Introduction.
During health checkups or blood tests, you may be told that your TSH level is low.
When TSH levels are low, the first thing to consider is that thyroid hormones are present in high levels in the body. The most common diseases are Graves' disease, but thyroid inflammation and medications, pregnancy, and other factors can also be involved.
Since the cause cannot be determined based on the TSH level alone, it is necessary to look at the thyroid hormone levels and any associated symptoms.
The relationship between thyroid hormones and TSH
The thyroid gland is located in front of the neck,Thyroid hormonesIt is an organ that is being made.
Thyroid hormones regulate the body's metabolism and also affect heart rate, body temperature, energy consumption, and the function of the gastrointestinal tract.
Thyroid blood tests mainly check the following:
- FT4: The main thyroid hormone secreted by the thyroid gland
- FT3: Thyroid hormones that act more strongly in the body
- TSHA hormone secreted from the pituitary gland in the brain that regulates the function of the thyroid gland.
TSH stimulates the thyroid gland to produce hormones, but when thyroid hormones are increased enough, the secretion of TSH is suppressed.
In other words,
- Thyroid hormone increases → TSH decreases
- Thyroid hormone levels decrease → TSH levels increase
There is a connection like that.
Therefore,When you see a low level of TSH, first check to see if the thyroid hormone is not excessive.
The main causes of low TSH levels
Graves' disease
The most common cause of low TSH levels isGraves' diseaseです。
In patients with Graves' disease, the immune system is abnormal, causing the thyroid gland to be overstimulated and producing excess thyroid hormones.
The diagnosis includes tests for FT4 and FT3, as well as antibody tests related to B-cell autoantibodies and thyroid echography. Swelling of the thyroid gland and eye symptoms may also be present.
Non-painful thyroiditis and subacute thyroiditis
When inflammation occurs in the thyroid gland, thyroid hormones may temporarily leak into the bloodstream, resulting in low levels of TSH.
painless thyroiditisAs the name suggests, it often does not cause neck pain and can also occur after childbirth.
Meanwhile,subacute thyroiditisIn that case, it may be accompanied by neck pain and fever.
Both conditions have different causes and often improve over time, so it is important to distinguish between the two.
Thyroid nodules
Part of the nodules that form in the thyroid gland may eventually begin to produce thyroid hormones on their own.
In this case, thyroid hormones increase and TSH decreases.
We check for the presence of nodules using thyroid echography, and if necessary, we perform additional tests.
Effects of medication and pregnancy
If you are taking thyroid hormone medications, the amount of the medication may cause a decrease in TSH. Additionally, some medications can also affect thyroid function.
Even in early pregnancy, TSH may decrease due to hormonal changes associated with pregnancy.
The medication regimen and the possibility of pregnancy are also important information to consider when determining the cause.
Symptoms associated with high levels of thyroid hormone
When thyroid hormones are excessive, the body’s metabolism becomes too active, resulting in:
- Palpitations, rapid pulse
- Hand tremors
- Hot-tempered and sweat increases
- Weight loss
- Tired easily
- Diarrhea and the number of bowel movements increase
- Uncomfortable and irritable
Symptoms such as these may be observed.
However, in cases where the abnormality is mild, even if TSH is low, you may not experience any symptoms at all.
There may be cases where only TSH is low.
Even if TSH is low, FT4 and FT3 may still be within normal range. This condition is calledSubclinical hyperthyroidismIt is called
In mild cases, instead of treating it immediately, it may be necessary to wait a certain period of time and have a re-examination performed.
In addition, since TSH levels can temporarily drop due to severe illness or acute illness, it is also important not to make a judgment based on a single test result.
In rare cases, pituitary gland problems may also be the cause.
Just because TSH is low, it doesn’t necessarily mean that there is an excess of thyroid hormones.
In rare cases,When the function of the hypophysis that produces TSH declines, both TSH and thyroid hormones decrease.There are times when
In such cases, the approach is different from that of common hyperthyroidism, and therefore professional evaluation is required.
Tests when low TSH levels are noted
If you are told that your TSH is low, first check your FT4 and FT3 levels to see if your thyroid hormone levels are actually elevated.
Furthermore, if necessary,
- Antibody tests related to bashed disease
- Thyroid ultrasound
- Re-testing of thyroid hormones
- Medication intake and confirmation of pregnancy
We will do things like:
If FT4 or FT3 is high, or if you experience symptoms such as palpitations, trembling hands, or weight loss, we recommend that you have a detailed examination for thyroid disease.
Ikiridou Bridge Serra ClinicEndocrine Clinic of the ThyroidIn that case, we provide treatment for low TSH levels, Graves' disease, and thyroiditis, among other conditions.
If you have been told that your TSH level is low during a health checkup or you are concerned that you may have bashed disease, please feel free to contact us.
summary
Causes of low TSH include Bathers disease, painless thyroiditis/subacute thyroiditis, thyroid nodules, medications, and pregnancy.
On the other hand, even if the thyroid hormone is normal, low TSH may be caused by other factors, or in rare cases, it may be related to abnormalities in the pituitary gland.
When low levels of TSH are noted, it is important to check FT4 and FT3 as well, and to consider the cause based on the combination of these two tests.
To the page on thyroid disease