Thyroid inferno refers to the color Doppler appearance of the thyroid gland in active Graves disease (inclusive of variants such as Marine-Lenhart syndrome) and consists of multiple small areas of color flow seen diffusely throughout the gland representing increased vascularity and arteriovenous shunting.
It should be kept in mind that usually in cases of Hashimoto thyroiditis color Doppler study shows normal or decreased flow but occasionally there might be hypervascularity similar to a thyroid inferno . The hypervascularity in Hashimoto disease does not reflect thyrotoxicosis, indeed it appears to be more common in hypothyroid patients .
Thyroid inferno should not be confused with a thyroid storm (a.k.a. hyperthyroid crisis) which refers to an extreme thyrotoxic clinical presentation.