Chronic thyroiditis is an inflammation of the thyroid gland that frequently results in hypothyroidism (lowered thyroid function).

Chronic thyroiditis or Hashimoto's disease is a common thyroid gland disorder that can occur at any age, but it is most often seen in middle aged women. It is caused by a reaction of the immune system against the thyroid gland.

The onset of the disease is slow, and it may take months or even years for the condition to be detected. Chronic thyroiditis is most common in women and individuals with a family history of thyroid disease. It is estimated to affect between 0.1% and 5% of all adults in Western countries.

Hashimoto's disease may rarely be associated with other endocrine disorders caused by the immune system. When Hashimoto's disease occurs with adrenal insufficiency and type 1 diabetes, the condition is called type 2 polyglandular autoimmune syndrome (PGA II).

Less commonly, Hashimoto's disease occurs with hypoparathyroidism, adrenal insufficiency, and fungal infections of the mouth and nails in a condition called type 1 polyglandular autoimmune syndrome (PGA I).

• Intolerance to cold
• Weight gain - mild
• Fatigue
• Constipation
• Enlarged neck or presence of goiter
• Small or atrophic thyroid gland (late in the disease)
• Dry skin
• Hair loss
• Heavy and irregular menses
• Difficulty concentrating or thinking

Additional symptoms that may be associated with this disease:

• Weight gain (unintentional)
• Joint stiffness
• Facial swelling

Note: There may be no symptoms.

Laboratory tests to determine thyroid function include:

• Free T4 test (low)
• Serum TSH (high)
• T3 (low or normal)
• Thyroid autoantibodies are frequently present:
  • antithyroid peroxidase antibody
  • antithyroglobulin antibody

This disease may also alter the results of the following tests:

• Radioactive iodine uptake
• Complete blood count
• Total cholesterol
• Serum sodium
• Serum prolactin

A deficiency of thyroid hormone may develop at a later time. Replacement therapy with thyroid hormone (levothyroxine) is given if the hormone is deficient or may be given if there is evidence of mild thyroid failure (such as elevated TSH), also known as subclinical hypothyroidism. If there is no evidence of thyroid hormone deficiency, treatment may be limited to regular observation by a health care provider.

The outcome is usually very good because the disease remains stable for years or progresses slowly to a condition of thyroid hormone deficiency (hypothyroidism) that can be treated with thyroid replacement therapy.

• can be associated with other autoimmune disorders

Call your health care provider if symptoms of chronic thyroiditis develop.

There is no known way to prevent this disorder. Awareness of risk factors may allow earlier diagnosis and treatment.