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Low TSH and high blood sugar

Hi I have question that I think has baffled my Doctor. 3 months ago I went to doctors office cause I was not feeling good. They did blood work and found my TSH to be 0.039 and my A1c to be 6.0 and blood glucose is 119.
My t3 and t4 are normal. They said your sugar is high and to cut sugars. Which I beleive I did and lost 10 pounds from 150 to 140 and being 5 feet 5.5 inches, and increasing my exercise to 40 minutes/5 days a week.
After reducing my thyroid dose which I am hypothyroid because of iodine 131 given to me for hyperthroidism in 1978
From .125 to .112 my thyroid level is not better.
Latest numbers after 3 months, on dose of synthroid generic...0.100 new dose after several weeks my TSH is 0.020
and my A1c is now 6.4. Why is my TSH going down and not up?
I have symptoms of  itching skin, increase urination, jittery, nervousness, and what I eat I keep losing 2 pounds every 3 weeks of weight.
Thanks...
Best Answer
1756321 tn?1547095325
My insulin resistance worsened and I developed pre diabetes (also called impaired glucose intolerance) due to hyperthyroidism.

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1756321 tn?1547095325
Not sure if medical studies would use the term pre diabetes (not that I've searched extensively lol) but impaired glucose intolerance is another term for pre diabetes as I mentioned.

Hyperthyroidism induces glucose intolerance by lowering both insulin secretion and peripheral insulin sensitivity - J Med Assoc Thai. 2006 Nov;89 Suppl 5:S133-40....

"The prevalence of glucose intolerance in hyperthyroid state was 39.4% [impaired glucose tolerance (IGT) 31.5% and diabetes mellitus (DM) 7.9%]. This was significantly higher than that of 30.7% [IGT 19.2% and DM 11.5%] in healthy volunteers (p < 0.05). Glucose intolerance was associated with higher systolic blood pressure, higher mean arterial pressure, lower CIR, and higher T4 levels but not with the levels of T3. IA and HOMA2-%S significantly improved when achieving a euthyroid state despite the increase in body mass index.

CONCLUSION:
In conclusion, glucose intolerance is common in hyperthyroidism. Both impaired insulin secretion and decreased peripheral insulin sensitivity are the factors contributing to the development of abnormal glucose tolerance in the hyperthyroid state."

Medscape - Excess Thyroid Hormone and Carbohydrate Metabolism - Endocr Pract. 2009;15(3):254-262....

"The hypermetabolic state of hyperthyroidism demands an increase in glucose metabolism for additional energy supply to the muscle. Early cell culture studies that evaluated insulin action on skeletal muscle in hyperthyroidism suggested enhanced or intact action at the level of the insulin receptor.[25,41,42] However, hyperthyroid patients demonstrate marked insulin resistance during a 3-hour oral glucose tolerance test that resolves with treatment of hyperthyroidism.[43] This argues against the initial findings of increased insulin sensitivity,[25,41,42] and again, like in the liver, suggests that the mechanism of insulin resistance in hyperthyroidism is downstream from the insulin receptor.

Underlying glucose intolerance may be exacerbated in hyperthyroidism because overweight individuals display higher levels of insulin resistance by homeostasis modeling assessments of insulin resistance than do thinner counterparts.[20,23] In patients with Graves disease or toxic nodules, the level of elevation of T3 correlates directly to the degree of peripheral insulin resistance by homeostasis modeling assessments of insulin resistance.[44]"
Helpful - 0
649848 tn?1534633700
COMMUNITY LEADER
I've already explained about your TSH.  It's quite common for TSH to be suppressed when one is taking a thyroid hormone replacement.  They had to completely take me off thyroid medication in order to get my TSH to come up, which, of course, sent me back to hypo he!!   By decreasing your thyroid med, they are doing the same thing with you - that's why you feel terrible, can't sleep and have brain fog.

Your itching could be caused from diabetes or it could be caused by a reaction to fillers, binders or dye in your thyroid medication.

Of course, since it appears that you have diabetes, as well as being hypo, you're going to feel worse.  They should be putting you on something that will help get your blood sugar under control.  

Obviously your doctor knows very little about, either, thyroid or diabetes, so, yes, you might want to look into seeing a specialist, as waiting another 3 months will only make things 3 months worse.

You must watch the specialist though.  Some endocrinologists specialize only in diabetes and know very little about thyroid, so make sure you get one well versed in both, since you're dealing with both.

Will look forward to seeing the FT3 and FT4 results.  If they didn't do them, walk, don't run from that doctor...
Helpful - 0
Avatar universal
I will check tomorrow and find out my FT3 and FT4...hopefully they did do them last Friday..I will let you know as soon as I can..
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Avatar universal
Does anyone know why my TSH won't come up? T3 and T4 are supposedly normal.
And do you all think I should see a specialist, cause right  now my regular Doctor and a nurse practitioner is treating me and I really wonder if they aren't helping me at all or just leave things as they are and wait another 3 months..
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Avatar universal
I am glad you told me that because it seems that all this sugar stuff and pre diabetic stuff started when my TSH level was too low.
But they can't seem to increase my TSH level...its been about 3 months now..
Helpful - 0
Avatar universal
That's very interesting but it's my doctor who said that blood sugar was related to low TSH levels. As of now my TSH is .02 but I have itching and it's driving me crazy. My doctor said T3 and T4 are normal. But I feel terrible like sometimes brain fog, cannot sleep except for 3-4 hours a day. I am urinating a lot more which could be my A1c number of 6.4. I am going tomorrow to talk to Nurse practitioner not my doctor cause he's busy. I also had a ultra sound on my bladder cause of increase urination last Friday but Docor has been too busy to give me results..imagine that!
Helpful - 0
649848 tn?1534633700
COMMUNITY LEADER
Do you have documentation showing that hyperthyroidism can cause pre-diabetes?  I've searched everywhere and can't find a link between the 2, since pre-diabetes is not a recognized disease and is a forerunner to type II diabetes which is not autoimmune.
Helpful - 0
649848 tn?1534633700
COMMUNITY LEADER
No, I don't.  TSH is a pituitary hormone and its sole responsibility is to stimulate the thyroid to produce thyroid hormones.  Your thyroid was destroyed via RAI, therefore, TSH should play no role for you.

As I noted before, TSH neither causes nor alleviates symptoms.

I can't say your thyroid is "out of whack" until I know what your FT3 and FT4 levels are.  Simply having a low TSH does not constitute having a thyroid out of whack.  My own TSH has been at < 0.01 to 0.01 for the past 6 years and I'm fine, because my FT3 and FT4 levels are good.  I do have some issues with blood sugar levels, though and have to pay attention to what I eat - that's totally separate from my thyroid issues.
Helpful - 0
Avatar universal
Do you think that my low TSH level is messing with my blood sugar or no? My doctor thinks it is somehow.
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Avatar universal
I will find them out and get back with you when I call my doctor today. I have intense itching as well caused by thyroid out of whack? Or not?
Helpful - 0
649848 tn?1534633700
COMMUNITY LEADER
What are your Free T3 and Free T4 levels?  Please post them, with reference ranges, which vary from lab to lab and have to come from your own report.  TSH does not cause or alleviate symptoms. It's the actual thyroid hormones that cause (or alleviate) symptoms, with Free T3 correlating best.

Your A1c indicates that you have diabetes and that's what's causing your symptoms of frequent urination, weight loss, etc. Are you keeping track of your daily fasting blood sugars?  What about your post prandial blood sugars?  Talk to your doctor about this... it's very important to get that under control.  Sugar is not the only thing you need to cut to get your blood sugar under control.  There are many other simple carbs that spike your blood sugar as well, that you need to stop eating.
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