Hypothyroidism

[quickfeet]

I feel so ashamed to ask this question, but at what range of TSH do you typically consider starting T4 replacement? I've read recently that treating patients with TSH <10.0 mIU/L hasn't really shown any benefit in terms of symptoms and shouldn't really be done (except in young women of child-bearing age).

So for example in someone with a TSH of 8.5 and a mildly low T4, do you treat them?

@Raryn

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[Raryn]

I feel so ashamed to ask this question, but at what range of TSH do you typically consider starting T4 replacement? I've read recently that treating patients with TSH <10.0 mIU/L hasn't really shown any benefit in terms of symptoms and shouldn't really be done (except in young women of child-bearing age).

So for example in someone with a TSH of 8.5 and a mildly low T4, do you treat them?

@Raryn

If the FT4 is below the lower limit of normal and the TSH is above the upper limit of normal, I'd treat any value of TSH. The main caveat is that if it is just mildly off and the patient had a recent illness, I might repeat the labs in a couple of months to see if they self-normalize. If the TSH is high and the FT4 is low, this is hypothyroidism.

The bigger question is if the FT4 is in the normal range (though it may be low normal) and the TSH is elevated, who do you treat. In this case, your diagnosis isn't hypothyroidism... it's "subclinical hypothyroidism". Management of this is controversial.

A) Old patients might have a mildly elevated TSH and be perfectly normal. So an elderly person with a TSH up to about 10, I might not treat at all. Even then, it's a question of careful history about whether 10.1 in your 95 year old is really worth treating (but then, there's likely minimal harms to doing so).
B) Younger patients that's less normal. So you might set your limit at about 7 for someone who isn't in their 60s or above.
C) People with positive antibodies or a goiter, you might treat anything above the ULN, just because you're worried about progression. This is a softer call, but certainly one your fair share of experts would support.
D) Women of child-bearing age, especially if they're trying to get pregnant, most especially if they've had a history of miscarriage, you might even treat a TSH >3. (The ULN in your lab might be 3.5, 4, 5, or even 5.5, but you have to understand that the normal range for TSH is heavily dependent on the population it was validated in, and that MOST people fall below 3 on every assay. The big difference is whether that most people is 90%, 92%, 95% or what)
E) People with symptoms (i.e. everyone who is ever tired, constipated, or has dry skin), you can convince to treat anything above the ULN. Or even in the upper half of the normal range. Some of them might even get better due to the placebo effect. This is a super soft call, so I try to avoid it if possible.

 

[quickfeet]

What the heck happened to my original thread? I was trying to re-read @Raryn 's response

 

[cbrons]

Seriously what happened to the original thread?

 

[Smurfette]

What the heck happened to my original thread? I was trying to re-read @Raryn 's response

Hmm...will look into it.

 

[Lawpy]

What the heck happened to my original thread? I was trying to re-read @Raryn 's response

Does the following count? MD & DO - "Normal" serum TSH level

Was going to PM him but I think this is a beneficial for anyone interested.

@Raryn - what is the normal serum TSH for young otherwise healthy people?

Based on reading UpToDate, Harrison's and a few endocrinology texts, I haven't found a definitive answer. However, I did recently read this from the ATA/AACE Guidelines:

https://www.aace.com/files/hypothyroidism_guidelines.pdf



^ So in an otherwise healthy 30 year old female or heck even 20 or 25 year old with a few vague symptoms that may or may not be related to PH, what do you do with a TSH of 4.0 mIU/L?

It's controversial.

The normal range for any lab test is determined as the 95% confidence interval for a sample of "young", "healthy" controls. Traditionally, that range for TSH has been ~0.5-5.0, though I've seen the ULN depending on the lab being anywhere from 4.5 to 6.0. The problem is that that 95% confidence interval is primarily grouped in the lower half of that range and determining "healthy" is difficult. If you rigorously screen your control population and exclude anyone with even a family hx of thyroid disease, you end up with a normal TSH range closer to 0.3-3.0, with that ULN being sometimes even as low as 2 or 2.5.

What to do with these intermediate TSH values (in the 2.5 to 5 or even 2.5 to 10 range) is something that if you ask three endocrinologists you'll get four opinions. Everyone is pretty certain that in pregnant women you should get the TSH < 2.5 in the first trimester and <3 thereafter (though the evidence on that is mixed as well), but for every other population it's really hard to say. Women of childbearing age I'll commonly start on LT4 to get them under 2.5. Anyone with clear symptoms is worth a trial of therapy as well, though clear symptoms is a nebulous thing to define (everyone is fatigued if you ask them often enough).

Other expert advised individuals to treat are those with a TSH above 10, those with a goiter, and those with positive antibodies. If you search for evidence supporting treatment in each of those cases, it's hard to get a clear answer. For a young person with these indications, I tend to err on the side of treatment.

The opposite problems happens with elderly individuals btw. The normal range is based on young people, but TSH tends to go up as you get older. So a TSH of 6 or 7 in an 85 year old might be perfectly normal, and it's even more controversial whether or not to treat them. Without clear symptoms, if a geriatric patient has a TSH <10, I typically avoid treating them.

Can also call on @rokshana for another opinion.

Thanks, this was very helpful.
I also have a few other related questions:

1. Is it standard to send for TPO antibodies in every patient who is technically subclinical hypothyroidism? I see it mentioned that it often helps stratify those who will go on to develop overt hypothyroidism, but I don't see general cutoffs and recommendations on what to do with those numbers.
2. In elderly patients on Synthroid (I'm talking over 75), what is a generally reasonable TSH? E.g. is a TSH below 2 in this population considered overtreatment? I can't get a clear answer on this.

1) Depends on who you ask. The risk of progression to overt hypothyroidism is proportional to antibody titer and TSH but never rises much above 50 or 60% even with a high antibody titer. If you're not sure whether you want to treat, get antibodies. But if they're 60 years old with a TSH of 4.6 (and the ULN at your lab being 4.5), I wouldn't get them.

2. I get them to somewhere in the normal range if I'm treating them, but I do my best to avoid treating them. And I certainly don't try to push them down to 1.0 or anything. Risk for afib and osteoporosis goes up if you do.

And yes, fully agree with @rokshana. I tell all my patients that they have to have realistic expectations. They won't ever feel like they were 22 years old again, and not all fatigue is a thyroid, testosterone, or adrenal issue. Lots of crazy people on the internet that try to convince them otherwise though, including too many doctors that treat patients with t3 until they become thyrotoxic and "feel good".

I probably got confused with something else but still useful stuff. Sorry!

 

[deleted109597]

Out of abundance of caution pertaining to asking medical advice, it was closed. On further investigation, this seemed hasty, so we've reopened it.

 

[Raryn]

Out of abundance of caution pertaining to asking medical advice, it was closed. On further investigation, this seemed hasty, so we've reopened it.

There was another thread that seems to have been deleted. It was a specific question on what threshold for TSH people generally use to treat. I think mine was the only response to it, but that I'm not sure.

 

[deleted109597]

There was another thread that seems to have been deleted. It was a specific question on what threshold for TSH people generally use to treat. I think mine was the only response to it, but that I'm not sure.

That's the one I'm referring to. https://forums.studentdoctor.net/threads/hypothyroidism.1271862/

 

[Raryn]

That's the one I'm referring to. https://forums.studentdoctor.net/threads/hypothyroidism.1271862/

"
The requested thread could not be found."

 

[deleted109597]

"
The requested thread could not be found."

It's fixed and they're merged now.

 

[cbrons]

If the FT4 is below the lower limit of normal and the TSH is above the upper limit of normal, I'd treat any value of TSH. The main caveat is that if it is just mildly off and the patient had a recent illness, I might repeat the labs in a couple of months to see if they self-normalize. If the TSH is high and the FT4 is low, this is hypothyroidism.

The bigger question is if the FT4 is in the normal range (though it may be low normal) and the TSH is elevated, who do you treat. In this case, your diagnosis isn't hypothyroidism... it's "subclinical hypothyroidism". Management of this is controversial.

A) Old patients might have a mildly elevated TSH and be perfectly normal. So an elderly person with a TSH up to about 10, I might not treat at all. Even then, it's a question of careful history about whether 10.1 in your 95 year old is really worth treating (but then, there's likely minimal harms to doing so).
B) Younger patients that's less normal. So you might set your limit at about 7 for someone who isn't in their 60s or above.
C) People with positive antibodies or a goiter, you might treat anything above the ULN, just because you're worried about progression. This is a softer call, but certainly one your fair share of experts would support.
D) Women of child-bearing age, especially if they're trying to get pregnant, most especially if they've had a history of miscarriage, you might even treat a TSH >3. (The ULN in your lab might be 3.5, 4, 5, or even 5.5, but you have to understand that the normal range for TSH is heavily dependent on the population it was validated in, and that MOST people fall below 3 on every assay. The big difference is whether that most people is 90%, 92%, 95% or what)
E) People with symptoms (i.e. everyone who is ever tired, constipated, or has dry skin), you can convince to treat anything above the ULN. Or even in the upper half of the normal range. Some of them might even get better due to the placebo effect. This is a super soft call, so I try to avoid it if possible.

If the FT4 is below the lower limit of normal and the TSH is above the upper limit of normal, I'd treat any value of TSH. The main caveat is that if it is just mildly off and the patient had a recent illness, I might repeat the labs in a couple of months to see if they self-normalize. If the TSH is high and the FT4 is low, this is hypothyroidism.

The bigger question is if the FT4 is in the normal range (though it may be low normal) and the TSH is elevated, who do you treat. In this case, your diagnosis isn't hypothyroidism... it's "subclinical hypothyroidism". Management of this is controversial.

A) Old patients might have a mildly elevated TSH and be perfectly normal. So an elderly person with a TSH up to about 10, I might not treat at all. Even then, it's a question of careful history about whether 10.1 in your 95 year old is really worth treating (but then, there's likely minimal harms to doing so).
B) Younger patients that's less normal. So you might set your limit at about 7 for someone who isn't in their 60s or above.
C) People with positive antibodies or a goiter, you might treat anything above the ULN, just because you're worried about progression. This is a softer call, but certainly one your fair share of experts would support.
D) Women of child-bearing age, especially if they're trying to get pregnant, most especially if they've had a history of miscarriage, you might even treat a TSH >3. (The ULN in your lab might be 3.5, 4, 5, or even 5.5, but you have to understand that the normal range for TSH is heavily dependent on the population it was validated in, and that MOST people fall below 3 on every assay. The big difference is whether that most people is 90%, 92%, 95% or what)
E) People with symptoms (i.e. everyone who is ever tired, constipated, or has dry skin), you can convince to treat anything above the ULN. Or even in the upper half of the normal range. Some of them might even get better due to the placebo effect. This is a super soft call, so I try to avoid it if possible.

I have some F/U questions:

My algorithm, if you will:

If TSH ≥4.5 mIU/L but <10 mIU/L --> Immediately repeat TSH and free T4

• If repeat TSH is >4.5 and free T4 is low, then treat
• If repeat TSH is >4.5 and free T4 is normal or high, then don't treat, and repeat both tests within 3 months along with test for anti-TPO antibodies
• If repeat TSH is normal and free T4 is low, then ??????????????

1. Thing I have trouble with is who definitely does and does NOT need anti-TPO antibodies ordered. The UpToDate article as well as Harrison's are not completely clear on this. Can you provide any guidance?
2. Can you address what you would do in the 3rd scenario above?
3. What am I supposed to do with someone in the 2nd scenario who also has positive anti-TPO antibodies. I guess I never understood what exactly the purpose of having this data was, other than the fact that they need more close monitoring?

 

[Raryn]

I have some F/U questions:

My algorithm, if you will:

If TSH ≥4.5 mIU/L but <10 mIU/L --> Immediately repeat TSH and free T4

• If repeat TSH is >4.5 and free T4 is low, then treat
• If repeat TSH is >4.5 and free T4 is normal or high, then don't treat, and repeat both tests within 3 months along with test for anti-TPO antibodies
• If repeat TSH is normal and free T4 is low, then ??????????????

1. Thing I have trouble with is who definitely does and does NOT need anti-TPO antibodies ordered. The UpToDate article as well as Harrison's are not completely clear on this. Can you provide any guidance?
2. Can you address what you would do in the 3rd scenario above?
3. What am I supposed to do with someone in the 2nd scenario who also has positive anti-TPO antibodies. I guess I never understood what exactly the purpose of having this data was, other than the fact that they need more close monitoring?

The only thing I'd say about an immediate repeat is just be careful if the patient had a significant illness (like, hospitalization requiring, not the sniffles) recently. May be better off waiting a month or two if they have.

1. If you're going to treat regardless, no point in getting antibodies. Young women. People with really high TSH. Big goiters. Whatever. If you're not sure whether to treat (especially if they're pregnant), get the antibodies. Never trend the antibodies, there's no correlation between levels and disease.
2. Ignore it typically. Repeat levels in 6 months or something just so it doesn't seem to the patient that you're blowing it off, but this is almost never real. Unless they have primary pituitary pathology (or are pregnant, which significantly complicates matters), this is far more likely to be an error in measurement than it is to be anything treatable.
3. People with positive antibodies and subclinical hypothyroidism have a much higher chance of progressing to true hypothyroidism. Expert opinion is to just treat them like they have hypothyroidism.

That all said, you have to be careful with some patients. There's a significant cottage industry of "patient advocates" for thyroid disease who write books, have facebook groups, websites, etc advocating "full thyroid panels" every visit (TSH/FT4/FT3/reverse t3/multiple antibodies). Many of them also advocate a number of other tests like "full iron panels", q6h salivary cortisols (to eval for "adrenal fatigue"), various stool studies for nonexistent parasites, various allergy panels, etc. They then advocate special diets to reduce thyroid antibodies, use of dessicated pig thyroid hormone rather than synthetic human, various multi-hundred dollar support supplements, and god knows what else. None of it has any evidence whatsoever for it except anecdote. A normal TSH (and I mean truly normal, say 0.5-3.5) will rule out >99% of thyroid function abnormalities that would be diagnosed by any reasonable physician. If you have a patient who starts asking for this stuff, good luck.

If you ever want to be amazed at the insanity these folks come up with, check out Stop the Thyroid Madness™ - Hypothyroidism and thyroid mistreatment (do NOT follow their management advice).

 

[cbrons]

If you ever want to be amazed at the insanity these folks come up with, check out Stop the Thyroid Madness™ - Hypothyroidism and thyroid mistreatment (do NOT follow their management advice).

Yikes.

Thanks for your answers to my above questions.

 

[cbrons]

While you are answering questions @Raryn , I am curious what your opinion is regarding target TSH in elderly on T4.

For some reason, in my notes, I have a target of 4.5-5.5 mIU/L in "elderly" patients. E.g. A tsh of 1.4 in a person who is 70 years old means they need their Synthroid dose reduced. What is your opinion or feeling on this issue of appropriate therapeutic TSH in patients >65?


Question #2 - Excepting women of child bearing age, is there any other situation/patient where you would treat subclinical hypothyroidism (e.g. completely normal free T4)?

 

[Raryn]

While you are answering questions @Raryn , I am curious what your opinion is regarding target TSH in elderly on T4.

For some reason, in my notes, I have a target of 4.5-5.5 mIU/L in "elderly" patients. E.g. A tsh of 1.4 in a person who is 70 years old means they need their Synthroid dose reduced. What is your opinion or feeling on this issue of appropriate therapeutic TSH in patients >65?

This is expert opinion.

The reasoning is that there's observational data that elderly individuals with lower TSHs, even within the normal range, are at higher risk for osteoporosis and atrial fibrillation. You ask three Endocrinologists what to do with that information and you'll get four opinions though. I'd personally shoot for a target in the upper half of the normal range (say, 3.5-5).

So yes, TSH of 1.4 I'd probably reduce the dose.

Question #2 - Excepting women of child bearing age, is there any other situation/patient where you would treat subclinical hypothyroidism (e.g. completely normal free T4)?

As I posted above, people with subclinical hypothyroidism who could reasonably be treated within the standard of care:

0) Women of childbearing age (especially if they're trying to get pregnant and most especially if they've ever had a miscarriage)
1) People with positive antibodies
2) People with goiters
3) People with a normal FT4 but a TSH >10 (and in younger patients, even >7)
4) People with symptoms (I hate this criterion, because show me a single American who is never tired, constipated, or complaining about how hard it is to lose weight)

@rokshana might be able to give you another viewpoint. I think there's another of us floating around the website too, but heck if I remember who.