Amiodarone-Induced Thyrotoxic Thyroiditis: A Diagnostic and Therapeutic Challenge

Table 2

Clinical and pathologic features distinguishing type 1 and type 2 amiodarone-induced hyperthyroidism^†.

	Type 1	Type 2
Underlying thyroid disease	Yes	No
Thyroid ultrasound	Diffuse or nodular goiter	Normal (hypoechoic) gland (small goiter)
CFDS	Increased vascularity	Normal to reduced vascularity
Thyroid RAIU	Low/normal/increased	Low/absent
MIBI	Thyroid retention	Absent uptake
Pathogenesis	Iodine-induced hyperthyroidism	Destructive thyroiditis
Spontaneous remission	No	Possible
Preferred treatment	Thionamides (plus perchlorate)	Glucocorticoids
Posttherapy hypothyroidism	Unlikely	Possible

Modified from Table 1, Bogazzi et al. [12].
^†Mixed forms of AIT have not been fully understood and are believed to be a combination of iodine-induced hyperthyroidism and destructive thyroiditis from the drug itself.
CFDS: color flow Doppler sonography; RAIU: radioiodine uptake; MIBI: 99mTc-sestamibi.