SAT-364 Refractory Painful Hashimoto’s Thyroiditis

Abstract Disclosure: J.L. Azocar Villalobos: None. C. Lane: None. L. Ereifej: None. R.I. Dorin: None. L.E. Aguirre: None. Background Painful recurrent Hashimoto's thyroiditis (pHT) is an uncommon form of chronic lymphocytic thyroiditis, marked by thyroid pain and tenderness. The differential diagnosis for pHT includes infection, subacute granulomatous thyroiditis (SAT) and malignancy. Unlike SAT, pHT usually shows only slight or temporary relief with steroids. Treatment options include l-thyroxine, NSAIDs, or aspirin; however, if symptoms persist, surgical intervention may be necessary.Clinical Case A 23-year-old female G1P0 with PTSD was referred to endocrinology at 14 weeks gestational age for subclinical hypothyroidism and mild neck pain. Initial labs showed elevated TSH at 5.4 uIU/mL (n 0.465-4.680 uIU/mL), TgAb at 3 IU/mL (n ≤ 1 IU/mL), and TPOAb at 1310 IU/mL (n 0-5.61 IU/mL), with normal FT4 at 1.01 ng/dL (n 0.8-2.2 ng/dL). Levothyroxine 50 mcg daily was initiated, and follow-up labs showed improvement. At 1 month postpartum, the patient reported fatigue, worsening anterior neck pain accompanied by pruritus and rash, neck fullness, voice changes, odynophagia, and compression symptoms when lying supine. Physical examination revealed an enlarged, tender thyroid and a sandpaper-like rash over the anterior neck. Labs showed suppressed TSH < 0.015 uIU/mL and FT4 1.74 ng/dL, and Levothyroxine was suspended. TSH rose to 28.4 uIU/mL within two weeks and peaked to 45 uIU/mL by four months postpartum. Levothyroxine was restarted and gradually increased to 112 mcg daily, TSH was normalized. Further evaluation, including serial thyroid ultrasounds and a neck CT, revealed an enlarged thyroid with persistent heterogeneous echogenicity consistent with Hashimoto thyroiditis and no suspicious lymphoid nodes. Labs showed positive TgAb at 6 IU/mL and TPOAb > 2000 IU/mL. Inflammatory markers were not elevated, CRP at 0.8 mg/L (n ≤ 10 mg/L) and ESR at 11 mm/hr (n ≤ 20 mm/hr). Initial treatment with prednisone 40 mg daily for one week provided temporary relief, while NSAIDs were ineffective. A second, longer trial of prednisone at 40 mg daily for one week followed by a three-week taper provided lasting neck pain reduction but failed to resolve symptoms completely.At 18 months after symptom onset, she was referred to an ENT for consideration of thyroidectomy due to recurrent pHT refractory to treatment with NSAIDs and prednisone.Conclusion Recurrent painful Hashimoto's thyroiditis is a rare cause of recurrent thyroiditis and can be difficult to diagnose and treat. In this case, the lack of response to glucocorticoids, along with normal CRP and ESR levels, led to the diagnosis. Surgery may be an option if other treatments do not adequately manage symptoms. Reference: Kon, Y. C., DeGroot, L. J. Painful Hashimoto's thyroiditis as an indication for thyroidectomy: clinical characteristics and outcome in seven patients. J Clin Endocrinol Metab. 2003;88(6):2667-2672. doi:10.1210/jc.2002-021498. Presentation: Saturday, July 12, 2025