Subacute Thyroiditis – literature overview and COVID-19

Subacute thyroiditis (SAT), also known as de Quervain’s thyroiditis, is a rare thyroid gland disorder, although it is the most common type of painful thyroiditis. The incidence of this disorder is relatively low but likely to be underestimated. Epidemiological studies vary, estimating a prevalence of 12/100,000/year and patients with SAT constitute less than 5% of all patient consultations due to thyroid disease. For the reason, that SAT can present with a variety of symptoms to different specialists. This review summarises current knowledge of SAT with an emphasis on reports related to SARS-CoV-2.

MON-468 Hypoechoic Nodule Is Not Always the Bad Guy: Lessons Learned from a Patient with Subacute Painful Thyroiditis

Introduction: The diagnosis of subacute painful thyroiditis (SAT) is primarily based on clinical manifestations (thyroid tenderness and diffuse goiter). Suppressed TSH, elevated erythrocyte sedimentation rate (ESR) and low thyroid uptake help confirm the diagnosis. Thyroid ultrasonography and fine-needle aspiration biopsy (FNAB) are rarely necessitated. SAT produces a typical sonographic findings of ill-defined heterogeneously hypoechoic areas, which is difficult to differentiate from thyroid carcinoma. We herein report a patient with SAT who was initially diagnosed as malignancy. Case Presentation: A 36-year-old female had pain and swelling at the left thyroid gland for 3 weeks. A left thyroid nodule was diagnosed by her primary care physician. Ultrasonography revealed a poorly defined hypoechoic nodule measuring 2.5x1.1x1.5 cm at the mid pole of the left thyroid gland, for which biopsy was recommended. The nodule showed peripheral vascularity and no calcification. No suspicious cervical lymphadenopathy was detected. Histologic analysis from core biopsy found findings consistency with follicular neoplasm. Thyroid function tests were within normal range. She was treated with ibuprofen as management of thyroid pain and referred for surgery. However, the repeated ultrasonography was performed by endocrinologist in the next 2 weeks and found an interval reduction in size of hypoechoic lesion. FNAB was performed due to the risk of infiltrative malignancies. Cytologic analysis was compatible with SAT. ESR was slightly elevated. Surgery was cancelled and she was treated with ibuprofen. Two weeks later, she reported that the left thyroid pain and swelling had subsided. However, she developed thyroid pain associated with glandular tenderness and swelling of the right thyroid. On sonographic examination, the right lobe, which was previously normal was now similarly affected. Thyroid function showed thyrotoxicosis. The patient was given a further course of beta-blocker, ibuprofen and prednisolone for 2 weeks and recovered well. On follow-up at 2 months, the patient developed biochemical hypothyroidism and received levothyroxine replacement. The lesions in the thyroid gland were not visualized in the 6-month follow-up sonography. Conclusion: The ultrasonographic features of the thyroid during the acute stage of SAT may mimic thyroid carcinoma. Awareness of the sonographic findings and interval changes of SAT lesions may helpful for proper diagnosis and treatment of SAT.

Management

Treatment of Hashimoto thyroiditis (HT) is mainly medical supplementing L-thyroxine (L-T4) for hypothyroidism. L-thyroxine has proved to reduce the volume of the thyroid gland in both hypothyroidism and euthyroid state. The dose of L-T4 is tailored according to the patient's needs; the standard dosage is 1.6-1.8 µ/kg/day. The level of TSH is frequently monitored for dose adjustment till euthyroid state is attained thereafter every 6-12 months. Thyroidectomy is considered in patients with cosmetic problem; with compressive symptoms (such as dysphagia, dyspnea, change of voice), suspicion of malignancy as papillary thyroid carcinoma is commonly associated. Surgery has a beneficial effect in cases of painful thyroiditis. Radioactive iodine treatment can be considered as a last option in elderly patients with large goiter who refuse surgery and their thyroiditis is not responding to L-T4 treatment. This chapter explores the management of Hashimoto's disease.

Lugol's solution-induced painless thyroiditis

Summary Lugol’s solution is usually employed for a limited period for thyroidectomy preparation in patients with Graves’ disease and for the control of severe thyrotoxicosis and thyroid storm. We describe a rare case of Lugol’s solution-induced painless thyroiditis. In November 2014, a 59-year-old woman was prescribed Lugol’s solution four drops per day for the alleviation of menopausal symptoms. She was referred to our clinic in June 2015 for fatigue, hair loss, and a 20-lb weight loss without thyroid pain or discomfort. Physical examination revealed a normal thyroid gland. On 7 May 2015, laboratory tests revealed a suppressed thyroid-stimulating hormone (TSH) 0.01 U/L with elevated free T4 3.31 ng/dL (42.54 pmol/L). Repeat testing on 25 May 2015 showed spontaneous normalization of the free thyroid hormone levels with persistently low TSH 0.10 U/L. Following these results, a family physician prescribed methimazole 10 mg PO TID and very soon after, the TSH concentration rose to >100 U/L along with subnormal free T4 and T3 levels. Methimazole was promptly discontinued, namely within 18 days of its initiation. Over the course of the next few months, the patient spontaneously achieved clinical and biochemical euthyroidism. To our knowledge, this is a unique case of painless thyroiditis induced by Lugol’s solution, which has not been reported before. Lugol’s solution is a short-term medication given for the preparation of thyroidectomy in patients with Graves’ disease and for the control of severe thyrotoxicosis. Iodine excess can cause both hyperthyroidism and hypothyroidism. Rarely, Lugol’s solution can cause acute painless thyroiditis. Learning points: Lugol’s solution is used for thyroidectomy preparation in patients with Graves’ disease and for the control of severe thyrotoxicosis and thyroid storm. Iodine excess can cause both hypothyroidism and thyrotoxicosis. Thyroid glands with an underlying pathology are particularly susceptible to the adverse effect of iodine. The prolonged off-label use of Lugol’s solution can be harmful. Rarely, Lugol’s solution can cause acute painful thyroiditis.

Thyroidectomy for Painful Thyroiditis Resistant to Steroid Treatment: Three New Cases with Review of the Literature

Thyroidal pain is usually due to subacute thyroiditis (SAT). In more severe forms prednisone doses up to 40 mg daily for 2-3 weeks are recommended. Recurrences occur rarely and restoration of steroid treatment cures the disease. Rarely, patients with Hashimoto’s thyroiditis (HT) have thyroidal pain (painful HT, PHT). Differently from SAT, occasional PHT patients showed no benefit from medical treatment so that thyroidectomy was necessary. We report three patients who did not show clinical response to prolonged high dose prednisone treatment: a 50-year-old man, a 35-year-old woman, and a 33-year-old woman. Thyroidectomy was necessary, respectively, after nine-month treatment with 50 mg daily, two-month treatment with 75 mg daily, and one-month treatment with 50 mg daily. The two women were typical cases of PHT. Conversely, in the first patient, thyroid histology showed features of granulomatous thyroiditis, typical of SAT, without fibrosis or lymphocytic infiltration, typical of HT/PHT, coupled to undetectable serum anti-thyroid antibodies. Our data (1) suggest that not only PHT but also SAT may show resistance to steroid treatment and (2) confirm a previous observation in a single PHT patient that increasing prednisone doses above conventional maximal dosages may not be useful in these patients.