pls explain..hypothyroid how can you have..

  1. Hey guys,
    Can you help me out with this. I know you can and thank you in advance for doing so... Today in lecture my prof spoke on hypothyroidism. She said in this condition you have decreased TSH secretion. (so far so good) She then went on to say that you would have increased levels of TSH with decreased T4 and normal T3. She lost me when she said you would first have decreased TSH secretion but I would actually have an increase of TSH on my labs??? WHAT? I don't follow. Can anyone shed some light and make this a little clearer than mud?:uhoh21:
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  2. 23 Comments

  3. by   runningfool
    I have Hashimoto's. From what I know .1 - 3 is the range of "normal" levels of TSH. The lower the number the more TSH you're producing. The higher the number the less TSH you're producing. Is that clear?
    Think of it this way..... When the thyroid stops producing as much TSH as it should you start packing on the pounds. When you produce too much TSH you start losing weight. Low number = low weight = too much TSH. High number = high weight = too little TSH.
  4. by   dianah
    Think about what TSH is: Thyroid Stimulating Hormone. If the thyroid is hypo-, i.e., NOT working as it should, is sluggish, etc, T3 and T4 will be LOW, metabolism is slowed and the TSH will be elevated. Why? It's the body's way of trying to, well, STIMULATE the THYROID.

    Conversely, if one is HYPER-, that means the thyroid is working WAAAAAAAAAYYYYYY harder than it needs to, thus increasing metabolism (you'll lose weight). And, since the thyroid is working SOOOOOOOOO hard, it doesn't need to be stimulated, so the TSH (Thyroid Stimulating Hormone) number is LOW.

    runningfool, my 9yo developed Hashimoto's, was on PTU for about 3 yr. Is euthyroid now. Hope you're doing well.
  5. by   BonnieSc
    (this was in response to runningfool)

    No, not quite. Remember that TSH is thyroid STIMULATING hormone, not thyroid hormone itself. You can have hypothyroidism due to low levels of TSH... you're not producing enough TSH, so your thyroid doesn't "remember" to produce its hormone.

    However, most adults who have hypothyroidism present with a high TSH. Low levels of circulating thyroid hormone start a negative feedback loop... low thyroid hormone causes the body to produce more TSH, in an effort to stimulate the thyroid, but if you have thyroid disease it doesn't work, leading to more TSH, and so on. Therefore, you have high TSH and low T4 (thyroid hormone).

    To sum up, hypothyroidism can be caused by low TSH or high TSH, depending on the underlying cause.

    Hope that helps! I'm hypothyroid myself, so I've done a ton of reading on it. My TSH was 120 when I was diagnosed.
    Last edit by BonnieSc on Nov 14, '05
  6. by   nurse4theplanet
    my eyes just went crossed haha

    i HATED this lecture in school
  7. by   runningfool
    This won't let me edit my reply. I thought of a better analogy for you.

    Think of TSH as gravity. The perfect amount of gravity allows you to stand up straight with your feet on the ground (TSH range of .1 -3). If the gravitational pull (TSH secretion) becomes too great it pulls you down to the point where you can't stand up (below .1). If the gravitational pull (TSH secretion) is too little you float upwards (above 3).

    I'm not sure how good of an anology that is, but it's the best I can do right now. I don't know. I'm at work and pretty tired.
  8. by   Bipley
    Quote from runningfool
    I have Hashimoto's. From what I know .1 - 3 is the range of "normal" levels of TSH. ...
    I have Hashi's too. New stuff from the American Endo Assoc., normal TSH for Hashi's is a bit different from those without Hashi's. Ideal target TSH is 0.5 - 1.0. Anything under 0.5 can lead to all kinds of problem such as bone loss, etc.
  9. by   Spidey's mom
    I hated this lecture in school too . . .

    Different labs use different values which can also make it confusing. Because I'm looking at the lab values y'all are posting (TSH 120?) and I'm seeing something different on my labs.

    My TSH was 3.82 in May of last year and is now 4.44

    Ref.Range/Females is 0.50 to 6.00 uIU/ml

    My F.T4 is 0.84

    Ref. Range/Females is 0.75 - 1.54 ng/dl

    So, the lab guy says I'm high normal . .. my doc says I'm normal. I'm tired, can't lose weight no matter how much I exercise, am losing hair in a short period of time.

    Don't ya just love medicine??


    steph
  10. by   TheCommuter
    I have had autoimmune thyroid disease, more specifically Graves Disease, since 1998, so I think I can hopefully shed some light on the lab values for you. They are not as clear-cut and dry as they seem.

    Normal TSH levels in the euthyroid (normal functioning) person ranges from 0.5 to 4. Typically, hyperthyroid patients have TSH levels that are below 0.05 whereas the hypothyroid patients have TSH readings that are well above 4. However, the TSH is often within normal limits or less than the 0.5 in secondary hypothyroidism initially.

    My thyroid was grossly overactive (hyperthyroid) for nearly seven years until it was destroyed with radioactive iodine in August 2005. I recently became hypothyroid and am now on Synthroid once daily. However, my TSH levels were at less than 0.01 before I started taking the Synthroid. My endocrinologist paid more attention to my low T4 (thyroxine) and T3 (liiothyronine) blood levels and deemed that I was becoming hypothyroid after being treated with the radioactive pill.

    TSH levels can be high, normal, or very low with hypothyroidism. It is best to look at the entire picture, such as the signs & symptoms, and the T4 and T3 serum levels. In classic primary hypothyroidism, though, the TSH tends to be elevated above 4. I hope I was of some assistance. Good luck to you.
  11. by   runningfool
    Quote from dianah

    runningfool, my 9yo developed Hashimoto's, was on PTU for about 3 yr. Is euthyroid now. Hope you're doing well.

    Thank you, Diana! I feel sorry for your child! That must be hard especially at such a young age. I hope he or she is doing well. I'm fine with it right now. I'm feeling a little better and happier this month because I'm finally starting to lose the weight I've gained! YEA!
  12. by   Tiny1Nisolet
    So, my pt could be hypothyroid and I would see increase levels of TSH because the pituitary is telling the thyroid to get a move on and get to work. That makes perfect sense. If my person is hyperthyroid the pit will lower TSH production in order to get my thyroid to slow down on T3 and T4. I am still a little foggy on my neg feedback loop. How do I know if my person is in a neg feedback? (okay I just went back again. makes more sense. whew, I am tired) tee hee Thanks for the help guys. I appreciate it.
    Last edit by Tiny1Nisolet on Nov 14, '05
  13. by   runningfool
    Quote from Bipley
    I have Hashi's too. New stuff from the American Endo Assoc., normal TSH for Hashi's is a bit different from those without Hashi's. Ideal target TSH is 0.5 - 1.0. Anything under 0.5 can lead to all kinds of problem such as bone loss, etc.

    Oh! That's fantastic! Where did you find this information? I just found an article in the British Journal of Medicine from two years ago stating the new official range was .1 - 3 that I wanted to show my doctor because the lab ranges he uses list 4.6 as the high end of normal.
  14. by   TheCommuter
    Quote from runningfool
    Oh! That's fantastic! Where did you find this information? I just found an article in the British Journal of Medicine from two years ago stating the new official range was .1 - 3 that I wanted to show my doctor because the lab ranges he uses list 4.6 as the high end of normal.
    I'd really hate to sound like a sexist, but I must say this.

    Find a female doctor to treat you for thyroid, whether she's a general/family practicioner or an endocrinoligist. My male doctor was 'less in tune' with my hormones and was overprescribing me with Tapazole. I subsequently gained weight at the rate of 15 pounds monthly until I looked like a beached whale. He saw nothing wrong with this and said I needed 'willpower' ans should have no problems losing weight.

    I switched to a female family practice doctor who understood hormonal issues more proficiently. I lost all the weight and my thyroid levels remained WNL for three years in a row.

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