Tsh for hypothyroidism range: Hypothyroidism: What is Hypothyroidism? Hypothyroidism Symptoms, Treatment, Diagnosis

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Hypothyroidism: What is Hypothyroidism? Hypothyroidism Symptoms, Treatment, Diagnosis

Hypothyroidism (underactive thyroid)

What is Hypothyroidism?

The thyroid gland is an important organ that regulates metabolism. The thyroid gland makes two forms of thyroid hormone – thyroxine (T4) and triiodothyronine (T3). Hypothyroidism is when the thyroid gland is not producing enough of these hormones. Primary hypothyroidism affects the whole body and may cause a variety of symptoms.

Having too little thyroid hormone can affect the whole body. The body’s normal rate of functioning slows, causing mental and physical sluggishness. Symptoms may vary from mild to severe.

What Are Signs and Symptoms Hypothyroidism?

Symptoms are different for each person. They are usually hard to notice and start slowly. They may be mistaken for symptoms of depression.

Here are the most common symptoms and signs:

Dull facial expressions
Tiredness and lack of energy (fatigue)
Not being able to handle cold
Hoarse voice
Slow speech
Droopy eyelids
Puffy and swollen face
Weight gain
Constipation

Sparse, coarse, and dry hair
Coarse, dry, and thickened skin
Hand tingling or pain (carpal tunnel syndrome)
Slow pulse
Muscle cramps
Joint pain
Sides of eyebrows thin or fall out
Confusion
Increased or irregular menstrual flow in women

How is Hypothyroidism Diagnosed?

At the UCLA Endocrine Center, you will meet with an endocrinologist who will ask about your past health and perform a comprehensive physical exam.

Blood tests can help diagnose hypothyroidism. Laboratory tests to determine thyroid function include:

What Causes Hypothyroidism?

The most common cause of hypothyroidism is an autoimmune disorder called Hashimoto’s Thyroiditis. This means your immune system starts to attack itself. It makes antibodies against the thyroid gland. The normal thyroid cells are overrun by white blood cells and scar tissue. Sometimes hypothyroidism occurs after treatment for an overactive thyroid gland. That may include radioactive iodine therapy or surgery. Hypothyroidism may also develop shortly after pregnancy.

A condition called secondary hypothyroidism can also sometimes happen. It’s when your pituitary gland stops working. The pituitary gland then no longer tells the thyroid gland to make thyroid hormones.

There are special considerations for women who have had thyroid disease in the past or currently, and who might be considering pregnancy or are already pregnant. Increased monitoring and adjustment of thyroid-related medications is recommended during this period for the health of both the mother and her baby. Special planning might also be necessary for women with a condition in which thyroid surgery and/or radioactive iodine are required.

Hashimoto’s Thyroiditis

Hashimoto’s thyroiditis is a type of inflammation of the thyroid gland that results from an autoimmune process. It is the most common cause of Hashimoto’s hypothyroidism in the U.S. However, some individuals with Hashimoto’s thyroiditis may never develop hypothyroidism and thus never have any symptoms.

How is Hypothyroidism Treated?

Treatment will depend on your symptoms, age, and general health. It will also depend on how severe the condition is.

The goal of treatment is to return your level of thyroid hormone back to normal. You may need to take medicine that gives you a dose of thyroid hormones. This dose may need to be changed over time. You will likely need to take this medicine for the rest of your life. You will need follow-up blood tests to make sure you are taking the correct dose of thyroid hormone replacement.

Endocrine Specialists: Located in Westwood, Encino, Torrance, Westlake Village, Thousand Oaks

Westwood

Endocrinology

Pediatric Endocrinology

Learn more about the UCLA Division of Endocrinology, Diabetes & Metabolism >

Staff

Encino

Endocrinology

Torrance (South Bay Endocrinology)

Endocrinology

John Tsao, Sr., MD
Endocrinologist
More >

Learn more about South Bay Endocrinology >

Westlake Village

Endocrinology

Learn more about Westlake Village Endocrinology >

Thousand Oaks

Learn more about Thousand Oaks Endocrinology >

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Phone: 310-267-7838

T4: What is a T4 Test? T4 Thyroxine Test

What is a T4 (thyroxine) Test?

Definition

A T4 test measures the amount of the T4 hormone in the blood. T4 is produced by the thyroid gland. T4 levels are important, because T4 increases numerous enzymes that produce energy for the body. Alternative Name: Thyroxine test.

How the test is performed:

Blood is drawn from a vein on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to swell with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding. For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

How to prepare for the test:

The health care provider may advise you to stop taking drugs that may affect the test (see “special considerations”). For infants and children: The preparation you can provide for this test depends on your child’s age and experience. For specific information regarding how you can prepare your child, see the following topics:

infant test or procedure preparation (birth to 1 year)
toddler test or procedure preparation (1 to 3 years)
preschooler test or procedure preparation (3 to 6 years)
schoolage test or procedure preparation (6 to 12 years)
adolescent test or procedure preparation (12 to 18 years)

How the test will feel:

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

This test may be performed as part of an evaluation of thyroid function. Thyroid function is complex and depends on the action of many different hormones:

Thyroid-stimulating hormone (TSH) is a secreted by the pituitary gland.
TSH causes the thyroid gland to produce two more hormones, T4 (thyroxine) and T3 (triiodothyronine).
Finally, TSH itself is stimulated by another hormone, thyroid-releasing hormone (TRH), which is made by the hypothalamus.

In people with normal thyroid function, having enough T3 and T4 inhibits both TSH and TRH, which prevents the body from making too much T3 and T4. Most T3 and T4 is transported by a protein called TBG (thyroxine binding globulin), but smaller amounts are found on prealbumin and albumin. When not bound to proteins, they are called “free” T3 or T4.

Normal Values:

Normal values vary among different laboratories. A typical normal range is: 4.5 to 11.2 mcg/dL (micrograms per deciliter).

What abnormal results mean:

Greater-than-normal levels of T4 along with low levels of TSH may indicate hyperthyroid conditions, such as:

Graves’ disease
toxic multinodular goiter
subacute or chronic thyroiditis
early Hashimoto’s disease
iodine-induced hyperthyroidism
germ cell tumors
trophoblastic disease

Lower-than-normal levels of T4 may indicate:

hypothyroidism (including Hashimoto’s disease, cretinism, myxedema, goitrous diseases, scleroderma, amyloid goiter, or hemochromatosis following neck irradiation for head and neck cancer)
malnutrition or fasting
illness throughout the body
use of certain prescribed medication, including dexamethasone, propranolol, lithium, iodine, methimazole, propylthiouracil, interferon alfa, interleukin-2, and amiodarone

Additional conditions under which the test may be performed:

hypopituitarism
hypothyroidism – primary
hypothyroidism – secondary
thyrotoxic periodic paralysis

Risks:

Risks associated with having blood drawn are slight:

excessive bleeding
fainting or feeling lightheaded
hematoma (blood accumulating under the skin)
infection (a slight risk any time the skin is broken)
multiple punctures to locate veins

Considerations:

Drugs that can increase T4 measurements include clofibrate, estrogens, methadone, amiodarone, and birth control pills. Drugs that can decrease T4 measurements include anabolic steroids, androgens, antithyroid drugs (for example, propylthiouracil and methimazole), lithium, phenytoin, propranolol, amiodarone, interferon alpha, and interleukin-2. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Request An Appointment

Phone: 310-267-7838

Hyperthyroidism: What is Hyperthyroidism? Hyperthyroidism Symptoms, Treatment, Diagnosis

Hyperthyroidism (overactive thyroid)

What is Hyperthyroidism?

Hyperthyroidism is a condition describing the overproduction of thyroid hormone from the thyroid gland.

What Are Signs and Symptoms Hyperthyroidism?

Symptoms are different for each person. Here are the most common ones:

Nervousness
Irritability
Sweating more than normal
Thinning of the skin
Fine, brittle hair
Weak muscles, especially in the upper arms and thighs
Shaky hands
Fast heartbeat (palpitations)
High blood pressure
More bowel movements than normal, diarrhea

Weight loss
Trouble dealing with the heat
Problems sleeping
Prominent eyes
Sensitivity to bright light
Confusion
Irregular menstrual cycle in women
Tiredness and lack of energy (fatigue)
Larger than normal thyroid gland (goiter)

How is Hyperthyroidism Diagnosed?

At the UCLA Endocrine Center, you will meet with an endocrinologist who will ask about your past health, including your medications and diet, and perform a comprehensive physical exam.

Blood tests can help diagnose hyperthyroidism. Laboratory tests to determine thyroid function include:

Thyroid Stimulating Hormone (aka TSH) helps indicate whether the thyroid is working correctly
Measurements of the two forms of thyroid hormone, T4 and T3
If indicated, measurements of specific antibodies targeted to the thyroid and its receptors

The workup may also include neck ultrasound to assess for thyroid nodules that could be overproducing thyroid hormone.

What Causes Hyperthyroidism?

Hyperthyroidism has several causes. These may include:

Graves’ Disease

This is an autoimmune disorder. It is the most common cause of hyperthyroidism. It happens when an antibody overstimulates the thyroid. This condition is most often found in young to middle-aged women. It also tends to run in families.

Toxic nodular goiter

This condition happens when one or more lumps (nodules) of the thyroid gland become too active. Health experts don’t know what causes this to happen. In most cases, the nodules are not cancer (benign). But in rare cases the overactive thyroid tissue is cancer.

Thyroiditis

This is a general term that refers to inflammation of the thyroid. Depending on the severity, thyroiditis may or may not produce any symptoms or need to be treated. The inflammation releases an excessive amount of thyroid hormone, leading to temporary hyperthyroidism. As the thyroid “burns out,” the thyroid then often becomes underactive.

Less common causes of hyperthyroidism include:

Taking too much thyroid hormone medicine to treat an underactive thyroid
Having too much iodine in your diet or in medicines, such as amiodarone
Having a noncancer tumor in the pituitary gland that makes your thyroid overactive

What are Causes of Thyroiditis?

Hashimoto’s thyroiditis (chronic lymphocytic thyroiditis)

Hashimoto’s thyroiditis is a type of inflammation of the thyroid gland that results from an autoimmune process. It is the most common cause of Hashimoto’s hypothyroidism (in which the inflammation results in an underactive thyroid gland) in the U.S. However, some individuals with Hashimoto’s thyroiditis may never develop hypothyroidism and thus never have any symptoms.

Infectious thyroiditis

Infectious thyroiditis is inflammation of the thyroid gland resulting from an infection in the thyroid. Patients with this will usually have neck pain, enlargement of the thyroid gland, and symptoms of an infection, such as fever and generalized body aches.

Painless thyroiditis

Painless thyroiditis is an inflammation of the thyroid gland in which there is a short period of both hyperthyroidism and hypothyroidism. The thyroid gland is not painful. Both usually resolve without treatment. Painess postpartum thyroiditis refers to this disorder when it occurs in women who were recently pregnant.

Drug-induced or radiation thyroiditis

Inflammation of the thyroid gland may also occur in individuals who are taking certain medications, including amiodarone, lithium, and interferon. Radiation of the neck can also result in thyroiditis. The hyperthyroid and hypothyroid phases of thyroid inflammation can be managed usually with medications alone.

Fibrous thyroiditis (Riedel’s thyroiditis)

Fibrous thyroiditis is an extremely rare condition in which the thyroid becomes hardened from a significant inflammatory process in the thyroid that extends locally in the neck. Surgery may be required to treat this condition.

How is Hyperthyroidism Treated?

Treatment will depend on your symptoms, age, and general health. It will also depend on how severe the condition is.

Treatment may include:

Medicine. It can help lower the level of thyroid hormones in the blood.
Radioactive iodine. It comes in the form of a pill or liquid. It slowly destroys the cells of the thyroid gland so that less thyroid hormone is made.
Surgery. You may need to have all or part of your thyroid removed.
Beta blockers. These medicines block the action of the thyroid hormone on the body. That helps with rapid heart rate and palpitations.

Frequently Asked Questions

What are possible complications of hyperthyroidism?

If your hyperthyroidism is not treated, these complications may happen:

Thyroid crisis, when symptoms get worse because of stress or illness
Heart problems, such as an abnormal rhythm or heart failure
Weak, brittle bones (osteoporosis)
Pregnancy problems, such as miscarriage, early delivery, and preeclampsia or high blood pressure

Tips to help you prepare for your visit:

Know the reason for your visit and what you want to happen.
Before your visit, write down questions you want answered.
Bring someone with you to help you ask questions and remember what your provider tells you.
At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
Ask if your condition can be treated in other ways.
Know why a test or procedure is recommended and what the results could mean.
Know what to expect if you do not take the medicine or have the test or procedure.
If you have a follow-up appointment, write down the date, time, and purpose for that visit.
Know how you can contact your provider if you have questions.

Endocrine Specialists: Located in Westwood, Encino, Torrance, Westlake Village, Thousand Oaks

Westwood

Endocrinology

Pediatric Endocrinology

Learn more about the UCLA Division of Endocrinology, Diabetes & Metabolism >

Staff

Encino

Endocrinology

Torrance (South Bay Endocrinology)

Endocrinology

John Tsao, Sr., MD
Endocrinologist
More >

Learn more about South Bay Endocrinology >

Westlake Village

Endocrinology

Learn more about Westlake Village Endocrinology >

Thousand Oaks

Learn more about Thousand Oaks Endocrinology >

Request An Appointment

Phone: 310-267-7838

Q and A: TSH (thyroid stimulating hormone)

Home » Patients Portal » Thyroid Q&A » Q and A: TSH (thyroid stimulating hormone)

Q: Is the TSH (thyroid stimulating hormone) a good way to titrate my thyroid hormone therapy?

A: Yes, absolutely! Once you have been diagnosed with hypothyroidism and started on thyroid hormone therapy, the TSH blood test is the best way to monitor your thyroid hormone replacement. TSH is made in the pituitary and the blood levels reflect how your own body is responding to the amount of thyroxine in your blood. When thyroid hormone levels are low, the pituitary gland increases secretion of TSH and indicates that your thyroxine dose should be increased. If your TSH level is low, your thyroid hormone dose is excessive and should be reduced. In most patients on thyroxine replacement, the goal TSH level is between 0.5 to 2.5 mU/L. Patients who have had thyroid cancer are usually on higher doses of thyroxine and their target TSH level is lower than normal. A TSH blood test should be obtained at least every 6-12 months while you are on a stable thyroxine dose, and more often if your dose is changed. Your doctor will usually wait 6-8 weeks after a thyroxine dose adjustment to measure your TSH, when the levels of thyroxine have reached a steady state. If you are on thyroxine and planning a pregnancy, or are currently pregnant, you will need more frequent TSH monitoring and should contact your physician. Although TSH is the best test for most patients on thyroxine replacement, those who have pituitary disease or previous pituitary surgery or radiation, are usually followed with measurement of free thyroxine, rather than a TSH.

Take a look at our Patient Web Brochure Hypothyroidism to learn more about hypothyroidism and how it is treated.

Medical Disclaimer The information contained in or made available through the American Thyroid Association Website is not intended to replace the services of a trained health professional or to be a substitute for medical advice of physicians. The user should consult a physician in all matters relating to his or her health, and particularly in respect to any symptoms that may require diagnosis or medical attention. The American Thyroid Association makes no representations or warranties with respect to any information offered or provided within or through the American Thyroid Association Website regarding treatment, action, or application of medication.
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Mild hypothyroidism: Who should be treated?

What to do about mild hypothyroidism is a subject that has been studied and debated for years. Mild hypothyroidism is also called subclinical hypothyroidism. It doesn’t meet the standard definition of overt hypothyroidism. You may have no symptoms, and your thyroid function blood tests show a mixed picture.

Your free T4 level is normal, meaning your body is getting enough thyroid hormone. It is your TSH (thyroid stimulating hormone) level that is above the normal range, which indicates your thyroid gland has to work harder to pump out that thyroid hormone.

One worry about mild hypothyroidism is the potential link between untreated subclinical hypothyroidism and coronary artery disease. Results of research on whether subclinical thyroid disease causes heart problems have been conflicting. However, the condition has been associated with heart and blood vessel abnormalities, and some studies suggest that treating mild hypothyroidism can improve various markers of heart structure and function.

However, there are potential downsides to treating subclinical hypothyroidism. There is the risk of overtreatment, which might cause symptoms, such as feeling jittery and insomnia. Also, long-term overtreatment can lead to loss of bone density.

If your TSH level is elevated to between 4.5 and 10 mIU/L and your T4 is normal, you should be considered for treatment with thyroid medication, especially if you have symptoms of hypothyroidism, or you have a positive test for thyroid antibodies, a history of heart disease, or risk factors for atherosclerosis. If you aren’t treated, your doctor should continue to monitor your thyroid function with blood tests every six to 12 months to check for progression.

If your TSH level is higher than 10 mIU/L, you should start treatment, because you will develop symptoms of an underactive thyroid, even if you don’t have them now.

For information on thyroid function in older adults, buy Thyroid Disease: Understanding hypothyroidism and hyperthyroidism, a Special Health Report from Harvard Medical School.

As a service to our readers, Harvard Health Publishing provides access to our library of archived content.
Please note the date of last review or update on all articles. No content on this site, regardless of date,
should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

Underactive thyroid: Deciding whether or not to treat subclinical hypothyroidism – InformedHealth.org

Subclinical (latent) hypothyroidism means that the thyroid gland is still producing enough thyroid hormones. But some blood values may suggest the early stages of a hormone deficiency. Experts don’t agree on whether subclinical hypothyroidism should be treated. It’s not clear in which cases treatment would have advantages.

If you already have noticeable (“overt” or “manifest”) hypothyroidism, the thyroid is no longer producing enough thyroid hormones. Thyroxine is the most important of the thyroid hormones. It helps regulate many of the body’s functions to balance your metabolism. Too little thyroxine can cause a number of different health problems. The symptoms range from cold hands to physical weakness, difficulty concentrating and depression. Hypothyroidism can be treated easily by taking a tablet containing the thyroid hormone once a day. These tablets act to replace the thyroxine that is not being produced. This usually makes the symptoms disappear completely.

Because it doesn’t cause any symptoms, subclinical hypothyroidism isn’t noticeable. The TSH (thyroid-stimulating hormone) value is too high, but the thyroid is still producing enough hormones. This hormone is produced in the pituitary gland and acts as a trigger for the thyroid to start producing the thyroid hormones. TSH levels that are just a little too high may be the first sign of the early stages of hypothyroidism: The pituitary gland responds to lower levels of thyroid hormones by increasing TSH production to activate the thyroid.

It is estimated that about 5 out of 100 people have subclinical hypothyroidism. Slightly elevated TSH levels are usually detected by accident during a routine examination. But taken on their own they don’t pose any health risk. It’s also possible that TSH levels are high only temporarily, for example after intense physical activity. Experts don’t fully agree on how to decide when subclinical hypothyroidism should be treated.

How is subclinical hypothyroidism diagnosed?

Thyroid values like TSH are measured in blood tests. Because a single test can be misleading, a second test is usually done 2 or 3 months later. In both tests, the blood is taken at the same time of day because TSH levels can fluctuate over the course of 24 hours. Subclinical hypothyroidism is diagnosed when both TSH readings are high but the thyroid hormone thyroxine is still within the normal range.

Experts don’t agree on which TSH levels should be considered too high. Some suggest that TSH levels of over 2.5 milliunits per liter (mU/L) are abnormal, while others consider levels of TSH to be too high only after they have reached 4 to 5 mU/L.

Both children and teenagers as well as older people have somewhat higher TSH levels than middle-aged people. Because of this, thyroid specialists have been debating whether a higher threshold should be used for these age groups. Being severely overweight and certain medications can also increase TSH. TSH levels are likely to fluctuate more during pregnancy.

How does subclinical hypothyroidism develop?

The way that subclinical hypothyroidism develops depends on a number of different factors – including the TSH level: Slightly elevated TSH levels (between 5 and 10 mU/L) often return to normal on their own. But people who have highly elevated levels (over 15 mU/L) often develop symptomatic overt hypothyroidism within several months or years.

One study followed people with high levels of TSH over a period of two to three years. The participants didn’t have any symptoms or diagnosed thyroid disorders. They were divided into three groups depending on how high their TSH levels were. The study produced the following results:

Slightly elevated TSH levels (between 5 and 10 mU/L): Each year, 2% of the participants in this group developed overt hypothyroidism.
Moderately elevated TSH levels (between 10 and 15 mU/L): Each year, 20% of the participants in this group developed hypothyroidism with symptoms.
Highly elevated TSH levels (over 15 mU/L): Each year, 73% of the participants in this group developed overt hypothyroidism.

TSH levels that are slightly or only moderately elevated don’t necessarily need to be treated. Some people who have high TSH levels never even develop symptoms. It is also very common for TSH levels to return to normal in children and teenagers.

The probability that overt hypothyroidism develops from subclinical hypothyroidism is greater if the thyorid is enlarged and thyroid antibodies are detectable in the blood. And women generally have a higher risk than men.

Thyroid antibodies are usually a sign of a condition called Hashimoto’s thyroiditis. This autoimmune disease is the most common cause of hypothyroidism. But detecting thyroid antibodies in your blood is not a sure sign that you have an underactive thyroid.

Does thyroxine treatment have any benefits if your TSH levels are high?

Some doctors will advise you to start treatment immediately if you have subclinical hypothyroidism. This is because there is some evidence suggesting that your risk of cardiovascular disease might slightly increase over the long term if TSH levels are higher than 10 mU/L. This link has not been observed for slightly elevated TSH levels lower than 10 mU/L.

Only a few good-quality studies have looked into what advantages and disadvantages thyroxine treatment may have for subclinical hypothyroidism. The largest and best quality study done yet involved nearly 800 people over the age of 65. It wasn’t large enough to answer the question of whether thyroxine treatment lowers the risk of complications, though. There was also no evidence that treatment offered other benefits: People who didn’t use thyroxine developed symptoms of hypothyroidism just as rarely as people who took thyroxine.

There are no studies showing any advantages of treating subclinical hypothyroidism in children and teenagers. Sometimes young people have higher TSH levels because they are overweight, so treatment with medication is usually not a good idea.

Does thyroxine treatment have side effects?

No good-quality research is available on the side effects of treating subclinical hypothyroidism with thyroxine, but it’s generally considered to be a well-tolerated drug. Because the body usually produces this hormone on its own, there are no problems if the dose is correct. If it’s too high though, side effects can’t be ruled out. Possible side effects include heart problems like atrial fibrillation or a racing heartbeat.

Does treatment make sense during pregnancy

Sometimes subclinical hypothyroidism in pregnant women is treated. For this purpose, they are occasionally offered a diagnostic screening test. In Germany this is provided as a “individual health care service” (IGeL Leistung).

Some evidence suggests that subclinical hypothyroidism during pregnancy can increase the risk of miscarriage or premature birth. But there is no proof that treatment with thyroxine can lower this risk in women who have high levels of TSH or thyroid antibodies. The largest study yet doesn’t show any advantage of treatment with thyroxine in pregnancy, neither for the risk of a premature birth or miscarriage, nor for the child’s development.

Treatment: Yes or no?

People who have no symptoms and only slightly elevated TSH levels usually don’t need treatment. Many doctors don’t recommend treatment unless the TSH levels are very high (over 10 mU/L). Other factors may also play a role in the decision, such as how high your overall risk of cardiovascular disease is.

Treatment is sometimes recommended already starting at TSH levels of over 6 mU/L in people with high levels of thyorid antibodies (Hashimoto’s thyroiditis). That is done to prevent subclinical hypothyroidism from becoming overt hypothyroidism. There is hardly any research on whether treatment can achieve that goal.

Deciding whether to have treatment or not very much comes down to personal preference since so many questions are still unanswered. You might prefer to not take any hormones unless it is absolutely necessary – even though thyroxine treatment is considered to be quite safe when taken at the correct dose. Especially if you have no symptoms or just very mild symptoms and hardly notice any effect from the medication, it can be a challenge to keep taking the tablets on a daily basis.

Some people may believe things like exhaustion or constipation are symptoms of their subclinical hypothyroidism and because of this try out treatment – even though it’s not the thyroid causing their problems. Instead, their symptoms may have a number of other causes.

If they don’t go away with treatment, they are probably not being caused by an underactive thyroid. Then you could stop taking the medication after talking it over with your doctor.

Sources

IQWiG health information is written with the aim of helping
people understand the advantages and disadvantages of the main treatment options and health
care services.
Because IQWiG is a German institute, some of the information provided here is specific to the
German health care system. The suitability of any of the described options in an individual
case can be determined by talking to a doctor. We do not offer individual consultations.
Our information is based on the results of good-quality studies. It is written by a
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Subclinical Hypothyroidism: Deciding When to Treat

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Standards for the level of thyrsotropic hormone in the blood: current state of the problem | Samsonova

One of the most controversial issues in modern thyroidology is the question of the norms for the level of TSH in the blood [4, 10]. The interest in this problem is understandable, since it is well known that the determination of the TSH concentration in the blood is currently considered a reference test in the laboratory assessment of the functional state of the thyroid gland, which allows timely detection of any violation of its function, including at the stage of asymptomatic hyper- and hypothyroxinemia.Thus, an increase in the TSH content in the blood serves as the earliest laboratory sign of not only obvious, but also threatened thyroid pathology, especially thyroid insufficiency. In this regard, it is quite obvious that the verification of thyroid insufficiency largely depends on the upper limit of the TSH level in the blood. At present, it is generally accepted that the concentration of TSH in the blood of more than 4-5 mU / l indicates a decrease in the function of the thyroid gland.

This article is a continuation of the discussion devoted to the norms of the upper limit of the norm for the level of TSH in the blood, opened on the pages of both foreign and domestic journals.

The reason for the discussion was the recent recommendations of the US National Academy of Clinical Biochemistry to reduce the upper limit of the norm for the level of TSH in the blood from 4 to 2.5 mU / L [8]. The basis for making such decisions was the results of the NHANES-111 epidemiological study, which showed that when examining 13 344 people receiving adequate iodine prophylaxis, the TSH level in the blood above 2.5 mU / l was determined in no more than 5% of cases [11] … At the same time, the study did not include those population groups that could potentially have abnormalities in the functional state of the thyroid gland [11].Similar results were obtained in the European SHIP-1 study [18]. Thus, as a result of a survey of 1488 adults in Pomerania, no more than 5% of the TSH level in the blood was higher than 2.12 mU / l [18].

It should be noted that not only after the publication of the recommendations of the US National Academy of Clinical Biochemistry, but also long before that, articles began to appear in foreign literature indicating that adult patients with a TSH level in the blood of 2-4 mU / L, for a number of clinical signs and laboratory tests differ from the population with a TSH level in the blood below 2 mU / L.So, back in 1992 J. Staub et al. showed that a group of adults with an average TSH content in the blood of 3.0 ± 0.3 mU / l demonstrates a hyperergic response of TSH to stimulation with thyroliberin, which is known to indicate a decrease in the functional reserve of the thyroid gland [16]. According to the data of the Wickham study, in the group of persons with a TSH level in the blood above 2 mU / L, subsequently, overt hypothyroidism is more often diagnosed [17]. Finally, in adults, this level of TSH is associated with an increased risk of hypercholesterolemia [7, 9, 14], endothelial dysfunction [12] and miscarriage [15].According to our data, such a concentration of TSH in the blood in women of reproductive age is associated with hypoestrogenism. Thus, every 8th (12.5%) woman of reproductive age, in whom the TSH level in the blood was determined from 2 to 4 mU / L when assessing the functional state of the thyroid gland, had a reduced level of estrogen in the blood (the median estradiol in this group of women was 167 pmol / l), while in all women with a TSH level in the blood below 2 mU / l, the estradiol content is within the normal range (median estradiol 235.25 pmol / l; /> = 0.01) [5] …

Moreover, in pregnant women (the most vulnerable part of the population in terms of the formation of pathological conditions associated with hypothyroxinemia), the TSH level in the first trimester of gestation more than 2 mU / L is currently a recognized factor of increased risk of developing gestational hypothyroxinemia. So, according to our data, gestational hypothyroxinemia occurs in almost every 2nd pregnant woman with diffuse endemic goiter, having a TSH level in the first trimester of gestation from 2 to 4 mU / l (/> = 0.05) [2].

Thus, a similar level of TSH in the blood in adults is associated with a known spectrum of pathological conditions, which are currently recognized as a consequence of chronic hypothyroxinemia.

At the same time, it should be emphasized that all the accumulated knowledge and ideas about the clinical and prognostic value of the TSH concentration in the blood of more than 2, but less than 4 mU / l were obtained on the basis of a survey of the adult population. The following data make it possible to form an opinion on the significance, competence and expediency of isolating this particular range of TSH levels in the blood and in pediatric practice.So, according to the results of the study by D.E.Shilin (2002), children and adolescents (n = 114) with a basal TSH level in the blood above 2 mU / l (on average 2.57 ± 0.06 mU / l) , differ from children and adolescents (n = 475) with a basal TSH level below 2 mU / l (on average, 1.19 ± 0.02 mU / l) [6].

In 94.1% of children (p <0.05) of this group, there is a hyperergic response of TSH to stimulation with thyroliberin, which indicates a reduced functional reserve of the thyroid gland [6]. According to the data of the same author, such children and adolescents have significantly (/> = 0.03) higher concentrations of atherogenic lipid fractions, and adolescent girls with a similar level of TSH in the blood show signs of age-related immaturity of the uterus and gonads (p = 0.01) [6].In addition, such girls have a tendency to polymenorrhea (menstruation on average lasts 5.5 ± 0.3 days versus 4.7 ± 0.1 days in the group of girls with a TSH level in the blood below 2 mU / l; p = 0.01) and a lower level of estradiol in the blood (the average content of estradiol is 162 ± 23 pmol / l versus 239 ± 22 pmol / l in the group of girls with a TSH concentration in the blood of less than 2 mU / l; p = 0.05 ) [6].

According to our data, it is adolescent girls with a TSH level in the blood above 2 but below 4 mU / l that are most vulnerable in terms of the formation of functional disorders from the reproductive system.So, according to the results of our research, every 2nd (54%) girl with a similar level of TSH in the blood has menstrual dysfunction of the type of opsomenorrhea (while only 28% of girls with a TSH level below 2 mU / l, P = 0.032 ) [1].

So, in our opinion, today there are enough arguments in favor of the fact that the level of TSH in the blood from 2 to 4 mU / l in children also reflects the earliest in terms of appearance and the mildest in severity of thyroid insufficiency.

It is obvious that thyroid insufficiency in iodine-deficient regions has its own evolution.In our opinion, the evolution of thyroid insufficiency can be represented as follows: 1) normal level of free thyroxine and TSH level from 2 to 4 mU / l, there are no clinical signs of hypothyroidism; 2) normal level of free thyroxine and TSH level above 4-5 mU / l, there are no clinical symptoms of hypothyroidism; 3) a reduced level of free thyroxine and a TSH level above 4-5 mU / l in combination with clinical signs of hypothyroidism. The last two stages of thyroid insufficiency are well known and are classified as subclinical and overt hypothyroidism, respectively.

At the same time, today there is no single generally accepted term characterizing the level of TSH from 2 to 4 mU / l. This is understandable, since terminology issues are always the most difficult. In the English-language literature, the TSH level within the traditionally normal limits, but above 2 mU / L, is denoted by the following terms: “high-normal TSH” [14], “very mild thyroid failure” [15], “a lessened thyroid reserve” [15], “mildest form of subclinical hypothyroidism” [16]. We propose to use the term “minimal thyroid insufficiency” to denote a condition, which is reflected in a TSH level from 2 to 4 mU / l.In our opinion, it is he who most accurately characterizes the earliest in terms of appearance and the mildest in severity thyroid insufficiency.

At the same time, at a given level of TSH, the functionality of the thyroid gland should be assessed depending on its size. Thus, in persons without goiter, a slight increase in the level of TSH (2-4 mU / l) only indicates that the thyroid gland at normal size is unable to provide adequate production of thyroid hormones.In this group of people, a similar level of TSH reflects the readiness to activate compensatory mechanisms leading to an increase in the size of the thyroid gland and to the normalization of the level of thyroid hormones. Thus, in persons with normal sizes of the thyroid gland, this condition cannot yet be classified as a pathology, but should be considered as a borderline state.

In patients with long-standing goiter, this level of TSH indicates that an increase in the size of the thyroid gland did not lead to the elimination of hypothyroxinemia and, therefore, the required level of thyroid hormones was not achieved.Most likely, in this case, there was a decrease in the compensatory and functional reserves of the thyroid gland due to a slight genetic defect in morpho- or hormonogenesis. Even with mild congenital failure of the thyroid gland in conditions of insufficient iodine intake, the formation of a goiter will not lead to the normalization of the thyroid status, that is, to the elimination of hypothyroxinemia and, consequently, the risk of iodine deficiency diseases.

We are deeply convinced that the use of the term “minimal thyroid insufficiency” in the context in which it is presented in the article will not only not mislead readers, but, on the contrary, will help to understand the essence of the problem and present the evolution of thyroid insufficiency in iodine-deficient regions.

It should be noted that another, no less, and perhaps more important question of this discussion is whether people with a TSH level in the blood need therapy from 2 to 4 mU / l. Foreign and domestic authors consider the danger of expanding indications for verification of hypothyroidism and treatment of such a patient with levothyroxine preparations as a serious argument against the recognition of new standards for THG in blood [4, 10].

In our opinion, the TSH level in the range from 2 to 4 mU / L indicates only that in the region of iodine deficiency, the thyroid gland is able to maintain an ideal euthyroid state only under the condition of an adequate intake of iodine.It is quite obvious that in the absence of adequate iodine prophylaxis in regions even with moderate and / or mild iodine deficiency (i.e., in most of the territory of Russia), it is this degree of thyroid insufficiency that will continue to occur frequently and determine the formation of medico-socially significant iodine deficiency states. … Hence the conclusion that the overwhelming majority of people living in these conditions and having a similar level of TSH in the blood only need adequate iodine prophylaxis.Adequate iodine prophylaxis in most of them is able to maintain an ideal euthyroid state for many years of life.

Exceptions are 2 groups of persons. These are primarily pregnant women with a TSH level in the first trimester of gestation above 2 mU / L, that is, having a risk factor for the development of gestational hypothyroxinemia [2]. Considering the exceptional role of the normal maternal thyroxine level for the formation and maturation of the central nervous system of the unborn child and the need for rapid and effective correction of gestational hypothyroxinemia, today no one doubts and objections that pregnant women with a similar TSH level need treatment with levothyroxine drugs.In addition, it is required to prescribe levothyroxine preparations to persons exposed to other (except for iodine deficiency) strumogenic factors of the external environment or having more pronounced genetically determined defects in the morpho- or hormonogenesis of the thyroid gland. It should be emphasized that we are talking about extremely rare cases.

When deciding on the TSH level standards, modern double standards used to assess the functional state of the thyroid gland in untreated individuals and in patients receiving replacement therapy with levothyroxine drugs are somewhat surprising [3, 13].In this regard, another weighty argument in favor of narrowing the normal range for the TSH level in the blood is that the overwhelming majority of researchers recognize and do not raise objections to the TSH level values in the range from 0.5 to 2 mU / L as reflecting the euthyroid state of the thyroid gland. in patients receiving replacement therapy with levothyroxine drugs [3, 13].

So, the above data convince us that today there are more than enough arguments in favor of recognizing the fact that (in both adults and children) the TSH level from 2 to 4 mU / l reflects the earliest in terms of appearance and the mildest thyroid insufficiency in severity, namely, minimal thyroid insufficiency.

Narrowing the range of TSH levels in the blood from 0.5 to 2-2.5 mU / l and the early introduction of these standards into healthcare practice is a prerequisite for optimizing early diagnosis, prevention, treatment of hypothyroxinemia and, consequently, the elimination of iodine deficiency conditions in Russia …

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Thyroid stimulating hormone (TSH, thyrotropin, Thyroid Stimulating Hormone, TSH)

Study material
Blood serum

Method of determination
Microparticle chemiluminescence immunoassay

A pituitary hormone that regulates the function of the thyroid gland.One of the most important tests in the laboratory diagnosis of thyroid diseases. …

TSH is a glycoprotein with a molecular weight of about 28 kDa. It is synthesized in the anterior pituitary gland. It activates the production and secretion of thyroid hormones (thyroid hormones), initiates cell growth and mitotic activity of thyroid cells. The synthesis and secretion of TSH is stimulated by the thyrotropin-releasing hormone of the hypothalamus in response to a decrease in the level of circulating thyroid hormones. The level of TSH is in inverse logarithmic dependence on the concentration of T4: with an increase in the level of T4, the production of TSH decreases, with a decrease in the level of T4, the production of TSH increases compensatory, which helps to maintain the concentration of thyroid hormones at the required height.TSH secretion is influenced by various neuronal mechanisms and changes during sleep, temperature drop, nonspecific stress. For TSH, daily fluctuations in concentration are characteristic: the highest values of TSH in the blood reach by 2-4 a.m., a high level in the blood remains until 6-8 a.m., the minimum TSH values are at 17-18 hours. The reference values for TSH levels below are applicable for outpatients between 8 and 18 hours. The normal rhythm of thyrotropin secretion is disturbed when awake at night.

With clinically pronounced primary hypothyroidism (i.e., damage at the level of the thyroid gland, which leads to a decrease in its function), there is a significant increase in TSH levels against the background of low levels of thyroid hormones. In contrast, primary hyperthyroidism is associated with decreased or undetectable TSH levels and high thyroid hormone levels. Determination of the TSH level makes it possible to identify subclinical stages of thyroid diseases, when the concentration of thyroid hormones is still maintained by regulatory mechanisms within the framework of reference values.Usually, in a screening study of thyroid function, TSH is used as the only test or in combination with the determination of free T4.

Taking thyroxine preparations on the eve of blood sampling for research does not affect the TSH concentration. Normalization of the TSH level during replacement therapy of hypothyroidism with L-thyroxine drugs occurs slowly (over several weeks and months), since hyperplasia of thyrotrophs develops in chronic severe hypothyroidism.A paradoxical combination – a high level of TSH and a high level of free T4 – during this period is an artificially induced (iatrogenic) state. Repeated studies of the TSH level in order to control therapy should be carried out no earlier than 6 weeks after changing the dose or type of drug.

In secondary and tertiary hypothyroidism associated with pituitary dysfunction due to pathology of the pituitary gland and hypothalamus, significantly reduced levels of T3 and T4 are combined with a normal or slightly increased level of TSH, which in these cases has a reduced biological activity.Rare clinical cases of secondary hyperthyroidism may be due to TSH-secreting tumors.

Severe non-thyroid diseases can cause temporary changes in TSH concentration. The reason may be the use of drugs or the consequences of the disease itself. Usually there is a decrease in the level of TSH in the acute phase of the disease and a slight increase in the level during recovery. If necessary, in such cases, it is advisable to focus on the extended reference range of TSH (0.02-10 mU / L) and use the complex of TSH and T4 tests (or free T4).

Physiological changes in TSH concentration have been observed during pregnancy. High concentrations of chorionic gonadotropin, which has a certain structural similarity to TSH, are capable of stimulating the synthesis of thyroid hormones. In the first trimester of pregnancy, there is a temporary increase in the content of T4 and a decrease in the level of TSH. During the II and III trimesters, the TSH level returns to normal. An increased level of TSH in early pregnancy may indicate latent hypothyroidism in the mother, potentially dangerous for the development of the fetus.

Limits of determination: 0.0025 mU / l-100 mU / l

A pituitary hormone that regulates the function of the thyroid gland. One of the most important tests in the laboratory diagnosis of thyroid diseases.

90,000 Subclinical Hypothyroidism and Metabolic Syndrome: Basis for Drug Intervention | Ruyatkina

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