What should I ask my endocrinologist at my 3 months follow up? My thyroid labs are good except TSH)

Question: What should I ask my endocrinologist at my 3 months follow up? (my thyroid labs are all good except TSH).

Answer: While TSH is one of the Thyroid markers we have to look at, it is not an accurate marker without having a context of other thyroid labs.

Concerning TSH alone, we've already touched upon it in other article:

NORMAL TSH BUT STILL SYMPTOMATIC?

https://www.yourendocrinehealth.com/post/normal-tsh-but-still-symptomatic

Today, however, we'd like to answer the question: "What to do if my thyroid labs are all good except TSH?".

Well, there can be various causes for this. Whether it's hypo or hyperthyroidism, low TSH is usually caused by one of the following:

• Taking too much medication

• Pituitary Dysfunction

• Euthyroid Sick Syndrome

When it comes to taking too much thyroid medication, for Graves' disease, it can lead to the low serum concentration of TSH, with normal free T3 and T4 concentrations.

You can read more about it in this article: https://www.ncbi.nlm.nih.gov/pubmed/16807224

In this scenario, You should ask Your doctor: "Is my dose of the medication correct?".

The doctor should be able to asses You based on Your symptoms. Keep in mind that symptoms of exogenous hyperthyroidism (caused by taking too much medication) differ from the endogenous one (Graves' disease).

What will be the symptoms of taking too much medication?

• Appetite change

• Difficulty sleeping

• Fatigue

• Heat intolerance

• Frequent bowel movements or diarrhoea.

• Heart palpitations

• Increased sweating

• Irritability

Now, it's very IMPORTANT to note that these symptoms are MILDER than these from endogenous hyperthyroidism.

But what about hypothyroidism, can it also happen?

Yes, it can also happen in hypothyroidism.

Taking too high dose of medications like levothyroxine, Synthroid, Armour Thyroid, Cytomel etc. can influence Your TSH level and lower it down.

Typical symptoms of this will be hypothyroid symptoms like heart palpitations, losing Your hair, anxiety, hot flashes etc.

Another, very common reason for Low TSH with other labs being in range, is Pituitary dysfunction.

Pituitary dysfunction will present with symptoms like

• Symptoms associated with a low TSH due to pituitary dysfunction include:

• weight gain

• hair loss

• fatigue

• appetite changes

• cold intolerance

*** Symptoms associated with low sex hormones like low libido, changes in Your menstrual cycle, vaginal dryness, painful intercourse, changes to breast size or volume and hot flashes.

The reason for these additional symptoms is because of the pituitary gland, which not only produces TSH but also other hormones like LH, FSH, Prolactin and many others.

If this is the case, then we recommend testing for homocysteine levels and cortisol levels.

The last scenario, in which You may have TSH variation is Euthyroid Sick Syndrome.

Most people can get away with a low TSH without long-term complications, but it’s best to avoid a suppressed TSH if at all possible.

If you are taking thyroid medication and your reverse T3 is that high and your TSH is that low then you are probably taking too much T4.

If that’s the case then you’ll want to try and adjust how much T4 and T3 you are taking. Preference should be placed on optimising free T3 over free T4 if necessary.

Euthyroid Sick Syndrome occurs when You put Your body under high stress and the organism reacts to "protect" itself.

Stress can be from chronic disease, work, trauma, social life, environmental or extreme dieting (usually low caloric intakes or lots of caffeine).

All of these things may result in suppressed TSH.

This condition may present with or without the symptoms. If present with symptoms, it will be similar to hypothyroid symptoms.

To sum up:

There can be various causes of low TSH with other labs being in range. We recommend You speak with Your doctor about Your symptoms and check other lab values.

The reason for this is: TSH alone is not enough to tell You what's wrong but just to indicate where can be the problem. TSH value is always in context to other lab values.

In some cases testing for other hormones like TRH, FSH, LH, ACTH or prolactin can be necessary while in other simple reduction of medication dose will be enough.