|Subtype||Etiology||Neck pain||RAIU||TSH||T4||Thyroid autoantibodies|
|Chronic lymphocytic (Hashimoto's disease)||Autoimmune||No||Variable||Variable||Variable||Present|
|Microbial inflammatory||Bacterial, fungal, parasitic||Yes||Variable||Normal||Normal||Absent|
RAIU = radioactive iodine uptake; TSH = thyroid-stimulating hormone; T4 = thyroxine.
Thyroiditis is a group of inflammatory thyroid disorders. Patients with chronic lymphocytic thyroiditis (also referred to as Hashimoto's thyroiditis) present with hypothyroidism, goiter, or both. Measurement of serum thyroid autoantibodies and thyroglobulin confirms the diagnosis. Subacute granulomatous thyroiditis (sometimes referred to as de Quervain's disease) is a self-limited but painful disorder of the thyroid. Physical examination, elevated erythrocyte sedimentation rate, elevated thyroglobulin level and depressed radioactive iodine uptake (RAIU) confirm the diagnosis. Subacute lymphocytic thyroiditis (silent thyroiditis) is considered autoimmune in origin and commonly occurs in the postpartum period. Symptoms of hyperthyroidism and depressed RAIU predominate. Acute (suppurative) thyroiditis is a rare, infectious thyroid disorder caused by bacteria and other microbes. The rare, invasive fibrous thyroiditis (Riedel's thyroiditis) presents with a slowly enlarging anterior neck mass that is sometimes confused with a malignancy.