A Literature Review of Painful Hashimoto Thyroiditis: 70 Published Cases in the Past 70 Years.

Painful Hashimoto thyroiditis (pHT) is a rare diagnosis, and optimal treatment remains unclear. To better characterize pHT, PubMed, Embase, Scopus, and Web of Science indexes were searched for case reports or case series reporting pHT, published between 1951 and February 2019. Seventy cases reported in 24 publications were identified. Female predominance (91.4%) and a median age of 39.00 years (interquartile range, 32.50-49.75 years) were observed. Among reported cases, 50.8% had known thyroid disease (including Hashimoto thyroiditis, Graves disease, and seronegative goiters), 83.3% had positive antithyroid peroxidase antibodies, and 71.2% had antithyroglobulin antibodies. Most cases did not have preceding upper respiratory tract symptoms or leukocytosis. Ultrasound features were consistent with Hashimoto thyroiditis. Thyroid function at initial presentation was hypothyroid (35.9%), euthyroid (28.1%), or thyrotoxic (35.9%). Cases evolved into hypothyroidism (55.3%) and euthyroidism (44.7%), whereas none became hyperthyroid after medical treatment. Thyroid size usually decreased after medical treatment. Most cases were empirically treated as subacute thyroiditis with corticosteroids, levothyroxine, or nonsteroidal anti-inflammatory drugs. However, no therapy provided sustained pain resolution. In subgroup analysis, low-dose oral prednisone (<25 mg/d) and intrathyroidal corticosteroid injection showed more favorable outcomes. Total thyroidectomy yielded 100% sustained pain resolution. Diagnosis of pHT is based on clinical evidence of Hashimoto thyroiditis and recurrent thyroid pain after medical treatment. The reference standard of diagnosis is pathology. Total thyroidectomy or intrathyroidal glucocorticoid injection should be considered if low-dose oral prednisone fails to achieve pain control.