June 1, 2023

TSH tends to be the mystifying lab. When do you really have to worry? When and how to treat?

Made simple though weekly videos to help save you time frustration and help you yourself a little bit mystified by tsh wondering well you know what is the monitor them like any of that stuff like about is managing high tsh s so before we dive into this case study quick note nurse practitioners so it’s kind of similar to the way that i’m talking practical all of the labs

That you see in primary care so kind of touching on a very compact very just like straight to the point let’s do this kind of way it in collaboration with a couple of specialists just to kind of give that in primary care while at the same time just being really thorough and it’s but if you’re interested in that i’m super super psyched about it have more details of when

It’s gonna be rolled out it’s gonna be in the next further ado i’m going to share my screen study so this is janelle she’s 56 she’s a new patient establishing care and she heavier periods for the last two months and they’ve been more irregular recently specific pounds she used to take levothyroxine in the past she doesn’t past surgical history include hypothyroidism anemia

Close discectomy this visit her blood pressure is 169 over 79 heart rate of 77 oxygen is 98 here because i’m not really getting into like fatigue is a complaint today but history that i said so far and then her physical exam was normal so the plan so of holistic hair at the end so i’m gonna of anemia and she’s feeling fatigued a cmp a hemoglobin a1c a tsh and so i have they

Will automatically order a t4 into t3 free t4 and t3 if it comes back lipids cholesterol according to uspstf screening guidelines so here her lab hemoglobin a1c of 5.7% which her puts her into the pre-diabetes range her thyroid so it means that there is a high tsh signifies that there is a low it’s kind of opposite to what you think and it’s diagnosed by labs also based

On pregnant adults if you’re going into pregnancy pregnant women this is outside endocrine or you need to consult with the endocrine when you see them so what according to the labs and management um not going as in depth with the workup the tsh and what is the total of 3 t4 so you really you need to look at both so and free t4 normal range is 0.6 to 1.8 and the note here

I want to make is that active kind of freeform this is t4 so are unbound rather not the active repeat step you can either add on the free t4 the excuse me yes the free t4 if you repeat it to make sure that it’s not like a transient or abnormality there’s potassium or low platelets in terms of like high risk of artifact but that’s similar to my other presentations i kind of

Gave those danger ranges and it’s mekomo which you probably learned about in school is very uncommon mental status of present to you and you’d kind of notice on them to not your clinic if number of tsh the highest i think i’ve seen is like thirty maybe fifty maybe main scenarios one is a high tsh with a low t4 and that’s considered overt one is considered subclinical but it

Depends on their symptoms so if they subclinical hypothyroidism so i’m going to take a note about subclinical so patients who have a persistent tsh of greater than 10 with a normal t4 in it’s most likely that they’re going to follow the natural history of the most if ages 65 and i’ve especially with cardiac disease the tsh norm is actually ranges and i’ll get to management

In a second but you could actually let their adverse effects in terms of metabolism and cardiac effects and all that so if a recheck those people in three to six months depending on the clinical by saying this but considering checking at epo antibody to see if this is hashimoto’s is going to be kind of correlated with that tpo antibody but case of like you’re not sure what

Type of hypothyroid this is so in terms of next step is this a new or established diagnosis or lab value so they like i an autoimmune of vast majority absolutely what you’re gonna see massive again because it’s kind of outside the scope and i’m trying to keep this short if you had a radiation to your neck or surgery to your neck like a hyper on in a second you want to look

At the previous labs and then the clinical time you’ve seen it do they have other symptoms going on illnesses other lab abnormalities or sometimes i just don’t really match up is the majority of what i’ve seen in primary care he’s like you someone will back with the tsh that’s abnormal and their t4 is also is the tsh is high and people that’s the vast majority of people

And then if you find it it’s the the thyroid so i kind of just want to look at the whole picture and see and going on which the labs are kind of just not really matching like looking at people have hashimoto’s so drugs lithium good medication but a the rest of them are not really common at all interferon alpha interleukin 2 some other chemo therapeutic type of medications

And so if you have any kind primary care medications i would definitely check and see if there’s any i’m aware of rather so number one how high is the tsh and what is the free t4 cold intolerance fatigue constipation dry skin hair loss weight gain menstrual delayed dtrs deep tendon reflexes they may have gorder because you know graves the time to try to make it work more

It can become enlarged there are some cases is there some enlargement that on my thyroid exam it doesn’t feel enlarged or four steps to hypothyroid management so number one is overt wears a subclinical tsh with a low t4 or high tsh with a normal t4 and they have no symptoms and picture make sense or does it nandu you have to kind of look into those other for hipa thyroid in

Number four is monitoring the lab it’s labs in the back to jenelle for her we can proceed with management for tsh is less than 10 got fatigue she has had treatment in the not a new hypothyroid for her even though she’s a new patient we don’t have slide but we’re gonna start with 50 micrograms and recheck her labs in six anybody with a low persistently high tsh low functioning

Thyroid with a low t4 dosing i honestly go for standard dosing all the time either 25 or 50 micrograms 1.6 mike’s per kilogram per day of lean body weight so not on this patient’s bmi based on their but if you’re talking about a 70 kilogram person that’s a right out of the gate giving somebody that because i’ve seen people all over i actually a note about the 25 to 50 if

I have anybody 65 and up or cardiac and they’re younger and they have you know more than 65 and they have cardiac you’re gonna recheck the tsh in six weeks and that’s because of the normal range of 0.5 to 5 approximately doing in your lab again and it’s okay to would correct them to within that 5 range but i read that recently that that guideline that that’s kind of expert

Opinion but that’s something to think highly symptomatic and just kind of see like are we making progress here or not your clinical judgement whether it’s up or down and so if the tsh is still high if it’s like slightly high or 25 if it’s if it’s very high like it’s really just weeks and the 12 micrograms just comes on to the dosing honestly so if you’re less than that you

Have 25 50 75 88 100 112 125 i think a actually goes up to and so that’s really kind of excuse me up to you in your discretion and if bit more slowly and maybe choose that 12 if they’re getting close to their goal t4 hormone arm or thyroid i actually will not be able to pronounce the an advertisement is a bovine source pig thyroid as far as i understand it’s and prefer it

That way i find that it’s a really irregular dosing and a higher like pharmaceutical i mean it is but that’s a whole discussion but it’s just people will need both t3 and t4 but i’m gonna let that go to the endocrinologist like that question you can definitely kind of give them that answer of why you that’s absolutely totally fine and it doesn’t actually matter if it’s an

Empty that it’s on an empty stomach two hours before anything else but honestly and as long as it’s consistent it’s just more important that they’re doing it the same type of meals and then there may be settings things like nephrotic syndrome celiac disease certain medications phenytoin rifampin carbamazepine phenobarbital and pregnancy and i’m that is very important for

Fetal development and way outside the scope of um so let’s go back to janelle so um we did her thyroid management like i said back to normal so we’re still in the 15 micrograms for her so i just it’s really when you come in we just have these everyone has a risk for cognitive bias our t4 was still normal so she we had a mutual discussion workup for her pending on how she

Feels with the full six weeks until we recheck something i think about there i did an ultrasound for pyramid perimenopausal perimenopausal irma no definitely menopausal is really concerning but the obesity is one of the risk factors of endometrial hyperplasia and so you could endometrial ultrasound is a little bit more less invasive less uncomfortable so lining then we can

Consider monitoring or doing it endometrial biopsy i actually not that invasive it’s an invasive procedure but it’s not that was 169 systolic she really didn’t want to take any medications and she’s been is really gonna help her we had a discussion about pre diabetes and is doing a lot of work on her own but she’s hoping that the thyroid month because i really want to dig

Into more of the sleep apnea fatigue workup like the history questions you ask and the labs you could do and things like share with your mp friends so together we can reach as many new grads as to grab your copy of the ultimate resource guide from the new mp over at your inbox every week with notes from me patient stories more helpful insights for watching hang in there and i’ll see you soon

Transcribed from video
High TSH Levels: Lab Interpretation for New Nurse Practitioners By Real World NP