Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 26-07: Thyroiditis + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Autoimmune thyroiditis (Hashimoto) Most common thyroiditis Antithyroperoxidase or antithyroglobulin antibodies usually high Often progresses to hypothyroidism Painful subacute thyroiditis Hallmark is tender thyroid gland with painful dysphagia Elevated erythrocyte sedimentation rate (ESR) Low antithyroid antibodies distinguish it from autoimmune thyroiditis Infectious thyroiditis Severe, painful thyroid gland Febrile with leukocytosis and elevated ESR Riedel thyroiditis Most often in middle age or older women Usually part of a systemic fibrosing syndrome +++ General Considerations ++ Classification Autoimmune (Hashimoto) thyroiditis (chronic lymphocytic thyroiditis) Most common thyroid disorder in the United States Due to autoimmunity Frequency increased by dietary iodine supplementation Certain drugs can trigger autoimmune thyroiditis: alemtuzumab, amiodarone, interferon-alpha, interleukin-2, ipilimumab, lenalidomide, lithium, thalidomide, tremelimumab, and tyrosine kinase inhibitors Associated with other autoimmune diseases, eg, inflammatory bowel disease, pernicious anemia, Sjögren syndrome, vitiligo, and celiac disease (gluten enteropathy) Rarely associated with other autoimmune conditions such as alopecia areata, hypophysitis, encephalitis, membranous nephropathy myocarditis, or primary pulmonary hypertension Subacute thyroiditis (de Quervain thyroiditis, granulomatous thyroiditis, and giant cell thyroiditis) Relatively common Believed to be caused by viral infection Infectious thyroiditis: rare, caused by pyogenic organisms, usually during systemic infection Postpartum thyroiditis (autoimmune): causes transient hyperthyroidism followed by hypothyroidism Riedel thyroiditis (also known as invasive fibrous thyroiditis, Riedel struma, woody thyroiditis, ligneous thyroiditis, and invasive thyroiditis) Rarest form Usually a manifestation of a multifocal systemic fibrosis syndrome May occur a thyroid manifestation of IgG4-related systemic disease Chronic hepatitis C is associated with an increased risk of autoimmune thyroiditis, with 21% of affected patients having antithyroid antibodies and 13% having hypothyroidism +++ Demographics ++ Autoimmune (Hashimoto) thyroiditis Often familial, varies by kindred and by race Six times more common in women Antithyroid antibodies in US adolescents and adults found in 3% of men and 13% of women 25% of women over age 60 years 14% of whites 11% of Mexican Americans 5% of blacks Subacute thyroiditis accounts for 5% of clinical thyroid disease Riedel thyroiditis usually affects middle-aged or elderly women 40% of women and 20% of men exhibit focal thyroiditis at autopsy + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs +++ Autoimmune (Hashimoto) thyroiditis ++ Thyroid gland usually diffusely enlarged, firm, and finely nodular One lobe may be asymmetrically enlarged, raising concern for neoplasm Neck tightness; pain and tenderness not usually present The thyroid is fibrotic and atrophic in about 10% of cases, particularly in older women Mild dry mouth (xerostomia) or dry eyes (keratoconjunctivitis sicca) related to Sjögren syndrome in ~33% Diplopia due to coexistent myasthenia gravis Manifestations of other autoimmune diseases listed above +++ Painful subacute thyroiditis ++ Acute, usually painful, thyroid enlargement, with dysphagia Pain may radiate to ears Low-grade fever and fatigue If no pain, called "silent thyroiditis" May persist for weeks or months May be associated with malaise +++ Infectious thyroiditis ++ Severe pain, tenderness, redness, and fluctuation in the region of the thyroid gland +++ Riedel thyroiditis ++ Enlargement often asymmetric Gland is stony hard and adherent to neck structures, causing dysphagia, dyspnea, pain, and hoarseness Related conditions include Retroperitoneal fibrosis Fibrosing mediastinitis Sclerosing cervicitis Subretinal fibrosis Sclerosing cholangitis +++ Differential Diagnosis ++ Benign multinodular goiter Iodine-deficient (endemic) goiter Graves disease Thyroid cancer Other malignancies (eg, lymphoma) + Diagnosis Download Section PDF Listen +++ +++ Laboratory Tests ++ Serum thyroid-stimulating hormone (TSH) level is elevated if thyroiditis causes hypothyroidism, suppressed if it causes hyperthyroidism Serum free tetraiodotyronine (T4) level is usually elevated in acute and subacute thyroiditis with hyperthyroidism; normal or low in the chronic forms Autoimmune (Hashimoto) thyroiditis Thyroperoxidase Ab levels increased in 90% Thyroglobulin Ab levels increased in 40% However, some patients with autoimmune thyroiditis have no detectable antithyroid antibodies Thyroid autoantibodies also found in other types of thyroiditis Mildly elevated titers found in 13% of asymptomatic women and 3% of asymptomatic men Only 1% of the population has antibody titers > 1:640 Painful subacute thyroiditis Erythrocyte sedimentation rate markedly elevated Antithyroid antibody titers low +++ Imaging Studies ++ Radioiodine uptake and scan Usually not required Characteristically very low in initial, hyperthyroid phase of subacute thyroiditis, distinguishing thyroiditis from Graves disease Radioiodine uptake may be high with an uneven scan in chronic thyroiditis, with enlargement of the gland, and low in Riedel thyroiditis Ultrasound of thyroid helps distinguish thyroiditis from multinodular goiter or thyroid nodules that are suspicious for malignancy +++ Diagnostic Procedures ++ Ultrasound-guided fine-needle aspiration (FNA) biopsy Indicated for patients with autoimmune (Hashimoto) thyroiditis who have a thyroid nodule Indicated when infectious thyroiditis is suspected; Gram stain and culture should also be obtained Usually not required for subacute thyroiditis but shows characteristic giant multinucleated cells + Treatment Download Section PDF Listen +++ +++ Medications +++ Autoimmune (Hashimoto) thyroiditis ++ Levothyroxine, 0.05–0.2 mg orally daily, if hypothyroidism or large goiter present If euthyroid (normal TSH) and minimal goiter, do not administer levothyroxine but monitor patient until hypothyroidism develops Simvastatin (20 mg orally daily) improved thyroid function over 8 weeks in a small study of patients with autoimmune (Hashimoto) thyroiditis and subclinical hypothyroidism Dietary supplementation with selenium 200 mcg/day reduces serum levels of antithyroperoxidase antibodies In pregnant women, 83 mcg orally daily reduced the usual rebound postpartum increase in antithyroid antibodies without side effects on mother or newborn The long-term effectiveness of statin or selenium therapy on the course of autoimmune (Hashimoto) thyroiditis is unknown +++ Painful subacute thyroiditis ++ Aspirin is the drug of choice, continue for several weeks Propranolol, 10–40 mg every 6 hours orally, for thyrotoxic symptoms Iodinated contrast agents promptly normalize triiodothyronine (T3) levels and dramatically improve thyrotoxic symptoms: ipodate sodium (Oragrafin, Bilivist, Gastrografin) or iopanoic acid (Telepaque), 500 mg once daily orally, until free T4 normalizes Levothyroxine, 0.05–0.1 mg orally daily, if transient hypothyroidism is symptomatic +++ Infectious thyroiditis ++ Antibiotics +++ Riedel thyroiditis ++ Tamoxifen, 20 mg twice daily orally, usually induces partial to complete remissions within 3–6 months and must be continued for years Short-term glucocorticoid treatment for relief of pain and compression symptoms Rituximab may be useful for cases refractory to tamoxifen and glucocorticoids +++ Surgery ++ Infectious thyroiditis requires surgical drainage when fluctuance is marked; thyroidectomy may be required For Riedel thyroiditis, surgery usually fails to permanently alleviate compression and is difficult due to dense fibrous adhesions + Outcome Download Section PDF Listen +++ +++ Follow-Up ++ Euthyroid patients with autoimmune (Hashimoto) thyroiditis must be followed up long-term because hypothyroidism may develop years later +++ Complications ++ Autoimmune (Hashimoto) thyroiditis Hypothyroidism or transient thyrotoxicosis Associated with Other autoimmune disorders Spontaneous miscarriage in first trimester of pregnancy Hyperthyroidism may develop, either due to the emergence of Graves disease or due to the release of stored thyroid hormone Subacute and chronic thyroiditis are complicated by the effects of pressure on the neck structures (eg, dyspnea and, in Riedel struma, vocal cord palsy) Perimenopausal women with high antithyroperoxidase titers are at risk for depression independent of thyroid hormone levels In the infectious forms of thyroiditis, any of the complications of infection may occur Carcinoma or lymphoma may be associated with chronic thyroiditis and must be considered if uneven painless enlargements continue despite treatment +++ Prognosis ++ Autoimmune thyroiditis has an excellent prognosis, because it either remains stable for years or progresses slowly to hypothyroidism, which is easily treated Subacute thyroiditis may smolder for months; spontaneous remissions and exacerbations are common Postpartum thyroiditis usually resolves with return to normal thyroid function; permanent hypothyroidism develops in about 50% of women within 7 years (more commonly in women who are multiparous or who have had a spontaneous abortion) Papillary thyroid carcinoma carries a relatively good prognosis when it occurs in patients with autoimmune (Hashimoto) thyroiditis + References Download Section PDF Listen +++ + +De Leo S et al. Autoimmune thyroid disease during pregnancy. Lancet Diabetes Endocrinol. 2018 Jul;6(7):575–86. [PubMed: 29246752] + +Dhillon-Smith RK et al. Levothyroxine in women with thyroid peroxidase antibodies before conception. N Engl J Med. 2019 Apr 4;380(14):1316–25. [PubMed: 30907987] + +Hu S et al. Multiple nutritional factors and the risk of Hashimoto's thyroiditis. Thyroid. 2017 May;27(5):597–610. [PubMed: 28290237] + +Mantovani G et al. Selenium supplementation in the management of thyroid autoimmunity during pregnancy: results of the "SERENA study", a randomized, double-blind, placebo-controlled trial. Endocrine. 2019 Dec;66(3):542–50. [PubMed: 31129812] + +Nguyen CT et al. Postpartum thyroiditis. Clin Obstet Gynecol. 2019 Jun;62(2):359–64. [PubMed: 30844908] + +Plowden TC et al. Subclinical hypothyroidism and thyroid autoimmunity are not associated with fecundity, pregnancy loss, or live birth. J Clin Endocrinol Metab. 2016 Jun;101(6):2358–65. [PubMed: 27023447] + +Wichman J et al. Selenium supplementation significantly reduces thyroid autoantibody levels in patients with chronic autoimmune thyroiditis: a systematic review and meta-analysis. Thyroid. 2016 Dec;26(12):1681–92. [PubMed: 27702392]