Features of type 1, type 2, and mixed amiodarone-induced thyrotoxicosis

Type 1 AITType 2 AITMixed AIT
Mechanism of diseaseExcess iodineDestructive inflammatory thyroiditisFeatures of both
Underlying thyroid diseasePresentAbsentFeatures of both
GoiterMultinodular or diffuse goiter normally presentInfrequent; may have small, diffuse, firm, or tender goiterFeatures of both
TSH, early disease courseElevatedNormalVariable
TSH, late disease courseElevatedNormalVariable
Thyroid autoantibodiesPresentAbsentFeatures of both
Radioactive iodine studiesNormal or increased uptakeLittle or no updateFeatures of both
99mTc-MIBIIncreased uptakeDecreased uptakeFeatures of both
Color-flow Doppler ultrasonographyHigh vascularityAbsent vascularityFeatures of both
TreatmentThionamidesSteroidsCombination of both
Spontaneous remissionNoPossibleFeatures of both
Late hypothyroidismNoExtremely rareFeatures of both
  • 99mTc-MIBI = technetium Tc 99m methoxyisobutylisonitrile; TSH = thyroid-stimulating hormone