Jod-Basedow Phenomenon (or Syndrome) is an episode of hyperthyroidism that follows an exposure to excess iodine.

Risk factors:

(1) nontoxic diffuse or nodular goiter

(2) latent Graves' disease

(3) long-standing iodine deficiency

(4) thyroiditis (Hashimoto's, autoimmune, other)

(5) chronic kidney disease or end-stage renal disease (impaired excretion of iodine)


Clinical features:

(1) exposure to excess of iodine

(2) quiescent thyroid tissue becomes hyperfunctioning

(3) subsequent hyperthyroidism/thyrotoxicosis


Sources of excess iodine:

(1) iodinated contrast media for an imaging study

(2) oral iodine supplement

(3) exposure to iodinated antiseptic solutions

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