Subacute thyroiditis

Subacute thyroiditis (also known as De Quervain’s thyroiditis, granulomatous thyroiditis, or giant cell thyroiditis) is inflammation of the thyroid characterised by a triphasic course of transient thyrotoxicosis, followed by hypothyroidism, followed by a return to euthyroidism. However, the clinical manifestations of all three phases may not be apparent in all individuals.

The thyrotoxic phase is due to thyroid follicular damage and release of preformed thyroid hormone. This phase is characterised by low thyroid uptake on nuclear scan and elevated serum ESR or CRP levels.

Moderate-to-severe neck pain and tenderness, which may be migratory and affect different areas of the thyroid gland at different times, is typical of the thyrotoxic phase. The thyroid is often enlarged, firm, and tender to palpation.

Ultrasound of the thyroid may show areas of hypoechogenicity with decreased or normal vascular flow by Doppler.

The condition is self-limited, and no specific therapy is generally necessary. Non-steroidal anti-inflammatory drugs and beta-blockers may be used for hyperthyroid symptoms during the thyrotoxic phase. Some patients with severe hyperthyroid symptoms may also require corticosteroids, opioid analgesics, or potassium iodide or iopanoic acid to reduce the conversion of T4 to the more biologically active form of thyroid hormone, T3. During the hypothyroid phase, thyroid hormone replacement may help alleviate hypothyroid symptoms if severe.

Subacute thyroiditis (also termed De Quervain’s thyroiditis, granulomatous thyroiditis, or giant cell thyroiditis) is a self-limited inflammation of the thyroid gland. It is associated with a triphasic clinical course, in which each phase may last for a few weeks to many months; the three phases are characterised by transient thyrotoxicosis, hypothyroidism, and then a return to normal thyroid function, with the normal thyroid function occurring in >90% of patients.[1]Nishihara E, Ohye H, Amino N, et al. Clinical characteristics of 852 patients with subacute thyroiditis before treatment. Intern Med. 2008;47(8):725-9. http://www.ncbi.nlm.nih.gov/pubmed/18421188?tool=bestpractice.com [2]Fatourechi V, Aniszewski JP, Fatourechi GZ, et al. Clinical features and outcome of subacute thyroiditis in an incidence cohort: Olmsted county, Minnesota, study. J Clin Endocrinol Metab. 2003 May;88(5):2100-5. http://www.ncbi.nlm.nih.gov/pubmed/12727961?tool=bestpractice.com ​ Only a minority subset will remain permanently hypothyroid and require thyroid hormone replacement. The initial thyrotoxic phase is associated with thyroid pain, high serum thyroid hormone levels, a low radioiodine uptake, elevated circulating ESR and CRP levels, and a systemic illness similar to influenza, with fever, myalgia, and malaise.​​[3]Stasiak M, Lewiński A. New aspects in the pathogenesis and management of subacute thyroiditis. Rev Endocr Metab Disord. 2021 Dec;22(4):1027-39. https://www.doi.org/10.1007/s11154-021-09648-y http://www.ncbi.nlm.nih.gov/pubmed/33950404?tool=bestpractice.com ​​[4]Quintero MB, 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