Iodine induced thyroid toxicosis. - 7th_dance

[ArchivalUser]

"Iodine induced thyroid toxicosis" Increased or decreased Radio Iodine Uptake? Confused here.

[ArchivalUser]

Iodine induced thyroid toxicosis happens in patients who are iodine depleted or have any sort or thyroid problem such as an adenoma whereby a small increase in iodide uptake leads to thyroid storm i.e massive release of thyroid hormone....this is called the Jod-Basedow phenomenon.

So if the patient is iodine deficient in first place there wud definitely be increased iodide uptake whether he is given iodide or radio iodine.

[ArchivalUser]

Hey, its nice to hear from you again.
Actually, thats how I made the correlation, but while browsing for the topic..I came across this from another forum.


Examples of hyperthyroidism with increased uptake:
Typically Grave's disease as the autoantibodies stimulate TSH receptor sensitivity enhancing the uptake.
Secondary and tertiary hyperthyoroidism where the elevated TSH levels also stimulate the uptake.
Toxic adenoma in which the overactive adenoma need to take Iodine to support the production of T4.
Example of hyperthyroidism with decreased uptake:
Factitious hyperthyroidism in which the exogenous T4 causes feedback inhibition on the TSH secretion.
Any other exogenous thyroxine sources such as struma ovarii.
Iodine induced thyroid toxicosis.
Release of thyroid hormone by destructive process e.g. temporary hyperthyroidism seen in subacute thyroiditis.
Toxic Nodular Adenoma, the nodule is active (causing hyperthyroidism) but the rest of the gland is with decreased uptake due to suppressed TSH.
Example of hypothyroidism with increased uptake:
Thyroid hormone receptor insensitivity in which the T4 has no peripheral effects (hence the hypothyroidism) and no feedback effects (hence the elevated TSH and increased uptake).
Example of hypothyroidism with decreased uptake:
Hashimoto, De Quervain, and Reidle thyroditis are all associated with decreased Iodine uptake.

[ArchivalUser]

Everything was fine till, he mentioned Iodine induced thyroid toxicosis under Example of hyperthyroidism with decreased uptake.

How is that true?

[ArchivalUser]

It depends on the cause of the thyroid toxicosis as i mentioned for example if a person serum is low on iodine then he is going to have increased uptake but in case he is taking amiodarone for example or has a hypofunctioning adenoma in the thyroid then the uptake is going to be less obviously.

The bottom line about thyroid toxicosis is that the patient has a "PROBLEM" with his thyroid and even a little amount of iodide ions entering the thyroid can lead to a thyroid storm. This wont happen to a person with normal thyroid gland.

My reference is wikipedia https://en.wikipedia.org/wiki/Jod-Basedow_phenomenon

I think if u need more info u need to ask the author of the above article or u can ask "cardio69" or "sarim" these users can help u

[ArchivalUser]

So, increased or decreased uptake depends on what state the thyroid is in. Low iodine thyroid(thirsty thyroid) takes it avidly and causes tyroxicosis (aka Jod Basedow). Endogenously supplied thyroid may be in form of a drug or factitious thyroid intake causes decreased uptake.
Did I get it right?

[ArchivalUser]

Yes like in normal individual if u give them massive amt of iodine it will just inhibit the Na+/I- cotransporter so no uptake.

In people who are low in iodine or have a toxic goiter will have avid uptake

And those who have a hypofuctioning adenoma for e.g will have a low uptake

But most importantly is to note that thyrotoxicosis doesn't depend on amt of iodide ions getting in the thyroid but it happens only in individual who have a "problem" with thyroid so even a small uptake can cause it.

U have to differentiate uptake and thyrotoxicosis do not mix them up.

And when u are talking about factitious intake u are referring to exogenous thyroxine not iodide