What causes low TSH?

My Endocrinologist wants me to have my thyroid surgically removed.  She says I am hyperthyroid.  My T3 and T4 tests have been consistently normal, but the TSH is low.  It is currently 0.035.  I have no symptoms of hyperthyroidism and I am reluctant to part with my thyroid under these conditions.  Any suggestions?  Why are my T3 and T4 levels normal if my TSH is low? Shouldn't my pituitary be pushing the T3 and T4 up?

[FTB4]

Yes your pituitary sends a signal to your thyroid (this is the TSH) then your thyroid responds by secreting hormones into you system, I just had that conversation with my Endo today, in Jan 09 I was diagnosed with Hashimoto's, I asked him if my thyroid had become any smaller since Jan., he said it had not (It is 2.5 times larger than it should be) so I asked if it did not shrink back, would I have to have it removed, he stated that, no, he would not recommend removing it  unless it was dire or causing a severe restriction of the throat and airway or cancerous, He also said it could take a long time to reduce due to the fact that Hashi's keeps the thyroid in an inflamed state since the antibodies (Tcells) do not recognize it and try to eliminate it. I guess every MD has an opinion, but if I was in that situation (After dealing with a few md's) I would seek other opinions prior to having it removed. FTB4

[fluter777]

Thank you.  I think you are right....I need some other opinions....

[goolarra]

Do you know your actual FT3 and FT4 numbers and their reference ranges?  Some people are very comfortable with a TSH similar to yours.

I'd be reluctant to part with it, too.  Definitely get a second opinion (and maybe a third)...

There are drug therapies for hyperthyroidism, also.

Once your thyroid is removed, you'd be HYPO for the rest of your life.

[Smilerdeb]

That last comment is basically 'incorrect'.


*Once your thyroid is removed, you'd be HYPO for the rest of your life.*
Hypothyroidism is a condition that can be fixed by medications.
You dont STAY Hypo lol.

And contrary to what a lot of people here believe....Hypothyroid IS easier to deal with if you have suffered with Graves and Hyperthyroidism.
Believe me, I was close to death 3 times in two weeks due to Thyroid Storm and would never want to go through that again or wish it on my worst enemy.

Hyperthyroidism is like having 240 volts of electricity through your body 24/7....not a nice feeling.

[Smilerdeb]

Sorry Fluter but if I was you....with normal FT3 and FT4 sysmtoms, I would sit tight and wait.....
I wouldnt be having a Thyroidectomy just because my TSH was low.
It could be antibodies causing it or Thyroiditis.
It could even be a viral infection.
There are a lot of causes for low TSH.
Go by your gut instincts and if no hyper symptoms then sit tight.

[goolarra]

Hypothyroidism is kind of like being a fireman....long periods of total and complete boredom, followed by moments of utter and complete terror!  Neither hypo nor hyper is nice. My levo gives me moments of hyper...grrrrrr.

[choirgirl]

My opinion would be to keep your thyroid as long as you can as long as it is functioning and not cancerous.  I had hashimotos for 15+ years and used synthroid to allow it to "rest" and not work so hard.  I had a TT Dec 2007 and the up and down roller coaster of meds has been a mess.  My TT was for a nodule that turned out to be cancerous, so I was glad to have it removed!  If not for the cancer, I wouldn't have done it.  I felt better in the 15 years with hashimotos than in the 1 1/2 years without a thyroid.

[fluter777]

Thanks for your feedback.

My condition is complicated by "hot" nodule that is supposedly the source of the hyperthyroidism.   I can't quite understand why just that nodule can't be removed.

In searching the net, I found a name for a condition with normal FT3 and FT4 and low TSH:   "subclinical hyperthyroidism"  It apparently is not that uncommon.

My TSH:  (dates above, readings second line)
11/3/2004 11/9/2005 4/18/2007 10/12/2007 2/4/2008 4/29/2008 11/17/2008 2/23/2009 4/9/2009
0.714   0.754   0.265   0.306   0.037   0.235   0.075   0.066   0.035

I might have had some mild heart reactions:   AF for 36 hours after eating some EXTREMELY spicey Indian food last month and a heavy heart beat sometimes when I lie down at night.  But it isn't clear.  Anxiety is involved at this point too, which can also produce symptoms.

I really don't want to deal with thyroid meds for the rest of my life.  I have an appt with Dr. Peter Angelos at the U of Chicago in May for a consultation.   He is not in my HMO system, but I've heard very good things about him.   And I'm looking for a more knowledgeable Endocrinologist.