[Anonymous]

#1020224

I just got a call from the endos office today saying that I am going underactive and I am to stop taking my medicine for 10 days and then have the uptake scan done. My lab results were TSH .58 T4 .49 and free T3 was 362. I am confused. I see that my T4 is on the hypo side however my TSH is normal and so is my T3. Also what would cause a person to now go the other way I am only taking a small dose of PTU now 100mg a day. Also I am feeling the best I have ever felt. I know I need to talk to the endo but I do not see her until thursday and the nurse was not helpful. I am just confused about what is going on. To me it does not seem hypo?. Can anyone shed any light on this for me? Could I be goin into remission after only 6 months on the PTU? Thanks again all, it is just so nice to talk to someone who understands.

[Anonymous]

#1076401

I’m so glad to hear that you are not hyper now. I hope all goes well tomorrow at the endo. I cannot understand T3, TSH, and T4. It just doesn’t make sense to me. I actually asked the doctor yesterday again and I could tell that I had the “deer in the headlight” look when she was telling me. I figure as long as they know what they are doing I’ll just have to trust them. I felt like I was starting to go hyper again and went to my GP because my heart was palpitating again and my pulse was up some.

I have a good endo. I had my RAI today – the dose seemed high (18.75 mCi) compared to some that I have read in previous postings. She said it was that high because I had a fast uptake scan ????

My prayers will be with you tomorrow.

[Anonymous]

#1076402

Hi standingfirm,

Let’s see if I can help with the definitions of T4, TSH and T3.

T4 is the primary form of thyroid hormone released by our thyroid into our bloodstream. It must be converted into T3 (in the liver and kidneys, primarily, I believe) in order to be used by any body tissue that requires it.

TSH is Thyroid Stimulating Hormone, secreted by the pituitary gland. It is a “messenger” to the thyroid. When it is high, it is yelling at the thyroid to release more hormone. When it is low, it is asking the thyroid to stop releasing so much hormone. Since rapidly fluctuating thyroid hormone levels are a stressor to the body, the TSH typically figures it’s messages based on a type of “running average” of T4 levels. I’m not sure how much time it includes in that “average,” but it’s at least a few weeks’ worth.

T3 is the active form of thyroid hormone, and is very transient. A tiny bit of it is released from the thyroid, but usually it is formed from T4, used and gone within hours.

The most important thing to remember is that TSH takes a long time to register a change in your thyroid hormone levels, as a protection for you. If it registered rapid changes and adjusted often, we might end up feeling rather like a rabid bunny some days, and an arthritic turtle other days. So when your levels are changing quickly (as they are in your particular phase of treatment), it is wise to pay more attention to the T4 than the TSH reading on the blood test. After your treatment is complete and you are managing levels, TSH is the best one to rely on, but for now, it is standard practice to react to the drop in T4 before the TSH shows it.

You may not be going into “remission,” per se, but you do need to manage the PTU dosage very carefully until you reach a maintenance dose. Many people end up changing their ATD dose a number of times in order to maintain “just right” thyroid hormone levels.

I do hope this helps a little. Good luck!

~Ski
NGDF Assistant Online Facilitator

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