Subacute thyroiditis, also known as de Quervain thyroiditis, is an inflammatory reaction of the thyroid gland, often secondary to a viral infection.

Symptoms are determined by the concurrent hyperthyroid or hypothyroid state. Thyroid function tests during the initial phase reveal suppressed TSH and elevated total T4 and T3 levels.

A radioactive iodine uptake scan reveals a low uptake in the thyroid gland and a preferential uptake in the salivary gland. This is in contrast to the significant uptake by the thyroid gland in Graves’ disease.