Should neck pain in a patient with Hashimoto's thyroiditis be underestimated? A case and review of the literature

Hashimoto's Thyroiditis (HT) is an autoimmune disease and the most frequent cause of hypothyroidism. Subacute thyroiditis (SAT) overlapping HT is a rare entity. A 69-year-old female patient with HT and multinodular goiter has been followed on levothyroxine replacement therapy for 7 years. She presented with neck pain radiating to the right ear persisting for 2 months. She was prescribed analgesics and antibiotics by other physicians during that period, which did not work. Her vital signs were stable with no tachycardia or fever. The right lobe of the thyroid gland was tender on palpation. Her TSH level was 3.94 mIU/ml, ESR 23 mm/h, CRP 3.2 mg/l, WBC 4900/μl at presentation. Thyroid ultrasonography revealed a hypoechoic area over the tender lobe. Power Doppler imaging revealed almost no blood flow in that area. She was started on methylprednisolone 32 mg/day. At day 10 of therapy, her symptoms had completely resolved. Ultrasonography repeated showed that the hypoechoic area had disappeared. Glucocorticoid dosage was tapered and stopped. Emergence of subacute thyroiditis in a case with preexisting Hashimoto's thyroiditis is a quite rare condition, but should be kept in mind along with a painful attack of HT in the differential diagnosis.