Hashimoto’s (Lymphocytic) Thyroiditis
The thyroid gland is a butterfly-shaped endocrine gland that is normally 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. The thyroid gland makes two thyroid hormones, triiodothyronine (T3) and thyroxine (T4). Thyroid hormones help the body use energy, stay warm and keep the brain, heart, muscles, and other organs working as they should.
Thyroid hormone production is regulated by another hormone called thyroid-stimulating hormone (TSH). TSH is made by the pituitary gland, a pea-sized gland located in the brain. When thyroid hormone levels in the blood are low, the pituitary releases more TSH. When thyroid hormone levels are high, the pituitary responds by dropping TSH production.
What is Hashimoto’s thyroiditis?
Hashimoto’s thyroiditis (also called autoimmune or chronic lymphocytic thyroiditis) is the most common thyroid disease in the United States. It is an inherited condition that affects approximately 14 million Americans and is about 7 times more common in women than in men. Hashimoto’s thyroiditis is characterized by the production of immune cells and auto anti bodies by the body’s immune system, which can damage thyroid cells and compromise their ability to make thyroid hormone. Hypothyroidism occurs if the amount of thyroid hormone which can be produced is not enough for the body’s needs. The thyroid gland may also enlarge in some patients, forming a goiter
What is the cause of Hashimoto’s thyroiditis?
Hashimoto’s thyroiditis results from a malfunction in the immune system. When working properly, the immune system is designed to protect the body against invaders, such as bacteria, viruses, and other foreign substances. The immune system of someone with Hashimoto’s thyroiditis mistakenly recognizes normal thyroid cells as foreign tissue, and it produces antibodies that may destroy these cells. Although various environmental factors have been studied, none have been positively proven to be the cause of Hashimoto’s thyroiditis.
What are the symptoms of Hashimoto’s thyroiditis?
Many people with Hashimoto’s thyroiditis have no symptoms at first. As the disease slowly progresses, the thyroid usually enlarges and may cause the front of the neck to look swollen. The enlarged gland, called a goiter, may create a feeling of fullness in the throat but is usually not painful. After years, or even decades, the damage to the thyroid causes it to shrink and the goiter to disappear.
Not everyone with Hashimoto’s thyroiditis develops hypothyroidism. For those who do, the hypothyroidism may be subclinical—mild and without symptoms. Other people have one or more of these common symptoms of hypothyroidism:
• Weight gain
• Cold intolerance
• Joint and muscle pain
• Dry, thinning hair
• Heavy or irregular menstrual periods and impaired fertility
• A slowed heart rate
The thyroid enlargement and/or hypothyroidism caused by Hashimoto’s thyroiditis tends to progress in many patients, causing a slow worsening of symptoms. Therefore, patients with either of these findings should be recognized and adequately treated with thyroid hormone. Optimal treatment with thyroid hormone will eliminate any symptoms due to thyroid hormone deficiency, usually prevent further thyroid enlargement, and may sometimes cause shrinkage of an enlarged thyroid gland.
How is Hashimoto’s thyroiditis diagnosed?
The diagnosis of Hashimoto’s thyroiditis may be made when patients 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 antibody, when measured, is usually elevated.
Occasionally, the disease may be diagnosed early, especially in people with a strong family history of thyroid disease. TPO antibody may be positive, but thyroid hormone levels may be normal or there may only be isolated mild elevation of serum TSH is seen. Symptoms of hypothyroidism may be absent.
How is Hashimoto’s thyroiditis treated?
Treatment generally depends on whether the thyroid is damaged enough to cause hypothyroidism. In the absence of hypothyroidism, some doctors treat Hashimoto’s thyroiditis to reduce the size of the goiter. Others choose not to treat the disease and simply monitor their patients for disease progression.
Hashimoto’s thyroiditis, with or without hypothyroidism, is treated with synthetic thyroid hormone. Doctors prefer to use synthetic T4 such as Synthroid rather than synthetic T3 because T4 stays in the body longer, ensuring a steady supply of thyroid hormone throughout the day. The so-called “natural” thyroid preparations made with desiccated animal thyroid are rarely prescribed today.
The exact dose of synthetic thyroid hormone depends on a person’s age and weight; the severity of the hypothyroidism, if present; the presence of other health problems; and the use of other medications such as cholesterol-lowering drugs that could interfere with the action of synthetic thyroid hormone.
Doctors routinely test the blood of patients taking synthetic thyroid hormone and make dosage adjustments as necessary. A normal, healthy thyroid and metabolic state can be restored with the use of synthetic thyroid hormone.