Is thyrotoxicosis a common finding of subacute thyroiditis?

Subacute thyroiditis is a self-limited thyroid condition
associated with a triphasic clinical course of hyperthyroidism, hypothyroidism, and
return to normal thyroid function. Subacute thyroiditis may be responsible for 15-20% of
patients presenting with  href="http://emedicine.medscape.com/article/767130-overview">thyrotoxicosis
and 10% of patients presenting with href="http://emedicine.medscape.com/article/122393-overview">hypothyroidism.
Recognizing this condition is important, because it is self-limiting, and no specific
therapy, such as antithyroid or thyroid hormone replacement therapy, is necessary in
most patients.

Thyroiditis refers to inflammation of the
thyroid gland. Subacute thyroiditis (SAT) is a self-limited condition characterized by a
triphasic course of href="http://emedicine.medscape.com/article/121865-overview">hyperthyroidism
followed by  href="http://emedicine.medscape.com/article/122393-overview">hypothyroidism
and ending with euthyroidism. Subacute thyroiditis may account for 15-20% of
thyrotoxicosis presentations and 10% of hypothyroidism presentations. The thyrotoxicosis
results from release of preformed thyroid hormone. This phase lasts 4-10 weeks. The
disease undergoes remission in 2-4 months. At this time, the thyroid is depleted of
colloid and is now incapable of producing thyroid hormone, resulting in hypothyroidism.
The hypothyroidism may be mild and not requiring any therapy. As the follicles
regenerate, the euthyroid state is restored. Up to 95% of patients return to this normal
thyroid state.

Subacute thyroiditis (subacute granulomatous
thyroiditis) is characterized by neck pain or discomfort, a tender diffuse goiter, and a
predictable course of thyroid function evolution. Hyperthyroidism is typically the
presentation followed by euthyroidism, hypothyroidism, and ultimately restoration of
normal thyroid function ( href="http://www.uptodate.com/contents/subacute-thyroiditis#subscribeMessage">figure
1). The diagnosis and management of subacute thyroiditis will be provided
here.