The Jod-Basedow effect (also Jod-Basedow syndrome and Jod-Basedow phenomenon) is

hyperthyroidism Hyperthyroidism is the condition that occurs due to excessive production of thyroid hormones by the thyroid gland. Thyrotoxicosis is the condition that occurs due to excessive thyroid hormone of any cause and therefore includes hyperthyroidis ...

following administration of iodine or iodide, either as a dietary supplement,

iodinated contrast Iodinated contrast is a form of intravenous radiocontrast agent containing iodine, which enhances the visibility of vascular structures and organs during radiographic procedures. Some pathologies, such as cancer, have particularly improved visib ...

medical imaging, or as a medication (mainly

Amiodarone Amiodarone is an antiarrhythmic medication used to treat and prevent a number of types of cardiac dysrhythmias. This includes ventricular tachycardia (VT), ventricular fibrillation (VF), and wide complex tachycardia, as well as atrial fibril ...

Pathophysiology

This phenomenon is thus iodine-induced

, typically presenting in a patient with

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

goiter A goitre, or goiter, is a swelling in the neck resulting from an enlarged thyroid gland. A goitre can be associated with a thyroid that is not functioning properly. Worldwide, over 90% of goitre cases are caused by iodine deficiency. The term is ...

(due to

iodine deficiency Iodine deficiency is a lack of the trace element iodine, an essential nutrient in the diet. It may result in metabolic problems such as goiter, sometimes as an endemic goiter as well as congenital iodine deficiency syndrome due to untreated cong ...

), who relocate to an iodine-abundant geographical area. Also, people who have

Graves disease Graves' disease (german: Morbus Basedow), also known as toxic diffuse goiter, is an autoimmune disease that affects the thyroid. It frequently results in and is the most common cause of hyperthyroidism. It also often results in an enlarged thyro ...

toxic multinodular goiter Toxic multinodular goiter (TMNG), also known as multinodular toxic goiter (MNTG), is an active multinodular goiter associated with hyperthyroidism. It is a common cause of hyperthyroidism in which there is excess production of thyroid hormones f ...

, or various types of

thyroid adenoma A thyroid adenoma is a benign tumor of the thyroid gland, that may be inactive or active (functioning autonomously) as a toxic adenoma. Signs and symptoms A thyroid adenoma may be clinically silent ("cold" adenoma), or it may be a functional tumo ...

are also at risk of Jod-Basedow effect when receiving iodine, because the thyroid will then not respond to the negative feedback from increased

thyroid hormone File:Thyroid_system.svg, upright=1.5, The thyroid system of the thyroid hormones T3 and T4 rect 376 268 820 433 Thyroid-stimulating hormone rect 411 200 849 266 Thyrotropin-releasing hormone rect 297 168 502 200 Hypothalamus rect 66 216 386 25 ...

s. The source of iodine may be from the diet, administration of the

for medical imaging, or

amiodarone Amiodarone is an antiarrhythmic medication used to treat and prevent a number of types of cardiac dysrhythmias. This includes ventricular tachycardia (VT), ventricular fibrillation (VF), and wide complex tachycardia, as well as atrial fibril ...

(an

antiarrhythmic Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a group of pharmaceuticals that are used to suppress abnormally fast rhythms (Tachycardia, tachycardias), such as atrial fibrillation, supraventricular tachycardia and vent ...

drug). The hyperthyroidism usually develops over 2 to 12 weeks following iodine administration. In some ways the Jod-Basedow phenomenon is the opposite of two physiological compensation mechanisms (

Plummer effect The Plummer effect is one of several physiological feedforward mechanisms taking place in follicular cells of the healthy thyroid gland and preventing the development of thyrotoxicosis in situations of extremely high supply with iodine. Hist ...

and

Wolff–Chaikoff effect The Wolff–Chaikoff effect is a presumed reduction in thyroid hormone levels caused by ingestion of a large amount of iodine. It was discovered by Drs. Jan Wolff and Israel Lyon Chaikoff at the University of California, Berkeley: in 1948, th ...

, which refers to the short period of thyroid-hormone suppression which happens in normal persons and in persons with thyroid disease, when comparatively large quantities of iodine or iodide are ingested. However, (unlike the Plummer and Wolff-Chaikoff effect), the Jod-Basedow effect does not occur in persons with normal thyroid glands, as thyroid hormone synthesis and release in normal persons is controlled by pituitary TSH secretion (which does not allow hyperthyroidism when extra iodine is ingested).

Precautions in medical imaging

administration for medical imaging, monitoring is indicated in people with

thyroid disease Thyroid disease is a medical condition that affects the function of the thyroid gland. The thyroid gland is located at the front of the neck and produces thyroid hormones that travel through the blood to help regulate many other organs, meaning ...

, such as

Graves' disease Graves' disease (german: Morbus Basedow), also known as toxic diffuse goiter, is an autoimmune disease that affects the thyroid. It frequently results in and is the most common cause of hyperthyroidism. It also often results in an enlarged thyro ...

, or

Hashimoto's thyroiditis Hashimoto's thyroiditis, also known as chronic lymphocytic thyroiditis and Hashimoto's disease, is an autoimmune disease in which the thyroid gland is gradually destroyed. Early on, symptoms may not be noticed. Over time, the thyroid may enlarg ...

. Otherwise, for the general population, routine screening with thyroid function tests is generally not feasible.

History and nomenclature

The Jod-Basedow effect is named for the German word for

iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...

, "Jod" (all nouns are capitalized in German, and German cognates of English nouns with an initial letter "I" preceding a vowel are frequently spelled with initial "J", pronounced as "y" like in "young", thus "Jod" = "y-ode"), plus the name of

Karl Adolph von Basedow Carl Adolph von Basedow (28 March 1799 – 11 April 1854) was a German physician most famous for reporting the symptoms of what could later be dubbed Graves-Basedow disease, now technically known as exophthalmic goiter. Biography Basedow was bo ...

, a German physician who first described the effect. The nomenclature "Jod-Basedow" was carried over intact from the German, rather than being translated, presumably on the erroneous assumption that "Jod" is a surname. Thus, a more informative nomenclature in English, and one that avoids the appearance of an eponym involving a nonexistent "Dr. Jod", would be "the Basedow iodine effect". The Jod-Basedow phenomenon is differentiated from Basedow's disease, which is occasionally used as a synonym for

References

{{Endocrinology Endocrinology