Acute and Subacute Thyroiditis
The term thyroiditis refers to inflammation of the thyroid gland, which has many causes. The tempo of clinical presentation is used to classify thyroiditis into acute, subacute, and chronic types, but in practice there is considerable overlap. Acute forms of thyroiditis include acute infectious thyroiditis caused by bacterial or fungal infection (most commonly arising from a piriform sinus tract fistula or hematogenous spread) and radiation-induced and traumatic thyroiditis. Many types of thyroiditis may present in a subacute fashion, but the term subacute thyroiditis is generally reserved for a specific type of thyroiditis characterized pathologically by granulomatous inflammation and the presence of giant cells, which is thought to be precipitated by viral infection in genetically predisposed individuals. Acute infectious thyroiditis and subacute thyroiditis each present with painful anterior neck swelling and constitutional symptoms; careful clinical assessment, supported by judicious use of imaging and fine-needle aspiration biopsy, allows diagnostic differentiation. Thyroid dysfunction in subacute thyroiditis classically follows a triphasic course of hyperthyroidism, followed by hypothyroidism and eventual resolution to euthyroidism, but these phases are not all observed in all patients. In hyperthyroid patients, it can be difficult to distinguish clinically between subacute thyroiditis, lymphocytic thyroiditis, and Graves’ disease, and inflammatory markers, thyroid antibody measurement, and radionuclide imaging can be diagnostically helpful. The treatment of acute infectious thyroiditis is with systemic antimicrobial treatment and surgical drainage. For subacute thyroiditis, treatment is not always required; when it is warranted, nonsteroidal anti-inflammatory drugs or glucocorticoid treatment can be offered for the painful thyroiditis and beta-blockade for symptoms of thyrotoxicosis. Follow-up of thyroid function is recommended to ensure resolution.
KeywordsThyroiditis Acute thyroiditis Infectious thyroiditis Piriform sinus tract fistula Radiation thyroiditis Traumatic thyroiditis Subacute thyroiditis De Quervain’s thyroiditis Subacute granulomatous thyroiditis
- Amino N, Yabu Y, Miki T, Morimoto S, Kumahara Y, Mori H, Iwatani Y, Nishi K, Nakatani K, Miyai K. Serum ratio of triiodothyronine to thyroxine, and thyroxine-binding globulin and calcitonin concentrations in Graves’ disease and destruction-induced thyrotoxicosis. J Clin Endocrinol Metab. 1981;53(1):113–6.CrossRefPubMedGoogle Scholar
- Bahn RS, Burch HB, Cooper DS, Garber JR, Greenlee MC, Klein I, Laurberg P, McDougall IR, Montori VM, Rivkees SA, Ross DS, Sosa JA, Stan MN. Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Endocr Pract. 2011;17(3):456–520.CrossRefPubMedGoogle Scholar
- Cherk MH, Kalff V, Yap KS, Bailey M, Topliss D, Kelly MJ. Incidence of radiation thyroiditis and thyroid remnant ablation success rates following 1110 MBq (30 mCi) and 3700 MBq (100 mCi) post-surgical 131I ablation therapy for differentiated thyroid carcinoma. Clin Endocrinol (Oxf). 2008;69(6):957–62.CrossRefGoogle Scholar
- Erdem N, Erdogan M, Ozbek M, Karadeniz M, Cetinkalp S, Ozgen AG, Saygili F, Yilmaz C, Tuzun M, Kabalak T. Demographic and clinical features of patients with subacute thyroiditis: results of 169 patients from a single university center in Turkey. J Endocrinol Invest. 2007;30(7):546–50.CrossRefPubMedGoogle Scholar
- Mori K, Yoshida K, Funato T, Ishii T, Nomura T, Fukuzawa H, Sayama N, Hori H, Ito S, Sasaki T. Failure in detection of Epstein-Barr virus and cytomegalovirus in specimen obtained by fine needle aspiration biopsy of thyroid in patients with subacute thyroiditis. Tohoku J Exp Med. 1998;186(1):13–7.CrossRefPubMedGoogle Scholar