Thyroid levels

introduction

The thyroid is an organ that weighs around 20-60 grams and is located under the larynx and surrounds the esophagus and the vessels supplying the head. Despite its small size of only 3x2x11 cm on average, the thyroid gland plays an important role in the body. Via a complicated control loop, the thyroid releases the hormones T3 and T4, too Triiodothyronine and Thyroxine called out. These two hormones are essential for controlling metabolic processes in the human body. If the “thyroid values” are determined, this means the determination of these two hormones. The thyroid gland is often the cause of various, unspecific symptoms. The wide variety of symptoms shows how profound the effects of fluctuations in thyroid levels are.

Symptoms

The symptoms depend on the type of Malfunction from. Are the thyroid levels too high, one speaks of an overactive thyroid, or also Hyperthyroidism. Are the thyroid levels too low, is it an underactive thyroid (Hypothyroidism).

Because the symptoms are very unspecific other, more typical diseases are often clarified. However, it is Thyroid dysfunction and change in thyroid levels by a great deal common clinical picture, the diagnosis of which has now become very easy, so that the disease is usually recognized relatively quickly.

Which thyroid levels are normal?

Depending on which of the thyroid hormones you are looking at, there are different reference ranges that limit the normal range. However, it should be noted that certain patient groups, such as pregnant women or children, may also have deviating normal ranges. This is especially true for the regulation hormone TSH, which should be between 0.5 and 2.0 mU / L (milli units = thousandths of a unit per liter).

In pregnant women, values ​​between 0.1 and 3.0 can be normal, depending on the month. In children, too, higher values ​​are sometimes to be regarded as normal.

TSH is also the most important and most informative marker of thyroid function. Unfortunately, some laboratories still work with outdated reference values. In the course of the iodine supply, which has improved significantly over the last few decades, an adjustment has been made for the TSH. While values ​​up to 5 or 6 were accepted as normal in the past, these should now be viewed as clearly excessive and thus as a sign of a functional disorder. Unfortunately, not all doctors are up to date with this. It is therefore perfectly legitimate to speak to the treating doctor about this issue if you have any concerns.

If the TSH is above or below the normal range, the thyroid hormones T3 (triiodothyronine) and T4 (tetraiodothyronine or thyroxine) are usually determined. As a rule, these are determined as free (i.e. not bound to transport proteins) hormones. The free T3 (fT3) should be between 2.6 and 5.1 pg / ml (trillionth of a gram per milliliter) and the fT4 between 10 and 18 ng / L (billionth of a gram per liter). It should be noted, however, that different units are used in some cases, which means that the numbers for the normal range may turn out differently.

In the best case scenario, special values ​​such as thyroid antibodies should not be detectable at all. However, some healthy people also have these in their blood without any negative effects or treatment being necessary.

You might also be interested in: Hyperthyroidism in pregnancy

Thyroid levels too high - where does it come from and what to do?

If the thyroid levels are too high, the first thing to do is to stay calm. A variety of possible conditions can cause it, but in most cases there are good treatment options available. An increase in the usual thyroid values ​​generally suggests a benign disease.

First of all, it depends on which thyroid levels are elevated. If the thyroid hormones T3 and T4 (thyroxine) are increased, there is an overactive function. The thyroid regulating hormone, TSH, is then mostly low.

You might also be interested in this topic: Thyroid levels too high

At a Subfunction accordingly, in most cases the constellation is reversed, that is, here the TSH increased is and T3 and T4 are decreased. This is because more TSH is made to make the thyroid work harder, but it cannot make enough hormones. Depending on the type of dysfunction, different diseases can be the cause.

A hypofunction that occurs in adulthood is in most cases thyroid disease Hashimoto underlying. This is treated with the replacement of the thyroid hormones in the form of Tabletstaken daily.

Two diseases are common in overactive people. On the one hand, the so-called Thyroid autonomywhich can occur especially in older patients. There is uncontrolled production of hormones by part of the thyroid gland. As therapy either the Thyroid Removal take place through an operation or there is a targeted one Irradiation from the inside through the so-called Radioiodine therapy.

Elevated thyroid hormone levels can also be due to a Graves disease indicate. This condition can also occur in younger people. Typical signs are bulging eyes. In addition, there are usually special thyroid values ​​(antibody), which are additionally determined in suspected cases. If Graves' disease is diagnosed, treatment usually starts with Tabletsthat slow down the increased thyroid function (for example carbimazole). In many cases the disease is cured after a few months. Otherwise, the therapy alternatives already mentioned remain Radioiodine therapy or the surgery.

Symptoms of an overactive thyroid are general: restlessness, nervousness, profuse sweating, increased body temperature, weight loss or a cachectic, i.e. emaciated, appearance. In addition, there are cardiac arrhythmias, a high pulse, and possibly hair loss and even baldness. Not all symptoms have to be present at the same time, usually not all of them occur. To assess any thyrotoxic crisis will the Burch-Wartofsky score used. It is intended to provide information on whether a derailment thyroid control is present.

Due to the complex relationships and the multitude of possible causes, the doctor will advise the patient accordingly and, if necessary, order further examinations to determine the cause of the increased thyroid values. In the next step, a possible therapy and alternatives can be discussed. Thyroid disease experts are on the one hand Nuclear medicine (Radiation medicine) and on the other hand Endocrinologist (Doctors for hormonal disorders). The way should first be to Family doctor lead, who issues a transfer if necessary.

What are the values ​​for an underactive thyroid?

The first noticeable value in the case of an impending hypothyroidism is usually a increased regulatory hormone (TSH). Even if there are no complaints yet, an underfunction can be recognized at an early stage. The doctor then speaks of one latent hypothyroidism.

If the hypothyroidism is very pronounced, the thyroid hormones are often too T3 and T4 decreased in the blood. Then there is a so-called manifest hypothyroidism in front. In many cases, this is accompanied by symptoms of underactive such as freezing, tiredness and weight gain. The most common cause is thyroid disease Hashimoto. In most cases, special thyroid values ​​in the blood are also increased. These are antibodies typical of Hashimoto such as TPO antibodies and TG antibodies.

In rare cases, hypofunction can also show up in a decrease in the TSH value. These too central hypothyroidism mentioned constellation occurs with a Damage to the pituitary gland, for example due to an inflammation in the mother after the birth of a child.

The Hypothyroidism symptoms differ from those of an overactive thyroid. Roughly speaking, from a symptomatic point of view, they constitute the exact one opposite: There is listlessness, weight gain, depression, tiredness, dry / rough skin and a slow pulse (Bradycardia). Hair loss and cold intolerance can also occur.

Which thyroid values ​​suggest Hashimoto's thyroiditis?

Hashimoto's thyroid disease most often leads to one Subfunction with accordingly humiliated Thyroid hormone levels T3 and T4 (Thyroxine). The thyroid regulating hormone (TSH) is mostly elevatedas the body tries to increase hormone production in this way. It can be too, though Beginning the disease also reversed to a mostly temporary hyperfunction come with elevated thyroid hormone levels and decreased TSH. Other special blood values ​​are decisive for the diagnosis of Hashimoto. These so-called Thyroid antibodies are determined by the doctor if he suspects Hashimoto's disease. In most of the sick, these are increased.

More about this topic can be found: Hashimoto's thyroiditis

root cause

The causes of an overactive thyroid can be different. To understand them, you first have to look at the thyroid's control system: the main task of the thyroid is to produce the two hormones T3 and T4. These are then released into the body (more precisely: into the body's blood vessels).

In turn, the production of T3 and T4 is controlled by a hormone called TSH. TSH is the thyroid stimulating hormone. As the name suggests, it stimulates them Thyroid gland, or in German "Thyroid". A high TSH value means a high production of T3 and T4.

But how do high TSH levels come about? This can happen naturally, for example, when the body thinks there is not enough T3 and T4. This is the cheapest case and can be quite normal in certain life situations or situations.

If the thyroid levels are too high, this can also have other, more serious causes: For example, one speaks of thyroid autonomy when part of the thyroid gland withdraws from the regulatory cycle and no longer reacts to the regulating TSH. Some gland cells of the thyroid gland therefore produce hormones by themselves and no longer listen to external signals. This naturally shoots up the T3 and T4 values, so the thyroid values ​​are much too high. To counteract hyperfunction, the production of TSH is reflexively reduced to zero in order to prevent the thyroid from producing. In the case of thyroid autonomy, as occurs in autonomic adenomas, this of course does not change the overactive function and the high thyroid levels. Extremely low TSH levels in the laboratory along with clinical symptoms like restlessness and nervousness represent the classic picture of an overactive thyroid, too Hyperthyroidism, dar.

However, an overactive thyroid can also have other causes: especially in Iodine deficiency areas In earlier years giant thyroid glands developed, some of which were 100 times their normal size. Colloquially, this phenomenon was called "Goiter", Nowadays the term" goiter "is more commonly used. But how did it happen? The thyroid gland needs iodine to produce its two hormones T3 and T4. To be precise, 180-200 micrograms per day (0.18-0.2 milligrams) for adults and adolescents. Even this small amount could not previously be achieved in many iodine-poor areas.

More about this topic can be found: Iodine deficiency

In response, the thyroid needs her volume enlarge in order to achieve the necessary thyroid levels with more cells. If you suddenly give a goiter patient a lot of iodine, for example in the form of medication or iodinated contrast agent, so it comes to a firing of all thyroid cells and thus to immediate Hyperthyroidism. Therefore, the thyroid values ​​must always be checked before the administration of contrast media, otherwise there is a potential for them life-threatening metabolic situation arises. In the meantime, iodine is artificially added to many staple foods in Germany in order to enable an adequate supply even in iodine deficient areas. This is the best example iodized table salt.

The cause of an acquired hypothyroidism, or also Hypothyroidism, is, as already mentioned, the Iodine deficiency. It represents the most common cause of preventable mental worldwide Developmental disorders (Retardations) in children. If there is no substitution of iodine, the thyroid gland continues to grow, with the hope of producing sufficient thyroid hormones with more tissue. However, even with growth alone, the low thyroid values ​​cannot be compensated for in the long term, so that a deficiency or hypothyroidism occurs. Furthermore, the thyroid gland can be completely absent or only partially created at birth. This is noticeable relatively quickly when the child's thyroid levels are too low.

From one secondary hypothyroidism one speaks when everything is fine with the thyroid gland, but that stimulating hormone TSH is not produced sufficiently by the pituitary gland in the brain. So hyperthyroidism and hypothyroidism can merge and are mutually dependent.

therapy

The therapy of hyperfunction is principally carried out with thyreostatics. This is the name given to drugs that reduce the production of thyroid hormones when the thyroid levels are too high. Became a normal, say "euthyroid“Once the metabolic level has been reached, further therapy depends on the type of cause: An autonomous adenoma, which continuously produces thyroid hormones, can, for example, be surgically removed. However, there is a risk that individual parts will be overlooked or cannot be completely removed.

In general, complete removal of the thyroid gland is indicated for carcinomas, as these have a high mortality rate in the later stages. Thyroid surgery can only be carried out if the metabolism was previously euthyroid.

Radioiodine therapy is another therapeutic option: a radioactive iodine isotope is administered - usually orally - which is then absorbed by the thyroid cells, irradiating them from the inside and destroying them.

Read more on the subject below: Radioiodine therapy

The special thing about this therapy concept is that only the thyroid cells absorb the radioactive iodine and the rest of the body cells do not radioactive radiation to be hit. The Half-life of iodine is only 8 days. In other words, in 8 days the radiation has already halved. For the patient, however, this also means that after ingestion they will protect their fellow human beings for at least 48 hours in one Radiation protection bunker have to stay.

An outdated method, which goes back to the American endocrinologist Henry Plummer, is the "plumming". In the case of an overactive thyroid, large amounts of iodine are given (well over 200 micrograms per day), which is the Hormone synthesis and release and brings iodine uptake to a standstill for a few days. This method is used these days, however no more applied.

diagnosis

The diagnosis of thyroid values ​​is done in the laboratory by examining the blood. For this purpose, a small amount of blood (usually 10-30 milliliters) is taken from the patient and sent to the laboratory within a day. This is where the TSH is determined. The determination of the hormones T3 and T4 is much more costly and time-consuming and only takes place on special occasions. Since TSH usually represents the reciprocal value of the hormones, the determination of under- or over-function is also possible using TSH. The thyroid values ​​fluctuate strongly even in completely healthy patients, so that a reference range is relatively difficult to specify. A thyroid value outside the reference range does not necessarily mean that the patient is overactive or underactive. For TSH, the normal range is between 0.2 and 3.1 microU per milliliter. The thyroid itself is almost always examined by the attending physician using ultrasound if there is a suspicion of under- or over-function. Since ultrasound is a cost-effective, easy-to-use and non-invasive procedure, ultrasound has now become the “gold standard” in this context. Using ultrasound - or sonography - volume, size and any lumps or structural changes can be determined. For further clarification, a scintigraphy is usually carried out in which radioactively marked substances such as technetium or iodine isotopes are injected and then displayed with a scanner (a gamma camera). Enrichment of certain areas in the thyroid gland or completely empty fields are referred to as hot or cold nodes and can be an expression of an adenoma or carcinoma.

Read more on the topic: Cold lump on the thyroid gland

Do you have to be sober to determine your thyroid levels?

For the thyroid values ​​to be examined by the doctor, a small amount of blood is drawn through a vein, usually in the crook of the elbow. In contrast to certain other blood values, you have to do this for the determination of the thyroid values not sober be, that means you can eat and drink normally.

The only exception exists in people who already have Thyroid tablets take in. On the day of the blood test, these must be omitted before the blood is taken, otherwise they will falsify the measurement result. Only then should the tablet be taken. All other medications, such as those for blood pressure, should continue to be taken as usual.

Pregnancy and children

During pregnancy, the expectant mother needs more iodine than usual. At least 230 micrograms of iodine are recommended daily.
In addition, a slight enlargement of the thyroid gland is to be expected during this time - however, this is normal and due to the increased demands on the thyroid gland.

Read more on the topic: Diet in Pregnancy

Normal thyroid function is particularly important during pregnancy in order to ensure healthy and proper development of the child. Slightly different limit values ​​apply depending on the time of pregnancy. The most important hormone for determining function, TSH, should be between 2.5 and 0.1 in the first trimester of pregnancy. In the second trimester of pregnancy, on the other hand, the reference range is slightly higher with values ​​between 0.2 and 3.0. In the last three months of pregnancy, values ​​below 0.3 are considered too low. Here, too, the upper limit is 3.0.

If the values ​​differ, the thyroid hormones T3 and T4 are usually also determined. If these are also increased or decreased, there is a particular risk for the child and appropriate treatment, usually with tablets, should be given. If the TSH values ​​are too high, the thyroid antibodies that indicate Hashimoto's disease (TPO-AK and TG-AK) are usually also determined, as this is the most common cause of the TSH increase. Women who are already known to have a thyroid dysfunction should have their blood thyroid values ​​checked regularly during pregnancy.

A Hypothyroidism can be serious in children Developmental disorders cause.
Even during pregnancy there can be low thyroid levels as a result Premature births or Miscarriages come.
Therefore, the thyroid values ​​should always be clarified by the attending physician.

In children, it is essential to clarify an underactive thyroid as quickly as possible, otherwise developmental disorders such as Short stature, Malformations and in the worst case too Retardations (not age-appropriate mental development) can come.

The iodine deficiency is the most common cause of avoidable retardation in childhood worldwide. Children have to non-attached thyroid („Aplasia“) May take L-thyroxine daily for their entire life.
If it is not taken for several days, affected children experience symptoms such as Listlessness and depression wide.
These symptoms worsen if you continue to miss the dose. Monitoring thyroid levels is therefore particularly important during pregnancy and in children, as this sets the course for a healthy child development be asked.

What influence do the thyroid values ​​have on the desire to have children?

Women who want to have children and who have a thyroid dysfunction should be treated, since both an under and an overfunction can be responsible for the fact that this does not come true. If pregnancy does occur, if the mother's thyroid function is disturbed, there is a risk of it Malformations and developmental disorders of the child or even one of them Miscarriage comes. If there is a suspicion that a thyroid disorder may be present, women should therefore have their function clarified by a blood test with a doctor.

Even if no symptoms are noticed, as is often the case when only the regulatory hormone TSH is outside the normal range, the risks are increased. The determination of the thyroid values ​​in the blood is also uncomplicated and quick. If these are okay, it can alleviate potential worries. However, if they are not in the reference range, effective treatment is possible in most cases. The Man's thyroid levels have by the way no direct influence on the desire to have children.

prophylaxis

For prophylaxis, a regular controll the thyroid values ​​at Family doctor respectively. All that is required is a blood sample and an examination in the laboratory necessary. The results are usually available a few days later. Table salt, fish and dairy products contain a lot of iodine and should be consumed regularly. At the Donating blood the thyroid values ​​are contrary to popular belief Not checked.

miscellaneous

Goiter operations were much more common in the middle of the last century than they are now. To the partially ugly Surgical scars In Austria and Bavaria, the so-called "goiter band" was developed as part of the traditional costume to hide it. It was worn around the neck to hide the surgical scar. You can still see it today in some traditional costume parades.