Hypothyroidism

Martina Feichter studied biology with an elective subject pharmacy in Innsbruck and also immersed herself in the world of medicinal plants. From there it was not far to other medical topics that still captivate her to this day. She trained as a journalist at the Axel Springer Academy in Hamburg and has been working for since 2007 - first as an editor and since 2012 as a freelance writer.

More about the experts All content is checked by medical journalists.

Underactive thyroid (hypothyroidism) is what doctors call a deficient production of hormones by the thyroid gland. The hormone deficiency slows down all metabolic processes in the body and reduces performance. Hypothyroidism is one of the most common metabolic diseases. Women are more likely to suffer from hypothyroidism than men. Here you can find out everything you need to know about the symptoms, causes and treatment of hypothyroidism.

ICD codes for this disease: ICD codes are internationally recognized codes for medical diagnoses. They can be found, for example, in doctor's letters or on certificates of incapacity for work. E89E06E03E00

Brief overview

Common symptoms: fatigue, weight gain, constipation, dejection, freezing
Investigations: blood test for thyroid values, ultrasound, scintigraphy
Treatment: L-thyroxine tablets
Attention: Check the hormone dose regularly (TSH value), correct treatment is particularly important during pregnancy
Specialist: internal medicine (endocrinology), gynecology (for pregnant women), general practitioner

Hypothyroidism: Symptoms

In the case of an underactive thyroid (hypothyroidism), the thyroid gland does not produce enough of the two hormones thyroxine (T4) and triiodothyronine (T3). They influence almost all metabolic processes in humans and are therefore vital. While a slight hypothyroidism usually causes hardly any symptoms, a severe hormone deficiency slows down almost all of the metabolic activity and causes severe symptoms.

General symptoms

Common symptoms of an underactive thyroid (hypothyroidism) include poor performance, poor concentration and tiredness. Disorders of consciousness, sense of direction and memory and an increased sensitivity to cold are possible symptoms of hypothyroidism. The reflexes can be slowed down and muscles are more prone to cramps.

Outwardly, an underactive thyroid can cause signs such as a swollen face with thickened lips and enlarged tongue, swelling around the eye sockets and thus narrowing of the eyelids. The skin can be cool, dry, rough, and thickened; sometimes yellowish discolouration occurs (storage of the carotene pigment!). In addition, an underactive thyroid can trigger hair loss and make the hair shaggy and dull. A rough, hoarse voice and possibly a goiter (goiter) are other possible symptoms - they are caused by the pressure of an enlarged thyroid gland on the nerves of the larynx.

An underactive thyroid can also cause the following symptoms:

Depressive mood
constipation
Weight gain without changing eating habits
Slow heart rate (bradycardia), enlarged heart, low blood pressure
Circulatory disorders with abnormal sensations (such as "pins and needles")
Menstrual cycle disorders in women
Restrictions on sexual desire (libido), fertility and potency (erectile dysfunction = impotence)

Sometimes an underactive thyroid changes blood values such as the amount of hemoglobin and red blood cells. While these parameters can decrease in hypothyroidism, cholesterol levels are often elevated. This can lead to premature hardening of the arteries (arteriosclerosis).

Hashimoto's thyroiditis - acquired hypothyroidism as a result of chronic inflammation of the thyroid gland - can also be associated with a decline in the gastric mucosa (chronic atrophic gastritis) and other autoimmune diseases.

Symptoms in the Elderly

In older people, the only symptoms observed in hypothyroidism are sensitivity to cold, poor performance or depression. It is not uncommon for such signs to be misinterpreted as signs of old age, dementia or depression, and the real cause - hypothyroidism - remains undetected.

Symptoms in Babies

Babies with congenital hypothyroidism show a sedentary lifestyle, weakened muscle reflexes and a reluctance to drink immediately after birth. Constipation and prolonged neonatal jaundice can also indicate neonatal hypothyroidism. If the hormone deficiency is left untreated, growth retardation, delayed mental development and speech development disorders will occur in the further course. This severe form of untreated hypothyroidism is called cretinism.

Latent hypothyroidism: symptoms

The symptoms listed, such as poor performance and poor concentration, tiredness, etc. apply to manifest hypothyroidism, i.e. hypothyroidism with a measurable deficiency of thyroid hormones and increased TSH levels. A different picture emerges for latent hypothyroidism: symptoms like those mentioned above do not occur here or only to a limited extent. Because with the "hidden" hypothyroidism, the concentration of thyroid hormones is not (yet) lowered, only the TSH value is increased.

Hypothyroidism: causes and risk factors

Superordinate centers in the brain - the hypothalamus and pituitary gland - control the production of thyroid hormones: The hypothalamus releases the hormone TRH. It stimulates the pituitary gland to release the hormone TSH. This in turn promotes the production of thyroid hormones.

Thyroid hormone production

Centers in the brain (hypothalamus and pituitary gland) are responsible for controlling the production of thyroid hormones. When the hypothalamus releases the hormone TRH, it stimulates the pituitary gland to release the hormone TSH. TSH in turn triggers the production of thyroid hormones.

The causes of an underactive thyroid can arise on any of the three levels: through disturbances in the function of the thyroid itself, through disturbances in the production of TSH in the pituitary gland, or through insufficient stimulation of the pituitary gland by the hypothalamus. Accordingly, doctors differentiate between different forms of hypothyroidism:

Primary hypothyroidism

Primary hypothyroidism is by far the most common form of underactive thyroid. The cause of the disease lies in the thyroid gland itself. The causes can be congenital or appear in the course of life:

Congenital hypothyroidism

Some children are born without a thyroid gland (athyroidism). In others, the thyroid is deficiently developed (thyroid dysplasia), or there are errors in the production of thyroid hormones. Even if a pregnant woman receives too high a dose of therapy for an overactive thyroid, the unborn child can develop an underactive thyroid.

Acquired hypothyroidism

Acquired hypothyroidism is in most cases the result of chronic inflammation of the thyroid gland. This so-called Hashimoto's thyroiditis is an autoimmune disease: the body produces special antibodies that destroy its own thyroid tissue. It can then no longer produce sufficient amounts of thyroid hormones. Why the body makes the antibodies is still unclear.

Acquired hypothyroidism can also be the result of previous medical treatment. Therapy for an overactive thyroid gland (hyperthyroidism) sometimes overshoots the target: both radiation with radioactive iodine and treatment with drugs against hyperthyroidism can disrupt hormone production so permanently that the overactive function becomes underactive.

Thyroid surgery (for example, goiter = goiter) can also lead to hypothyroidism if there is not enough healthy thyroid tissue left.

Sometimes iodine deficiency plays a role in the development of acquired hypothyroidism: the thyroid gland needs the trace element to produce thyroid hormones. Those who take in too little iodine with their food can develop an extreme iodine deficiency and, as a result, hypothyroidism.

Hypothyroidism - no special diet required

Three questions for

PD Dr. Joachim Feldkamp,
Thyroid expert, specialist in internal medicine
1
How do I recognize an underactive thyroid?

PD Dr. Joachim Feldkamp
The signs of an underactive thyroid such as tiredness, severe concentration disorders, weight gain, constipation, slow pulse and a tendency to freeze are rather unspecific. But if two or three of these symptoms persist at the same time over a period of at least two weeks, you should see a doctor.
2
When does treatment make sense?

PD Dr. Joachim Feldkamp
If the TSH value is above 10, there is definitely a subfunction. If, on the other hand, the TSH value is only slightly increased, i.e. between 4 and 10, and the patient has only mild symptoms, a follow-up check in one to two months makes sense. Treatment should only be started when the value is confirmed and symptoms are present.
3
Do you have to pay attention to your diet if you are underactive?

PD Dr. Joachim Feldkamp
Here in Germany, the iodine content in the normal diet is so low that there is no need to fear any effects. Even Hashimoto patients are allowed to use iodized table salt, go to the sea and eat sea fish. You should only avoid algae with a very high iodine content, as this can worsen the disease.
PD Dr. Joachim Feldkamp,
Thyroid expert, specialist in internal medicine
Head of the Clinic for General Internal Medicine, Endocrinology, Diabetology, Infectiology at the Bielefeld Clinic and 1st Chairman of the Advisory Board of Forum Thyroid e.V.

Secondary hypothyroidism

The cause of hypothyroidism is secondary hypothyroidism in the pituitary gland: it produces too little TSH, the hormone that stimulates the thyroid to produce hormones. The reason for this can be a tumor in the pituitary gland or its surgical removal or radiation. A traumatic brain injury can also damage the hypophyes. Secondary hypothyroidism is rare.

Tertiary hypothyroidism

Tertiary hypothyroidism, which is caused by the hypothalamus, is even rarer. It then produces too little of the hormone TRH, which ultimately regulates thyroid hormone production on its way through the pituitary gland.

Hypothyroidism - Incidence

About one percent of the population has an underactive thyroid. About one in 3,500 newborns is born with hypothyroidism. This is called primary congenital hypothyroidism.

In addition to these patients with overt hypothyroidism, there are also numerous people who have what is known as latent hypothyroidism: Their blood levels of thyroid hormones are normal, but their TSH is already elevated. This means that the thyroid gland only produces sufficient amounts of hormone when it is very strongly stimulated by the pituitary gland. Latent hypothyroidism can later develop into manifest hypothyroidism.

Hypothyroidism: examinations and diagnosis

Hypothyroidism - medical examinations

If hypothyroidism is suspected, the doctor will first ask you about the typical symptoms and then do a physical examination. He can, for example, feel the texture of your skin or feel the anterior neck region where the thyroid is located. So he can judge their size and consistency.

Laboratory values of thyroid hormones

Taking a blood sample is also important. One of the most important blood values for clarifying a suspicion of hypothyroidism is the TSH value. The concentration of this hormone in the blood reveals how strongly the thyroid gland has to be stimulated to produce hormones in order to produce sufficient thyroid hormones. If the thyroid is underactive, the TSH concentration in the blood is increased in most cases.

You can read more about hormonal thyroid levels in the article Thyroid levels.

Further examinations as part of the diagnosis of hypothyroidism will help in finding the cause of your hormone disorder:

Ultrasound examination: The size and nature of the thyroid gland can be determined using an ultrasound examination. Sometimes the doctor also takes tissue samples (biopsy) for analysis in the laboratory.
Scintigraphy: With scintigraphy, the doctor examines the thyroid function using radioactively labeled substances (radionuclides).
Antibody detection: In the case of chronic inflammation of the thyroid gland, antibodies against the thyroid tissue can be detected in the blood.

Ultrasound scan to diagnose hypothyroidism

In an ultrasound examination, the doctor can determine the size and composition of the thyroid gland.

Newborns are tested for hypothyroidism as part of the legally required early detection examination (U2). To do this, the doctor takes one or two drops of blood from the heel a few days after the birth, drips them onto a filter paper and uses this to determine the TSH value.

Hypothyroidism: Treatment

The hormone deficiency in an underactive thyroid can be compensated for by taking hormone tablets, which is usually lifelong. Doctors also speak of replacement or substitution therapy. If it is dosed correctly, the quality of life and life expectancy of hypothyroid patients are not restricted.

The drug of choice for hypothyroidism therapy is L-thyroxine (levothyroxine): This synthetic hormone acts like the natural thyroid hormone thyroxine (T4) and is partially converted in the body into the thyroid hormone T3. It must be taken in the morning on an empty stomach.

Treatment with L-thyroxine is started with a low dose and then slowly increased to the individual end dose. If the dose is increased too quickly or if the dose is overdosed, heart problems or other signs of an overactive thyroid may occur.

The final dose depends on the basal TSH value (it should normalize) and the subjective well-being of the patient. Therapy is usually checked once a year (more often in infants) by means of a blood test.

Hypothyroidism: Treatment of the Elderly

Elderly patients with hypothyroidism require less amount of L-thyroxine because the natural hormone levels in old age differ from those in younger years. For example, people over the age of 60 usually receive a levothyroxine dose that is 30 percent lower than younger adults.

Hypothyroidism: Treatment of Pregnant Women

During pregnancy, hypothyroidism must be checked regularly because the body needs more thyroid hormones during this time. Therefore expectant mothers with hypothyroidism receive an increased dose of L-thyroxine; otherwise, in the worst case, there is a risk of miscarriage or premature birth. If the tablets are discontinued prematurely, the unborn child can also suffer physical and mental damage, because the child's thyroid gland does not begin to synthesize thyroxine until the 12th week of pregnancy.

Hypothyroidism: Treatment of Children

Children with congenital hypothyroidism also have to take the missing thyroid hormone on a daily basis. If you start taking it within the newborn phase, the children develop mentally normally. However, if congenital hypothyroidism is not recognized and treated until the age of three to six months, permanent mental damage can be expected.

Treatment of latent hypothyroidism

In the case of latent hypothyroidism, treatment with L-thyroxine (in a low dose) is also usually initiated. This is to reduce the risk of early arteriosclerosis and infertility.

Hypothyroidism: Homeopathy

Especially with chronic diseases such as hypothyroidism, many patients hope for help outside of conventional medicine. But can hypothyroidism be treated homeopathically? Basically: In diseases that require substitution therapy, homeopathy reaches its limits.

However, homeopathy can be used in conjunction with conventional medical hypothyroidism therapy. For example, Graphites D12 is recommended for hypothyroidism with slowed metabolism, overweight and freezing despite normal room or outside temperatures. An experienced therapist can advise patients which homeopathic remedies can also support the conventional medical treatment of hypothyroidism.

Hypothyroidism: Prevention

The most common cause of an underactive thyroid is an autoimmune disease (Hashimoto's thyroiditis).In this disease, the body's immune system turns against its own thyroid. As a rule, this cause of hypothyroidism cannot be prevented.

It is different with the hypothyroidism caused by iodine deficiency. Eat a diet rich in iodine. Use iodized table salt and eat fish regularly. Many fish species naturally contain plenty of iodine. You can read more on the subject of diet rich in iodine in the article "Hypothyroidism - Nutrition".

Diet tips

If you have an underactive thyroid, there are a few important things to keep in mind about your diet. Because the hormone tablets are not compatible with all foods. For example, foods rich in calcium block the absorption of L-thyroxine from the intestine and thus change the hormone level in the blood. Other foods or beverages can also interact with the drug.

If the thyroid gland still has some residual function - and this is the case with many patients at least for a certain period of time - you should make sure that you get enough iodine with your food. Adequate iodine intake is also an important way of preventing thyroid enlargement, the so-called iodine-deficiency goiter.

How you can prevent hypothyroidism with the right diet, which foods are particularly rich in iodine and what you should pay attention to in the case of hypothyroidism that has been treated, read in the article Hypothyroidism - Nutrition.

Lose weight with hypothyroidism

People with an underactive thyroid often have a weight problem. This is because their metabolism is slower than in healthy people due to the lack of thyroid hormones.

This reduces the so-called basal metabolic rate, i.e. the amount of energy that the body needs at rest to maintain the body functions (e.g. body temperature, circulation, digestion). In addition, more water is stored in the tissue in hypothyroidism.

Nevertheless, it is possible to lose weight even with a thyroid function. The most important key to this is drug treatment with thyroid hormones. But the right balance between calorie intake and calorie consumption is also important.

You can find out what you should pay particular attention to in the article Hypothyroidism - Losing weight.

Hypothyroidism: disease course and prognosis

Hypothyroidism can be effectively treated by taking hormone tablets (substituted hypothyroidism). This treatment usually has to be continued for life. Patients who follow the therapy exactly can then lead a completely normal life. They are not restricted in their performance or life expectancy. Pregnancy is also quite possible for women with an underactive thyroid.

The situation is different if the thyroid has been untreated for years. Consequences such as increased cholesterol levels, hardening of the arteries (arteriosclerosis) and infertility are not uncommon.

Desire to have children with hypothyroidism

A disturbed function of the thyroid gland is a common cause of an unfulfilled desire to have children. About every tenth couple is childless for this reason. Because the hormones of the thyroid gland have a variety of effects on the metabolism and thus also on the gonads and sexual function. In women, a malfunction of the thyroid gland can interfere with egg maturation and the menstrual cycle, among other things.

This does not require a fully developed hypothyroidism with a detectable hormone deficiency. Studies have shown that even latent hypothyroidism makes getting pregnant more difficult, in which only an increased TSH value can be detected.

You can find out what your doctor can examine in connection with the thyroid gland if you cannot become pregnant and what treatment options are available in the article Hypothyroidism - the desire to have children

Prognosis in children with congenital hypothyroidism

If the doctor recognizes congenital hypothyroidism immediately after birth and treats it, the children develop normally. If therapy is initiated too late, only the short stature can still be positively influenced. The brain damage and mental development disorders caused by an underactive thyroid, however, persist.

Additional information

Book recommendations:

Treating hypothyroidism successfully: ways out of a low mood, weight in balance. No more tired, limp and pale! (Dr. Andrea Flemmer, 2017)

Hypothyroidism, Hashimoto and hormones. The step-by-step guide to better treatment: Basic book on the thyroid gland (Irene Gronegger, 2015)

Guideline:

S2k guideline "Diagnostics, therapy and follow-up of primary congenital hypothyroidism" of the German Society for Pediatric and Adolescent Medicine and the German Society for Endocrinology (as of February 2011, in revision)