AIT

Q: There are how many types of Amiodarone-Induced Thyrotoxicosis (AIT)?

Answer: Two

There are two types of AIT. The distinction plays an important role and helps clinicians determine whether to continue amiodarone or not?

Type I is marked by increased synthesis of thyroid hormones, i.e., T4 and T3. These patients usually have the preexisting disease. The excess iodine results in providing increased substrate leading to thyroid hormone production.

Type II is destructive in nature and causes excess release of T4 and T3. There is no increased hormone synthesis. There is a direct toxic effect on thyroid follicular epithelial cells.

#endocrinology

References:

1. Martino E, Bartalena L, Bogazzi F, Braverman LE. The effects of amiodarone on the thyroid. Endocr Rev 2001; 22:240.

2.Lambert M, Unger J, De Nayer P, et al. Amiodarone-induced thyrotoxicosis suggestive of thyroid damage. J Endocrinol Invest 1990; 13:527.

3. Brennan MD, Erickson DZ, Carney JA, Bahn RS. Nongoitrous (type I) amiodarone-associated thyrotoxicosis: evidence of follicular disruption in vitro and in vivo. Thyroid 1995; 5:177.