I've just had Reverse T3 tested for the first time. Thought it would be useful to check as my TSH, Free T3 and Free T4 have been low since I started testing in April 2019.
I started on 50mg Levothyroxine for a few months and recently changed to Erfa (30mg) and Levothyroxine (25mg) as per endocrinologist suggestions. I had been taking the new dose for 10 days at the time these blood tests were done. The comments from Medichecks is that all is fine as within the ranges.
I also had some other tests done recently that again showed low cortisol (230 at 9am) also low insulin levels but iron overload . As my short synacthen test showed a normal response (with a slightly low cortisol level at the start), I'm wondering if I can make a case for hypopituitarism as my thyroid and cortisol levels have been low since I started testing 6 months ago, and now I'm showing low insulin. Over the years I've had some blood tests which could be interpreted as borderline diabetic but luckily that was as far as it went.
I'm seeing the endocrinologist again a few weeks and hoping to continue taking NDT, maybe at a higher dose. I'm just wondering whether this Reverse T3 helps my case or not? Any thoughts would be greatly appreciated. I've done some Google research but there's not much info about low reverse T3, I guess because it's not a problem? Thanks for your help!
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ShonaGreen
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It's neither good nor bad, really. rT3 isn't any sort of a problem in and of itself, whether it's high or low. It's like CRP, it can show you if there's a problem but not what it is. And rT3 isn't always to do with your thyroid - and nothing to do with the pituitary.
I'm wondering if I can make a case for hypopituitarism as my thyroid and cortisol levels have been low since I started testing 6 months ago
What, exactly do you call your 'thyroid', what was low? The TSH? With hypopituitarism, the Frees are low, but so is the TSH. And if that was the case, how did you get diagnosed?
Why did you test only ten days after a change in dose? It takes at least six weeks for changes to take their full effect, so those results aren't showing much that relates to the changes.
Hi greygoose , my first thyroid tests in April showed TSH 1.92 (0.35 - 4.50), Free T4 11.8 (11 - 26) and Free T3 2.8 (3.9 - 6.8). After starting on Levothyroxine, and more recently Erfa, my levels have improved but I'd like to get towards the optimal range.
I did the Reverse T3 test to check if I had high levels as I'm still trying to get to the bottom of whether I have a problem with my thyroid, pituitary or neither. I fear that at my next visit to the endocrinologist I may be told that there's no obvious problem so maybe worth stopping all medication, which is what my first endocrinologist and GP think should happen. I really don't want this to happen, as although I'm responding well to the medication, I still have low energy levels, fatigue and just nowhere like what I used to be! This test showed my Free T3 to be the highest it's been since testing, although I know it may not be a true reflection since taking NDT will affect both Free T4 and Free T3.
Now, those labs do show a possible pituitary problem. Or a hypothalamus problem. The TSH should be much higher with such low Frees.
But, by taking NDT, you're masking the problem. It could easily be said that it's the NDT causing the low TSH. Did no-one mention Central Hypo when you had your first test? That was the time to pick it up. A second test a few weeks later, to make sure, then further investigation of the pituitary/hypothalamus. Seems to me that, now, you'd have to come off the NDT, anyway, to prove your point. Unless you can find an exceptionally intelligent and knowledgeable endo. And, I don't know where you'd find one of those. But, you just cannot prove Central hypo when you're on thyroid hormone replacement, unless you can get someone to test the other pituitary hormones.
I've asked my GP and first endocrinologist about the possibility of central hypothyroidism or hypopituitarism but they thought it was unlikely as my levels would be a lot lower.
I'm seeing a new endocrinologist now, he thinks that there's a chance it could be central hypothyroidism but it doesn't matter as would be treated in the same way with thyroid medication. Due to low cortisol from saliva and blood tests, he agreed to the short synacthen test (I responded normally) but suggested I start on Erfa in the meantime.
To be honest I hadn't realised the impact Erfa would have on further testing, but at this point I think I'm at the end of the road now and should just see how things go with Erfa. I'm in contact with the Pituitary Foundation, they agreed that my test results are borderline for a few things, but should have a new MRI of pituitary and thyroid glands. I had an MRI of my head last year which was clear and thought this would have picked up anything strange, but it's possible that didn't look in these areas, or too small to see anything. I'm seeing the endocrinologist in a few weeks so we'll see what happens!
All blood tests for thyroid hormones were introduced for levothyroxine alone.
Levothyroxine is T4 alone (inactive hormone) and has to convert to T3. It does this by converting to RT3 and then into T3. If we take T3 (active hormoned) or any other thyroid hormones (NDT for instance) the blood test cannot correlate. This is an excerpt from a Scientist who was an adviser to TUK before his accidental death. I don't have a link:
This is from Dr. Lowe who would never prescribe levothyroxine, only NDT or T3 for thyroid hormone resistant patients.:
"Dr. Lowe: Some readers will not be familiar with reverse-T3, and I know from experience that many others harbor misconceptions about the molecule. Because of this, I have summarized in the box below what we know about reverse-T3. I've answered your question below the summary.
Conversion of T4 to T3 and Reverse-T3: A Summary
The thyroid gland secretes mostly T4 and very little T3. Most of the T3 that drives cell metabolism is produced by action of the enzyme named 5'-deiodinase, which converts T4 to T3. (We pronounce the "5'-" as "five-prime.")
Without this conversion of T4 to T3, cells have too little T3 to maintain normal metabolism; metabolism then slows down. T3, therefore, is the metabolically active thyroid hormone. For the most part, T4 is metabolically inactive. T4 "drives" metabolism only after the deiodinase enzyme converts it to T3.
Another enzyme called 5-deiodinase continually converts some T4 to reverse-T3. Reverse-T3 does not stimulate metabolism. It is produced as a way to help clear some T4 from the body.
Under normal conditions, cells continually convert about 40% of T4 to T3. They convert about 60% of T4 to reverse-T3. Hour-by-hour, conversion of T4 continues with slight shifts in the percentage of T4 converted to T3 and reverse-T3. Under normal conditions, the body eliminates reverse-T3 rapidly. Other enzymes quickly convert reverse-T3 to T2 and T2 to T1, and the body eliminates these molecules within roughly 24-hours. (The process of deiodination in the body is a bit more complicated than I can explain in this short summary.) The point is that the process of deiodination is dynamic and constantly changing, depending on the body's needs."
p.s. Dr Lowe only took one blood test for the initial diagnosis and prescribed only NDT or T3 (for thyroid hormone resistant patients) and thereafter all concentration was upon small increases until patient was symptom-free.
Well, they were wrong. Your TSH was low but could have been a bit higher and still be CH. The point is that it doesn't correspond to the levels of the Frees. They seem to be incapable of looking at the three levels together and seeing how they react with each other. But, as they have been taught that CH is very, very rare, they rarely entertain the idea and do the necessary testing. I could tell them, from what I've seen on here, it's not as rare as they think it is.
I'm seeing a new endocrinologist now, he thinks that there's a chance it could be central hypothyroidism but it doesn't matter as would be treated in the same way with thyroid medication.
Another clueless one that has totally missed the point. Sure the treatment for the resulting hypo would be the same as for any other cause of hypo. But, the thing is, the pituitary doesn't just make TSH, it makes a lot of other hormones like ACTH and HGH, and they too could be low and causing symptoms. He should test them. There's no cure for CH that I know of, but if you don't replace the other low hormones, just treating the hypo won't be enough to make you well. It could be the reason for your low cortisol. Has he not thought of that?
An MRI won't necessarily pick up the problem with the pituitary - depends what the problem is.
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