What Your Thyroid Does
Two major hormones that affect how your body works are made in your thyroid. These are called thyroxine and triiodothyronine .
Your thyroid controls things like how fast your heart beats and how quickly you burn calories. It releases hormones to control your metabolism .
Another important hormone your thyroid makes is called parathyroid hormone. This helps keep a healthy amount of calcium in your blood.
Hyperthyroidism, also known as overactive thyroid, can speed up your metabolism and cause unpleasant symptoms.
What Is Postpartum Thyroiditis
Postpartum thyroiditis, or inflammation of the thyroid after giving birth, affects 10% of women.3 It often goes undiagnosed because symptoms are much like the “baby blues” that may follow delivery. Women with postpartum thyroiditis may feel very tired and moody.
Postpartum thyroiditis typically happens in two phases, though not everyone with the condition goes through both phases:4
- The first phase starts 1 to 4 months after giving birth and typically last 1 to 2 months. In this phase, you may have signs and symptoms of hyperthyroidism because the damaged thyroid leaks thyroid hormones out into the bloodstream.
- The second phase starts about 4 to 8 months after delivery and lasts 6 to 12 months. In this phase, you may have signs and symptoms of hypothyroidism because the thyroid has lost most of its hormones or because the immune attack is over and the thyroid may recover later.
Is Hyperthyroidism The Same Thing As Thyrotoxicosis
Hyperthyroidism is a type of thyrotoxicosis. Hyperthyroidism happens specifically when your thyroid gland both produces and releases excess thyroid hormone. Thyrotoxicosis happens when you have too much thyroid hormone in your body in general. You could have too much thyroid hormone by taking too much thyroid medication, for example. This would be thyrotoxicosis, not hyperthyroidism.
A note from Cleveland Clinic
Getting a new diagnosis can be stressful. The good news is that hyperthyroidism is a manageable and treatable condition. If youre experiencing symptoms of hyperthyroidism or have certain risk factors, such as a family history of Graves disease, be sure to contact your healthcare provider. They can have you undergo some simple tests to see if your thyroid is making too much thyroid hormone.
Last reviewed by a Cleveland Clinic medical professional on 10/19/2021.
References
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Is This Thyroid Lab Testing Pattern Bad
The first thing you should know is that having a high TSH, even if accompanied by a normal T4, is never a normal sign.
A high TSH is a marker that the connection between your brain and your thyroid may not be functioning at 100%.
What do I mean?
In order to understand this concept, you have to understand how TSH functions in your body.
TSH is a hormone that is produced by the pituitary gland.
Its job is to act on your thyroid gland to tell your thyroid to produce more thyroid hormone.
This process is how your brain and your thyroid gland regulate thyroid hormones in your blood.
As thyroid hormones drop your TSH will rise to compensate to tell your gland to produce more.
This rise in TSH is almost always seen as an early and sensitive marker for thyroid dysfunction!
So, while TSH tells you how responsive your thyroid gland is to thyroid hormone it doesn’t give information on your free thyroid hormone levels.
Causes Of High Tsh Levels
Thyroid hormones operate on a negative feedback loop. Low thyroxine levels indicate to the pituitary gland to produce more TSH, but more TSH can further decrease thyroxine levels. Therefore, any issues that cause hypothyroidism, will in turn affect production from the pituitary gland.
One of the most common causes of hypothyroidism with a high TSH level is chronic autoimmune thyroiditis, also known as Hashimoto’s thyroiditis. White blood cells begin to attack the thyroid gland, which decreases the amount of thyroid hormone it produces.
Other things that affect T4 levels, ultimately affecting TSH levels, include:
- Hormonal changes from hormonal birth control or a shift in estrogen levels
- Medications that cause thyroid dysfunction, like amiodarone or tyrosine kinase inhibitors
- Injury to the thyroid gland from radiation therapy
- Partial or complete removal of the thyroid gland
While the causes of thyroid diseases are widely researched and understood, it is less clear what can cause the elevated TSH levels if the pituitary gland is the source of the issue. One possible cause of elevated TSH levels are TSH-secreting adenomas. These are tumors on the pituitary that independently produce TSH, stimulating the thyroid gland to produce T4 and T3. However, these tumors are rare.
Swelling of the pituitary gland can also cause malfunction and hormonal imbalance, potentially affecting TSH levels. However, the condition is rare and usually affects other hormones produced by the pituitary.
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What Are T3 And Ft3
Triiodothyronine is usually referred to as T3 and is one of the hormones that the thyroid secretes. Doctors from the American Association for Clinical Chemistry say that T3 is more active than the more abundant T4 and is a powerful thyroid hormone in the body. Free T3 is the amount of triiodothyronine that is not bound to protein and can still be used by the body. Doctors sometimes run tests for total T3 or just FT3 to check thyroid function.3
When Tsh Alone Is Not Enough
During diagnosis, most healthcare providers use the TSH test to evaluate thyroid function and determine the optimal course of treatment. There are times, however, when knowing one’s TSH may be insufficient.
For instance, free T4 in addition to TSH is usually tested if a healthcare provider suspects thyroid dysfunction due to disease of the pituitary gland or hypothalamus.
Likewise, if the TSH is normal, but a person still has symptoms of being hyperthyroid or hypothyroid, free T4 may be checked.
TSH is also not necessarily sufficient to monitor hypothyroidism during pregnancy T4 and free T4 are often recommended.
Depending on the clinical situation, other thyroid tests that may be done include , free T3, reverse T3, and thyroid antibody tests.
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In People Without Known Thyroid Disease
A high TSH in people who are not undergoing thyroid disease treatment usually indicates the presence of primary hypothyroidism.
This is by far the most common form of hypothyroidism, and it occurs because the thyroid gland produces an inadequate amount of thyroid hormones. The pituitary gland senses these low levels and increases the production of TSH.
An elevated TSH may also occur with normal thyroid function due to the presence of antibodies, proteins made by the immune system.
Is It Possible To Have A High Tsh And Normal T3 & T4
Yes!
In some cases, the serum T3 and T4 levels can be relatively preserved despite elevation in TSH levels.
Some people assume this is a reactive response but you must realize that serum concentrations of thyroid hormone do not necessarily reflect tissue levels of thyroid hormone.
Whats important is not the serum concentration but the amount of thyroid hormone that enters the cells and activates genetic transcription.
TSH reflects the tissue concentration of the pituitary gland, but it does not reflect the concentration of say your liver.
You can learn more about using the SHBG for this purpose in this guide.
Just realize for now that in order to get a complete picture of thyroid function in the body, you should evaluate TSH in the presence of other thyroid lab studies such as free T3, total T3, free T4, sex hormone-binding globulin, and of course thyroid antibodies.
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Nonalcoholic Fatty Liver Disease
Nonalcoholic fatty liver disease is a term that refers to conditions affecting liver of persons who drink little to no alcohol. The primary characteristic of this disease is excessive fat stored in liver cells, hence the name. Figures show NAFLD is the most prevalent type of chronic liver disease affecting 80 to 100 million people.
The specific cause of excessive fat accumulation in the liver is unknown, but different factors play a role such as overweight/obesity, high levels of fats in blood, high blood sugar, and insulin resistance.
He W. et al carried out a study which evaluated the relationship between NAFLD and hypothyroidism. The idea for the study stems from the theory that hypothyroidism plays a role in the pathogenesis of this disease. Scientists searched databases such as PubMed, EMBASE, China Dissertation Database for observational studies on the subject.
Their search yielded 13 studies and the final analysis demonstrated that both overt and subclinical hypothyroidism were significantly related to NAFLD. Scientists concluded that hypothyroid patients are at a higher risk of getting the nonalcoholic fatty liver disease, thus providing more evidence about the relationship between liver and thyroid.
If You Suspect That A Medication Is Causing Your High Tsh
If you suspect that a medication is contributing to your high TSH and low thyroid function, I encourage you to do two things.
- Watch my video that explains medications that alter thyroid levels leading to symptoms of being Thyroid overmedicated
- Have a serious conversation with your endocrinologist or your prescribing doctor regarding these drugs and the effects they are having on your thyroid levels.
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Normal Thyroid Levels: Typical Numbers & How Testing Works
Your thyroid gland is an essential part of your endocrine system that secretes hormones that regulate metabolism, heart function, digestion, muscles, brain development, and bone health.
In this article, well talk about typical thyroid hormone levels, which tests are important, and what to do if you have hypothyroidism.
How Are Thyroid Problems Prevented And Treated
If your cancer treatment could affect your thyroid gland, your doctor will check your thyroid hormone levels before treatment begins. You may be able to take medicine before some cancer treatments to help prevent thyroid problems.
Treatment for your thyroid problems depends on if you have an overactive or underactive thyroid. You may need to talk with an endocrinologist, which is a doctor who specializes in treating problems with hormones, glands, and the endocrine system.
Underactive thyroid . The treatment for an underactive thyroid is artificial thyroid hormone medication, given as a pill you swallow. You take the pill at the same time every day. Usually, you will need to take this pill daily for the rest of your life.
Sometimes, low thyroid function after radiation therapy can get better. If so, you would stop taking medicine when your thyroid gland starts to work well again.
Overactive thyroid . Treatment for high thyroid levels includes medication. If you have a non-cancerous nodule on your thyroid or thyroid cancer, treatment options include surgery or radioactive iodine treatment. Treatment destroys thyroid tissue so it cannot produce hormones.
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Cysts Or Nodules In The Thyroid Gland
Nodules or cysts in the thyroid gland can affect its function and cause too little T4 and T3 to be produced. This has the effect of increased secretion of TSH which can cause levels to increase above 4.0 mIU/L.
The journal Medical Clinics of North America reports that testing for high levels of TSH is essential in monitoring thyroid nodules. Blood serum tests for TSH are usually combined with ultrasound scans to check for cancerous cells in the thyroid. Doctors say that constant monitoring is essential because low T4 in the blood along with normal or high TSH can increase the risk that nodules become malignant.16
Symptoms Of A Thyroid Issue
What are the symptoms of a thyroid problem? The symptoms of a thyroid problem comes from hyperthyroidism or hypothyroidism, both caused by unbalanced thyroid levels. Thyroid disease symptoms include:
- Enlarged thyroid
Graves disease or Hashimotos thyroiditis can lead to dangerously high or dangerously low thyroid hormone levels, respectively. There are many triggers for Graves or Hashimotos.
Its crucial to know if a patients thyroid imbalance is due to Hashimotos or Graves disease these are autoimmune conditions with a significantly different root cause and treatment strategy than thyroid disease which is not autoimmune in nature.
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Newly Diagnosed With Hashimotos
There are also a several videos that will be very helpful for you to watch, if you are newly diagnosed or suspect you have Hashimotos.
The good news about early detection of Hashimotos is that when it is caught in time, there are many action steps that can be taken to influence the course of the disease and reduce the destruction and damage caused by the immune system- but you need to take action sooner than later and you need to realize that taking thyroid replacement is NOT going to stop your autoimmune disease.
It is only going to replace the low hormone levels.- I call this the topping off the gas tank approach.
I always tell patients, that it is not difficult to diagnose Hashimotos disease, but what is tricky is identifying what your individual autoimmune triggers are and then making the necessary lifestyle changes required to support the immune system and this goes way beyond just changing your diet and taking some supplements.
If you want more information educate yourself as much as possible about these autoimmune triggers.
Lets move on to another reason behind a high or elevated TSH.
Thyroid Hormone Production And Metabolism
In healthy persons, thyroid secretes about 100 nmol of thyroxine and 10 nmol of triiodothyronine each day.
The hormone T3 has a higher affinity and about ten times bigger efficacy than T4 for the nuclear receptor, even though the latter is produced in significantly greater amounts than its counterpart.
Its also important to mention that T4 requires conversion and deiodination to T3 in order to become active biologically and exhibit its effects.
Metabolism of thyroid hormones is regulated by three groups of enzymes that together form a unique iodothyronine-seleno-deiodinase enzyme system. These particular enzymes convert T4 to T3, conversion of rT3 and T3 to T2, and inactivation of T4 to rT3.
No, T2 isnt a typo it is a lesser known thyroid hormone which can suppress TSH at high doses, but it doesnt exhibit major manifestations of thyroid hormone activity.
The conversion process of T4 to T3 hormone in extrathyroidal tissues takes place in kidneys and the liver and it accounts for about 30% to 40% of the extrathyroidal production of T3. Production and metabolism of thyroid hormone is a complex process and the liver plays a huge role here.
About 5% to 10% of plasma T4 is extracted by the liver during a single passage. This particular value is significantly higher than it can be accounted for by free T4 level delivered to the liver. And according to Mendel et al, that means that a substantial amount of protein-bound T4 is available for uptake.
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Ways To Prevent High Cholesterol
You can prevent high cholesterol the same way you can help lower itby living a healthy lifestyle focused on a heart-healthy diet and exercise. Other strategies that can help prevent high cholesterol include:
- Quitting smoking
- Getting enough good quality sleep
- Limit alcohol intake
However, if you have familial hypercholesterolemia, you may not be able to prevent it. You can work with your doctor to detect it early and manage it to prevent complications.
Signs And Symptoms Of High Cholesterol
High cholesterol on its own doesn’t usually cause symptoms. People often don’t realize they have high cholesterol until they get tested. However, the complications that high cholesterol causes do. As arteries and other blood vessels narrow and blood flow is slowed or stopped, every part of your body can be affected.
Uncontrolled high cholesterol can lead to the following complications:
- Atherosclerosis, which is a buildup of fatty deposits in your blood vessels
- Carotid artery disease, which is narrowing of the blood vessels in the neck that carry blood from the heart to the brain
- Coronary heart disease, which is damage or disease in the heart’s major blood vessels
- Peripheral artery disease, which is narrowing or blockage of the vessels that carry blood from the heart to the legs
Symptoms of these complications can include:
- Fatty deposits of cholesterol visible from under the skin called xanthelasmas
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What Is Hypothyroidism
At the front of your neck lies the thyroid, a butterfly-shaped gland that makes the hormone T4. When released into the bloodstream, T4 converts to T3, the most active form of thyroid hormone. Having sufficient levels of these hormones is important because the thyroid helps regulate body temperature, metabolism, blood pressure, and heart rate.
Hypothyroidism occurs when the thyroid is underactive . It affects as many as five in 100 people. Symptoms of hypothyroidism include fatigue, cold intolerance, constipation, dry skin, hair loss, muscle weakness, and weight gain.
What Is It Used For
A TSH test is used to find out how well your thyroid is working. It can tell if you have hyperthyroidism or hypothyroidism in your blood. But a TSH test can’t show what is causing a thyroid problem.
If you take prescription thyroid hormone medicine because of hypothyroidism or because you had your thyroid removed, you’ll have regular TSH tests to check your thyroid hormone levels. TSH tests are also used to monitor your thyroid hormone levels after treatment for hyperthyroidism.
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Hyperthyroidism And Graves Disease
Hyperthyroidism occurs when the thyroid gland produces too much thyroid hormone. This disorder occurs in about 1% of all Americans and affects women much more often than men. In its mildest form, hyperthyroidism may not cause noticeable symptoms however, in some patients, excess thyroid hormone and the resulting effects on the body can have significant consequences.
What Causes Thyroid Problems When You Have Cancer
Thyroid problems have many causes. Thyroid problems can happen on their own, whether you have cancer or not. They are more common as you get older. However, thyroid problems are also a common side effect of certain types of cancer and cancer treatment.
The types of cancer and cancer treatment that raise your risk of thyroid problems include:
Thyroid cancer. Removing part or all of the thyroid gland is the main treatment for this type of cancer. This causes thyroid hormone levels to drop. The hormones are replaced with medication.
Radiation therapy to the head, neck, or upper spine. This is one of the most common causes of thyroid problems after cancer treatment. Whole-body radiation can also cause thyroid problems.
Chemotherapy. Chemotherapy, especially in high doses before a bone marrow transplant , can cause thyroid problems.
Targeted therapy. Targeted therapy is a treatment that affects specific biomarkers in the cancer. Treatments called tyrosine kinase inhibitors, or TKIs, are an example of targeted therapies that can affect your thyroid gland. This includes the drugs sunitinib , sorafenib , imatinib , nilotinib and others.
Immunotherapy. Immunotherapy is a treatment that boosts your body’s natural defenses to fight cancer. Some immunotherapy treatments can affect your thyroid. Interferon-alpha is an example of an immunotherapy drug that may lower thyroid functioning.
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