause neck pain or difficulty swallowing.
Diagnosis
The diagnosis of Hashimoto's thyroiditis may be made when individuals present with symptoms of hypothyroidism, often accompanied by a goiter (an enlarged thyroid gland) on physical examination, and laboratory testing of hypothyroidism, which is an elevated thyroid-stimulating hormone (TSH) with or without a low thyroid hormone (Free thyroxine [Free T4] levels. TPO antibodies, when measured, are usually elevated.
Occasionally, the condition may be diagnosed early, especially in individuals with a strong family history of thyroid disease. TPO antibody might be positive, but thyroid hormone levels might be normal or there may only be an isolated mild elevation of serum TSH is seen. Symptoms of hypothyroidism might be missing.
Treatment
Patients with elevated TPO antibodies but regular thyroid function tests (TSH and Free T4) do not need treatment. Individuals with only a slightly elevated TSH (mild hypothyroidism) might not need medication and should have repeat testing after 3-6 months if this has not already been done. For individuals with overt hypothyroidism (elevated TSH and low thyroid hormone levels) treatment consists of thyroid hormone replacement. Synthetic levothyroxine taken by mouth at a suitable dose is inexpensive, very effective in restoring regular thyroid hormone levels, and results in an improvement of symptoms of hypothyroidism. The majority of patients with Hashimoto's thyroiditis will need lifelong treatment with levothyroxine. Identifying the proper dose, especially at the beginning, might require testing with TSH every 6-8 weeks after any dose adjustment, until the right dose is identified. After that, monitoring of TSH once a year is usually enough.
When levothyroxine is taken in the appropriate dose, it has no side effects. However, when an insufficient dose is taken, serum TSH remains raised and patients may have persistent symptoms of hypothyroidism. If the dose is excessive, serum TSH will become suppressed and individuals may develop symptoms of hyperthyroidism or have other side effects.
