What causes a change in thyroid hormone levels?

In winter of 2000 I was diagnosed with Graves disease.  I was suffering classic symptoms -- very warm, elevated blood pressure, rapid pulse, etc.  Eventually I was administered radioactive iodine to kill the thyroid and began taking medication.  After several months of varying doses and bloodwork, a dose of 137 mcg. became my daily dose.  For the past three years I've gone for an annual check-up with bloodwork to check the thyroid hormone levels.  My most recent check-up was two weeks ago.  Bloodwork shows that my medication dose is too high.  The dr. has reduced the dose to 125 mcg. and asked me to return in two months for lab work.  
My question is:  if my thyroid is dead, what would cause the hormone level to fluctuate (other than medication).  My mother-in-law is convinced it's the soy I consume (I'm a vegetarian), but everything I've read indicats that soy would cause the opposite problem.  Besides, I've been consuming soy products for years.  
I recently started taking Panax ginseng.  That is the only change in diet/supplementation.
I am physically active and lean and remember how much I hated being hypo before my meds were straightened out.  I DON'T want to go there again.  I have no symptoms of hyper.  I remember those, too.  
What's going on?

[Lindagvw]

Thank you for your reply.  Guess I need to educate myself a little more on the pituitary's function.  I'll admit that once everything seemed to be under control, I didn't give much thought to the whys -- I just took the meds.  Thanks again.

[GravesLady]

Dr just lowered my dose to 88 mcg and it has been nine years after RAI for me.

There are various causes for thyroid levels to change or fluctuate:

Thyroid hormones can very throughout the day - example if TSH is 1.5  it can fluctuate 1.0 - 4.0. Are you having your thyroid tested at approx the same trime of day.  Best for hypers in the AM because that is when the thyroid hormones are the highest and hypos in the PM because that is when thyroid hormones are the lowest.

Changes in potency from batch to batch of your thyroid pills. Synthroid brand has been notorious for this, other brands have tended to have more stringent quality controls in place.

Possibly your blood samples have been tested at different labs, or some other lab mix up

Have you changed the timing of when you take your thyroid pill? This can affect the way it's absorbed, whether with or without food. Thyroid is best taken first thing in the morning, on an empty stomach.

Starting/Stopping a High-Fiber Diet. Or if you're taking fiber supplements such as psyllium. These need to be taken at least 2 hrs away from the thyroid pill, as fiber can inhibit absorption of the drug.


Calcium and/or iron supplements .. these also can inhibit absorption of thyroid medication if taken at the same time of day.

Eating/drinking certain foods while taking medicine can change a drug's effectiveness, causing you to get more or less of the drug than prescribed. Some drugs can cause nutrient loss when taken over long periods of time. In some cases, these food-drug interactions can be harmful or even deadly.

Grapefruit or juice/vitamin C, calcium foods/drinks or calcium fortified products, and supplements, should never be eaten or consummed within 3 hours of taking  thyroid medication. It can magnify the dose many times over.
Grapefruit and grapefruit juice do interact with other medications. The scientists believe the contents of the juice or fruit inhibit enzymes in the small intestine that help to break down so many of the drugs we take. If those enzymes aren't available to break down the drug and render it inactive, that means more of the drug makes its way in to the bloodstream. Concentrations in the body are therefore higher.
"Doctors prescribe medications assuming this specific metabolic process is going to take place "Taking grapefruit juice, for example, can circumvent this situation so that you get more drug absorbed than you usually would. So 10 mg of a medication could act more like 20 to 40 mg of the drug."

Many other foods fall into this class of causing interactions with medication.


Are you eating a lot of soy foods, protein powders or low-carb bars, baking mixes etc with soy in them? Soy has been shown to worsen hypothyroid in some people .. you should avoid or sharply limit your intake of soy foods.

Other foods besides soy may possibly affect the thyroid. Vegetables from the brassica family such as broccoli, cabbage, kale, brussels sprouts .. and others. The "goitrogenic property" is destroyed by cooking, so avoid or limit consumption of these foods in their raw state.

Iodine and Kelp Supplements and/or foods containing these - thyroids are extremely sensitive to iodine, and you need to be careful about adding too much iodine to the diet as it can irritate or aggravate the thyroid.  
Some doctors advise against taking iodine or kelp supplements/foods for people with autoimmune problems.


Change of Seasons. Many thyroid patients aren't aware that TSH can change along with the seasons. The research shows that TSH can naturally rise during colder months, and drop to low normal or even hyperthyroid levels in the warmest months. Some doctors will adjust for this by prescribing slightly increased dosages during colder months, and reducing dosage during warm periods. Most, however, are not aware of this seasonal fluctuation, leaving patients increasingly hypothyroid during cold months, or going through warmer months more hyperthyroid. This seasonal fluctuation can be more pronounced in older people, and in particularly cold climates.

Other prescription medications you may be taking .. hormones such as estrogen or birth control pills, antidepressants, cholesterol-lowering drugs, some herbal supplements.


Antacids -- like Tums, or Mylanta, in liquid or tablet forms -- may delay or reduce the absorption of thyroid drugs, and therefore, should also be taken at least two hours apart from when you take your thyroid hormone.

Over the Counter Drugs Like Cough Medicines, Cold Medicines, Decongestants - Most packages of over-the-counter cough and cold medicines and decongestants say "Do not take if you have one of the following..." and then goes on to list thyroid disease. While you should always check with your doctor, it's generally understood that this warning is more applicable for people with hyperthyroidism (overactive thyroid) than hypothyroidism (underactive thyroid). Because these drugs contain stimulants, the logic is for someone with hyperthyroidism to avoid adding even further stimulation or strain on the heart from these drugs. That said, some people with hypothyroidism do find that they become sensitive to ingredients like pseudoephedrine, what you'd typically find in Sudafed or other decongestants. Some doctors will recomend you try only a partial dose, and see if you have a reaction, and only then try to work you way up to the normal dose and see if it bothers you.

Iron, whether alone, or as part of a multivitamin or prenatal vitamin supplement, interferes with thyroid hormone absorption. You should not take your vitamins with iron at the same time as your thyroid hormone, and should allow at least two hours between taking them.


Menopause, with its fluctuating hormone levels, can also impact your TSH levels

Pregnancy

Stress and Illness can affect thyroid levels .. including chronic lack of sleep.

Herbs/Supplements.  Some herbal supplements can have an impact on thyroid function. Herbs such as the ayurvedic herb "guggul," and supplements such as tyrosine, and products containing iodine such as vitamins, or kelp and bladderwrack supplements have the potential to either increase or decrease thyroid function, and thus, TSH can fluctuate.

Progression of Your Thyroid Disease. You may have been diagnosed with autoimmune Hashimoto's Disease a year ago, prescribed thyroid hormone, gone back six weeks later, and your TSH was 2.5. The doctor decided that your levels were fine, and told you to come back in a year. And now, this year's test shows your TSH at 5.7. This sort of increase may reflect the progression of the autoimmune process...in that as antibodies further attack the thyroid, it becomes less and less able to produce thyroid hormone on its own, therefore, TSH will rise. This same process works in the reverse with Graves' Disease, where the same dose of antithyroid drugs that kept you in the normal range six months ago is now leaving you still hyperthyroid, as the thyroid becomes even more overactive.

In addition, in the period post-pregnancy, you may have been diagnosed with a post-partum thyroid problem. For the majority of women, this condition will resolve itself, meaning that over time, you can expect the thyroid to attempt to return to normal, TSH levels will reflect these changes, and your drug dosages will need to be changed in response.

Age.

I wouldn't worry about it too much.  Just make sure you get Labs done regulary so as to stay on top of the situation.
Hope some of these helped, however, not everything is a 100%, that is, so cut and dry (in thyroid).

Good Luck - Good Health!!


                          

                        

[GravesLady]

More thoughts.

Possibility you weren't given a high enough dose of 1 131 to render you totally hypo. therefore leaving you with some thyroid (function) for antibodies to attack and making you a little hyper.
In some cases it might take years for the thyroid to die off completely.  It is  assumed that the ablative dose of RAI destroys all or most of the thyroid tissue, however it may not. It may destroy just enough to assure that you are no longer hyperthyroid, but there can still be significant thyroid tissue left. The remaining tissue can be stimulated to produce more excess hormone by increases in antibody action, and can also eventually be destroyed by antibody action. The normal progression of the disease is for the antibodies to wear the thyroid cells out over time.


If you are taking 125 mcg you probably still have a functioning thyroid and antibodies are probably still attacking it, making your levels change. Until a persons med doses is  approx
.300 mg  when the thyroid is considered completely burnt out, it is considered that there is still a functioning thyroid.
Med dose of:
.75   mg = 3/4 thyroid function
.150 mg = 1/2 thyroid function
.225 mg = 1/4 thyroid function
.300 mg =  total nonfunctioning thyroid

I had RAI going on 10 years,  my doctor just adjusted my does from 100 mcg to 88 mcg after three years, due to a TSH of 0.04.
My levels have been alternating in and out of Lab reference
range. In one time - out the next, in next time - out the next,
with Labs three months apart for 3 1/3 yrs. So before thinking another RAI I will exhaust all med. doses down to zero and then some.

Sometimes I think the thyroid situation or thyroid medical's are not 100%.

[Lindagvw]

Thank you for the wealth of information.  The more I read the more obvious it seems that the best answer to why the hormone level changed is "who knows?"!  I've been going to the same lab, always taking my meds first thing in the morning, eating the same diet -- in short, nothing in my routine has changed except the hormone level.  
Thanks again and good luck and good health to you!

[Lindagvw]

AHA!!  Your most recent post makes the most sense of anything I've read so far.  I just assumed that once RAI was administered, the thyroid was dead.  I've never seen a breakdown showing dose relating to thyroid function.  
I only get lab blood work done every 12 months until now.  With this new dose, he wants me to have it done in two months.  You mentioned getting yours done every three months for all these years.  I wonder if that is a better strategy.  Will ask my dr. about that.
Thanks again for the information.  I feel better about everything now.
Takc care.

[gumper1]

I have been taking synthroid for at least 15 years now,and for some reason i feel my thyroid is not working properly. I have been loosing my hair like crazy,legs are tired dry skin.I have been to  my doctor and she tested me and said my levels are fine. I have been having heart palpataions,i don't know if this is anxiety or what.I do have a appointment at the end of the month with an Endocronolist.Hope she can help.I just wondered if i broke one of my pills in half ant took it along with the other would that cause problems or make me feel better. I am on 0.25. I take kelp on the side trying to help this also with liquid magnesium. If anyone has any answers for me i would appreciate it

[e138]

Yes, soy affects the thyroid. It may actually promote HYPOthyroidism. The three most common isoflavones in it do. But if you say you have Grave's, it should most likely HELP it since Grave's is under the HYPER umbrella, am I right?

[ryfster]

i have been on levothyroxine for over 10 years and my last blood test came back that the thyroid level was somewhat low (hypo) what can cause this?

[jms83]

this goes to anyone having any thyroid issue, each person is different. Just because your levels on paper come back "ok" on paper and in "range" of what doctors say is "normal" is not always correct. If you feel like **** go with your gut. It has taken me over 7 yrs to get a little help and i not only have just a thyroid issue but come to find thyroid cancer. plus im young and noone wants to listen or believe you when your young and look like your probably healthy. I was horribly sick and still feeling horrible at times. I take 100 mcg of synthroid which I think makes me feel worse or depressed and nutty at times as when i was hyperthyroid. i was prescribed Thyrolar and come to find... it may be off the market .. go figure. I do not knw what to do with myself because I am lost. Im 25 and my advice to everyone is everyone is different. It is all personalized per person. Because my 100 doesn't work for me doesn't mean it wont for someone else. And i highly disagree with what someone wrote above about certain dosages for functioning thyroid that is left after surgery and maybe rai. I have no thyroid, I had my rai I don't even have hardly anything left because they left a very small marker. Some people also have to make sure they don't have a parathyroid problem. Ask your doctor to test your parathyroid glands.

[Pickle_slovakia]

Those who have met little success with Synthroid may want to try out a desiccated thyroid med: naturethroid, west throid, armour thyroid.  Some doctors are completely against it, others completely for it.  I know of many who have found more success, and felt substantially better, taking one of these.

[Smilerdeb]

I dont agree with the percentage of the medications to thyroid function.....Graveslady.
Some have no thyroid function whatsoever BUT they are super sensitive to the T4 medication and are only on a low dose.

Everyone is different and believe it or not.....different seasons (weather) can cause fluctuations in thyroid levels.
Stress too.

[Totie]

I had a TT 15yrs ago and take 125mcg.

My levels have changed in the years for 10yrs I was on 200mcg, but TSH levels started going low. (Currently my TSH is .67)

I asked why my levels changed, my PCP said, age, hormones, and life can alter your levels, but I still don't understand how if I am on medication and NOT relying on my thyroid.

[Katfalls]

My doctor said the older you get the less you need. He told me some of his elderly patients only need 25 of hormone. My grandpa lived to 102, had no thyroid and for the last ten years of his life quit taking it altogether. Something to ponder . . .I just went from 100 to 88. Was on 100 for ten years, but just hit age 60!

[Kellian1972]

Does anybody think these labs are treatable for thyroid disease?

TSH 1.94
FT4 7.5
TU 32
FTI 2.4
T3 1.16

I have no idea what to do, endo wants me to take .50mcg of synthroid.  I have had severe symptoms of hyper post partum.

[sweet_hypo]

Your Thyroid seems fine provided these numbers are without Synthroid or any other thyroid medication. You do not need any medication.  Your FT4 is a little high but it fluctuates more and you may get normal results next time.  Your TSH of 1.94 is excellent.  Maybe I do not have some results that your Endo has.  If that is not the case, you may want to get a second opinion (of course from a different Doctor).

[sabitbaloch]

what is the effect of stress during withdraw a sample of  blood from kids vein??

[Barb135]

There is no endocrinologist that monitors this forum.  I don't understand your question, exactly.

Stress, during a blood draw, will not change the test results, if that's what you're asking.