Painless lymphocytic thyroiditis

Painless lymphocytic thyroiditis, known more simply as painless thyroiditis or silent thyroiditis, is an autoimmune-mediated inflammation of the thyroid gland causing release of thyroid hormones and transient thyrotoxicosis. This is frequently followed by a hypothyroid phase before recovery of normal thyroid function. However, for some patients, hypothyroidism is permanent.

Thyroiditis may occur sporadically, postnatally, during drug treatment or radiation therapy, or as the result of bacterial or viral infection.

The diagnosis can be confirmed by a 4-, 6-, or 24-hour radioiodine uptake of <1% during the hyperthyroid phase of the illness.

Treatment, if needed, includes beta-blockers for the hyperthyroid phase and levothyroxine for the hypothyroid phase of the illness.

Painless lymphocytic thyroiditis, known more simply as painless thyroiditis or silent thyroiditis, is characterised by an autoimmune-mediated lymphocytic inflammation of the thyroid gland resulting in a destructive thyroiditis with release of thyroid hormone and transient thyrotoxicosis (hyperthyroidism).[1]Pearce EN, Farwell AP, Braverman LE. Thyroiditis. N Engl J Med. 2003 Jun 26;348(26):2646-55. http://www.ncbi.nlm.nih.gov/pubmed/12826640?tool=bestpractice.com [2]Woolf PD. Transient painless thyroiditis with hyperthyroidism: a variant of lymphocytic thyroiditis? Endocr Rev. 1980 Fall;1(4):411-20. http://www.ncbi.nlm.nih.gov/pubmed/7018893?tool=bestpractice.com [3]Samuels MH. Subacute, silent and postpartum thyroiditis. Med Clin North Am. 2012 Mar;96(2):223-33. http://www.ncbi.nlm.nih.gov/pubmed/22443972?tool=bestpractice.com This is frequently followed by a hypothyroid phase  before recovery of normal thyroid function.

Painless thyroiditis is part of the spectrum of autoimmune thyroid disease and is considered by many to be a variant presentation of Hashimoto's thyroiditis (also known as chronic lymphocytic or chronic autoimmune thyroiditis). This is because individuals with painless thyroiditis may progress to permanent hypothyroidism, which is a characteristic feature of Hashimoto’s thyroiditis.[2]Woolf PD. Transient painless thyroiditis with hyperthyroidism: a variant of lymphocytic thyroiditis? Endocr Rev. 1980 Fall;1(4):411-20. http://www.ncbi.nlm.nih.gov/pubmed/7018893?tool=bestpractice.com [3]Samuels MH. Subacute, silent and postpartum thyroiditis. Med Clin North Am. 2012 Mar;96(2):223-33. http://www.ncbi.nlm.nih.gov/pubmed/22443972?tool=bestpractice.com [4]Nikolai TF, Brousseau J, Kettrick MA, et al. Lymphocytic thyroiditis with spontaneously resolving hyperthyroidism (silent thyroiditis). Arch Intern Med. 1980 Apr;140(4):478-82. http://www.ncbi.nlm.nih.gov/pubmed/6892676?tool=bestpractice.com Other types of autoimmune thyroid disease include Graves’ disease and postnatal thyroiditis.[5]Martinez Quintero B, Yazbeck C, Sweeney LB. Thyroiditis: Evaluation and Treatment. Am Fam Physician. 2021 Dec 1;104(6):609-17 http://www.ncbi.nlm.nih.gov/pubmed/34913664?tool=bestpractice.com

This topic covers painless thyroiditis only. Please see below for other related topics:

• Graves’ disease

• Subacute granulomatous thyroiditis

• Primary hypothyroidism

• Central hypothyroidism

• Overview of thyroid dysfunction

• Thyroid function testing