Monday, August 08, 2005

Iodine from Large Amounts of Kelp Causes Goiter Progression in a Young Lady

36 year old female is seen in consultation for goiter, referred by her family physician. Prior work up included an FNA that was read as colloid goiter. Ultrasounds have shown progressive enlargement. There is a family hx of goiter in a sibling.
She as a history of ingesting a large amount of iodine containing supplements. She eats seaweed, kelp, and powdered seaweed at each meal. Bilateral nodular goiter is noted on neck examination. TFT's were borderline with TSH of 2.8 N 0.4-2.5,FT4 0.89 N 0.8-2.0 FT3 2.6 N 1.9-5.1 TG 154, TPO <10.1 TG AB <1,0. 24 hour urine free iodine was 3002 mcgs N 100-400.

The excessive use of iodine containing products such as seaweed will cause progressive thyroid enlargement as in this case.It can cause hypothyroidism in patients with autoimmune thyroid disorders, such as Hashimoto's thyroiditis. Non-toxic goiters can become toxic goiters. Even a normal thyroid that has 1/2 left after lobectomy may fail under the pressure of high dose iodine supplements.