Jod-Basedow phenomenon

Jod-Basedow phenomenon is hyperthyroidism following iodine intake in a person with long term underlying thyroid disease.

Pathology

Jod-Basedow phenomenon occurs due to either overactivation of the entire thyroid gland or, more commonly, autonomous nodules within the gland after iodine repletion without adequate feedback control from the pituitary gland. This escape from the protective Wolff-Chaikoff effect is called the Jod-Basedow phenomenon. Patients at risk are elderly and those from low iodine intake regions.

Etiology

Underlying causes include:

• endemic goiter
• Graves disease
• toxic multinodular goiter
• autonomous thyroid nodules in the elderly
• thyroid adenoma

Exogenous sources of iodine include:

• iodinated contrast
• oral supplement 
• amiodarone

History and etymology

The Jod-Basedow effect is named after "jod", the German word for iodine, and Carl Adolph von Basedow (1799-1854) , the German physician who first described the effect. He also described Basedow disease, better known to the English-speaking world as Graves disease.