WHAT IS SUBACUTE THYROIDITIS?
Subacute thyroiditis is also known as de Quervain thyroiditis or granulomatous giant cell thyroiditis.1,2 The most common cause of thyroid pain, it is a self-limited inflammatory disorder in which a painful tender goiter is associated with malaise, fever, and transient thyroid dysfunction.2,3 As with other thyroid disorders, SAT occurs most frequently in women ages 40 to 50.2,3 Thought to be of viral origin, it usually occurs after a URI and commonly correlates with the peak incidence of viral infections (spring/fall).2,3
The disruptive process begins with inflammatory destruction of thyroid follicles.2 This causes leakage of stored colloid, which is broken down, releasing unregulated T4 and T3 into the circulation and resulting in a thyrotoxicosis that typically lasts six weeks.1,2,4 Thyroid cells are incapable of producing new thyroid hormone during this time, so as excess circulating hormone is utilized, T4 and T3 levels become normal, then deficient, and the patient transitions through a period of euthyroidism to transient hypothyroidism.1,2,4 As the disruption of thyroid parenchyma abates, recovery ensues. The follicles regenerate, colloid is repleted, and normal thyroid function is restored.1-4
SAT typically lasts four to six months, although painful thyromegaly may persist for one year after resolution of thyroid dysfunction.2 Throughout the course of SAT, thyroid test results can be confusing, and misdiagnosis of hyperthyroidism or hypothyroidism may occur unless each phase of SAT is recognized.
Phases of SAT >>