From the Guidelines
The most common subtypes of thyroiditis are Hashimoto's thyroiditis, Graves' disease, and functional thyroid nodules, with Hashimoto's thyroiditis being the most prevalent cause of hypothyroidism in the United States. According to the study published in the Annals of Internal Medicine 1, the most common cause of hypothyroidism in the United States is chronic autoimmune (Hashimoto) thyroiditis. Key points about these subtypes include:
- Hashimoto's thyroiditis is an autoimmune condition where the immune system attacks the thyroid gland, leading to gradual destruction of thyroid tissue and eventual hypothyroidism
- Graves' disease is another common cause of hyperthyroidism, characterized by an overactive thyroid gland producing excess thyroid hormones
- Functional thyroid nodules can also cause hyperthyroidism, although they are less common than Graves' disease and Hashimoto's thyroiditis The study also mentions that risk factors for an elevated TSH level, indicative of hypothyroidism, include female sex, advancing age, white race, type 1 diabetes, Down syndrome, family history of thyroid disease, goiter, previous hyperthyroidism, and external-beam radiation in the head and neck area 1. In terms of treatment, the principal treatment for hypothyroidism is oral T4 monotherapy (levothyroxine sodium), while hyperthyroidism is treated with antithyroid medications or nonreversible thyroid ablation therapy 1. It is essential to note that the optimal screening interval for thyroid dysfunction is unknown, and the USPSTF found no direct evidence that treatment of thyroid dysfunction based on risk level alters final health outcomes 1.
From the Research
Common Subtypes of Thyroiditis
The most common subtypes of thyroiditis include:
- Hashimoto thyroiditis: an autoimmune disorder that presents with or without signs or symptoms of hypothyroidism, often with a painless goiter, and is associated with elevated thyroid peroxidase antibodies 2, 3, 4, 5, 6
- Postpartum thyroiditis: a transient or persistent thyroid dysfunction that occurs within one year of childbirth, miscarriage, or medical abortion 2, 3, 4, 5
- Subacute thyroiditis: a self-limited inflammatory disease characterized by anterior neck pain, suppressed thyroid-stimulating hormone, and low radioactive iodine uptake on thyroid scanning 2, 3, 4, 5
Characteristics of Each Subtype
- Hashimoto thyroiditis: patients typically present with a nontender goiter, hypothyroidism, and an elevated thyroid peroxidase antibody level 2, 6
- Postpartum thyroiditis: release of preformed thyroid hormone into the bloodstream may result in hyperthyroidism, followed by transient or permanent hypothyroidism 2, 3
- Subacute thyroiditis: many cases follow an upper respiratory viral illness, which is thought to trigger an inflammatory destruction of thyroid follicles 2, 3
Treatment and Management
- Hashimoto thyroiditis: treatment with levothyroxine ameliorates the hypothyroidism and may reduce goiter size 2, 6
- Postpartum thyroiditis: beta blockers can treat symptoms in the initial hyperthyroid phase; in the subsequent hypothyroid phase, levothyroxine should be considered in women with a serum thyroid-stimulating hormone level greater than 10 mIU per L, or in women with a thyroid-stimulating hormone level of 4 to 10 mIU per L who are symptomatic or desire fertility 2, 3
- Subacute thyroiditis: treatment with high-dose acetylsalicylic acid or nonsteroidal anti-inflammatory drugs is directed toward relief of thyroid pain 2, 3