[adenure]

#1177127

Naisly,

Where did you hear that the uptake isn’t accurate for Graves diagnosis? I had the possibility of hyperthyroidism caused by postpartum thyroiditis or Graves. I had antibodies, but that can be true for either of the 2 causes. The uptake was seen as the 100% guarantee for a diagnosis. The nuclear doctor and technician told me that Graves Disease percentages are above 20% after 6 hours and I forget what the 24 hour uptake is, but it is (obviously) higher. If my hyperthyroidism had been caused by thyroiditis, the percentages would have been between 1% and 4% according to the nuclear doctor. Hence the scan being considered the definitive diagnostic tool.

As far as treatment, in order to do the scan, a person has to be off of methimazole or PTU for 10 days before the scan. So, you wouldn’t be on any ATD’s at that point.

[Kimberly]

#1177128

Certainly with *any* type of test, it’s important to understand the risks and benefits — and to make sure that any questions have been thoroughly answered by your doctor. It’s also important to know if there are less invasive tests that might yield the same information.

But as Alexis noted, the RAIU Uptake & Scan *can* assist in certain cases in diagnosing the root cause of hyperthyroidism.

If it’s determined that the patient is dealing with thyroiditis, the process is generally “watch and wait”, with beta blockers being used for temporary symptom relief.

And while the basic treatment options (surgery, RAI, ATDs) are the same for Graves’ vs. nodules, the preference shifts to surgery or RAI if one is dealing with one or more overactive nodules vs. Graves’ disease. And in terms of surgery, the type of surgery will be impacted by the definitive diagnosis.

[Naisly]

#1177129

Ok, I left this for a bit, but now that I am feeling better, I’ll add to what I said.

adenure

Quote:

Where did you hear that the uptake isn’t accurate for Graves diagnosis?

From the Mayoclinic They are talking about TSI/TRAb
“Either assay is more accurate (and cheaper) than a radioactive iodine uptake and scan, which are traditionally used to differentiate Graves’ disease from other causes of thyrotoxicosis,” says Dr. Grebe. “TRAB assays and TSI bioassays are also particularly useful in distinguishing hyperemesis gravidarum-related thyrotoxicosis from a first-trimester presentation of Graves’ disease.”

Also, Americans ingest a lot of iodine they get about 450 daily, recommended is 150. This has been known to interfere with the RAIU and WHY it is such a high number now for normal (30% is about normal) — Check out Heart and Stroke Foundation. So this will mess up with the results this is why the false/positive results. It can no longer show clear abnormalities.

The RAIU scan will only show spots with differences in density. That’s is, nothing more, which you can get the same result from a ultrasound.
And the only way to find out if there is cancer is by a FNA
National Research Council of Canada

Btw, it is I-125 they use which is still a radioactive isotope.

Quote:

As far as treatment, in order to do the scan, a person has to be off of methimazole or PTU for 10 days before the scan. So, you wouldn’t be on any ATD’s at that point.

Point I was making was, well just what I said — Most people who are FIRST diagnosed are very very (repeat very) hyper. Their levels are not near in a good place, so again, adding iodine is like adding fuel to the fire.

Hope this cleared some things up.

[adenure]

#1177130

I guess I still don’t get it if antibodies can be present for both postpartum thyroiditis and Graves. How does one know which is the cause if both can manifest antibodies?

As far as diet interfering with the test, I had to do the “LID” (low iodine diet) for 7 days before the uptake scan. Zero iodine- no salt, no seafood, no dairy, no eating out. I pretty much ate steamed veggies, grilled chicken breast, and raw nuts for 7 days and egg whites. Funny thing was once I was done with the 7 days, the taste of salt made me ill! Eating out for the 1st time after the scan- wow, I realized how much salt is in restaurant food!

The I-125 is radioactive, but it doesn’t destroy tissue. I’m sure the nuclear doctor wouldn’t have let me continue breastfeeding after the scan if I-125 was destructive. They were super careful about it; they had the dose specially shipped from their lab in Texas and labeled with the impurity percentage and that it was specifically for the breastfeeding mom.

I mean, it’s all water under the bridge at this point for me, but I don’t see how postpartum thyroiditis and Graves can be differentiated without the scan. Maybe other thyroiditis types can be, but postpartum manifests itself identically to Graves- including the antibodies.

[Naisly]

#1177131

Quote:

but postpartum manifests itself identically to Graves- including the antibodies.

Up to 25% of women have TSH receptor antibodies
As per http://jcem.endojournals.org/content/87/9/4042.long

Quote:

The differential between the two is often straightforward but could be challenging, especially because in some studies up to 25% of women with postpartum thyroiditis are positive for TSH receptor antibody (Table 2⇓). When present, either exophthalmos or a thyroid bruit confirms Graves’ disease.

Thyroid bruit is a ultrasound.

Here is another:
http://www.mayoclinic.com/health/postpartum-thyroiditis/AN00153

Hope this helped answer your question.

[adenure]

#1177132

I have to tell you, if that is the case, then I was misdiagnosed. I don’t have (didn’t have) exophthalmos or a thyroid bruit. Yet, I had antibodies and an above normal percentage on the scan. The nuclear doctors told me that postpartum thyroiditis scans are between 1% and 4% for the uptake (mine was above 30% I think). I had the crappy hand dealt where I couldn’t take the ATD’s to wait it out a year to see if it was postpartum thyroiditis or not (as postpartum usually tapers off at that point and normalizes again). My endo. was 100% certain based on the uptake that I had/have Graves- so I went ahead with surgery. Wouldn’t that suck if he was wrong? Oh well, what can you do? My pathology came back as Hashimoto’s. Kimberly, what’s your take? Again, water under the bridge for me, but perhaps it would help someone else.

[Kimberly]

#1177133

Hello – The medical guidance on distinguishing Graves’ from Postpartum Thyroiditis actually doesn’t provide a clear-cut answer – it pretty much goes through all of the options! This section is on page 1096 of the original journal article, or page 16 if you download as a PDF document.

(Note on links: if you click directly on the following link, you will need to use your browser’s “back” button to return to the boards after viewing, or you will have to log back in to the forum. As an alternative, you can right-click the link and open it in a new tab or new window).

http://thyroidguidelines.net/sites/thyroidguidelines.net/files/file/thy.2011.0087.pdf

“TRAb is positive in Graves’ disease in the vast majority of cases and negative in PPT in the majority of cases (118,119). An elevated T4:T3 ratio suggests the presence of PPT. Physical stigmata of Graves’ disease may be diagnostic (goiter, endocrine ophthalmopathy). The radioiodine uptake is elevated or normal in Graves’ disease and low in PPT.”

Although the guidance notes that antibody testing is useful the “vast majority” of the time – of course, there are always exceptions! And since you were faced with the drastic choices of RAI or surgery if the diagnosis was indeed Graves’, I can totally understand you (and your doctor) wanting that extra level of confirmation!

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