Brief overview
- Description:Enlargement of the thyroid gland, which may or may not be visible or palpable (colloquially: goiter).
- Causes: Iodine deficiency, thyroiditis – some autoimmune (e.g. Graves’ disease, Hashimoto’s thyroiditis), benign and malignant tumors of the thyroid gland, infestation of the thyroid gland by other malignant tumors, thyroid autonomy, certain substances in food and drugs, etc.
- Symptoms: sometimes no, sometimes visible/palpable enlargement of the thyroid gland, feeling of lumpiness, tightness or pressure in the throat, clearing of the throat or difficulty swallowing.
- Diagnostics: palpation, ultrasound, measurement of hormone levels in the blood, tissue sampling if necessary
- Treatment: medication, surgery or nuclear medicine (radioiodine therapy)
- Prevention: targeted iodine intake in certain life situations (pregnancy, growth phases, lactation), generally iodine-rich diet
Goiter: Description
The thyroid gland (med.: Thyroidea) is an important hormone gland of the body, which is located directly below the larynx. It produces the two hormones T3 (triiodothyronine) and T4 (thyroxine), which are important for the entire metabolism and circulation. It also produces the hormone calcitonin, which is involved in the regulation of calcium balance.
Size classification of goiter
Scales can be used to classify enlargement of the thyroid gland according to its extent. The World Health Organization (WHO) uses the following scale for goiter size:
- Grade 0: goiter detectable only on ultrasound
- Grade 1: palpable enlargement
- Grade 1a: palpable enlargement, but not visible even when the head is tilted backwards
- Grade 1b: palpable and visible enlargement when head is tilted backwards
- Grade 2: palpable and visible enlargement even with normal head posture
- Grade 3: very large goiter with local complications (e.g. obstruction of breathing)
Goiter: Causes and possible diseases
Goiter due to iodine deficiency
The thyroid gland needs iodine to produce the hormones T3 and T4. The trace element must be ingested regularly with food. However, in so-called iodine-deficient areas, which include Germany, the soil and water contain hardly any iodine. Food produced here is therefore low in the trace element. Anyone who does not compensate for this in their diet, for example by using iodized table salt, can develop iodine-deficiency goiter:
Goiter due to inflammation of the thyroid gland
Inflammation of the thyroid gland (thyroiditis) can also lead to goiter. In this case, the cells of the hormone gland do not multiply or enlarge, but the tissue swells due to inflammation. Causes include infections with bacteria or viruses, injuries to the thyroid gland, or radiation therapy to the neck region.
However, thyroiditis can develop as a result of certain medications or after childbirth. In such cases, faulty reactions of the immune system (autoimmune reactions) are considered to trigger the inflammatory processes. Autoimmune thyroiditis also occurs in chronic forms of thyroiditis – Hashimoto’s thyroiditis and Graves’ disease:
In Graves’ disease, antibodies are formed that dock onto certain receptors in the thyroid gland that are actually responsible for recognizing TSH. These misdirected antibodies have the same effect as TSH and thus stimulate the thyroid gland to produce excessive T3 and T4 and to grow more – a goiter forms.
Goiter due to tumors
Benign and malignant tumors of the thyroid gland can cause goiter through the uncontrolled proliferation of degenerate cells. In addition, metastases from other primary tumors can become lodged in the thyroid gland, leading to enlargement. In some cases, the cause of a goiter is also a tumor in the pituitary gland, which results in increased production of TSH and thus indirectly causes a goiter.
Goiter due to drugs and other substances
Certain substances in foods (such as thiocyanate) can also be considered as goiter triggers.
Other causes
Sometimes goiter is the result of so-called thyroid autonomy. In this case, the thyroid gland produces hormones uncontrollably.
Rarely, peripheral hormone resistance is the cause of goiter. In this case, the thyroid hormones T3 and T4 cannot exert their effect in the target cells of the body tissue. Subsequently, more TSH is produced via a control circuit, because the body tries to correct the problem with the increased production of thyroid hormones. The increased TSH levels cause a goiter.
Other causes of goiter include altered thyroid enzymes, cysts in the thyroid gland, bleeding after injury to the thyroid gland, and hormonal changes during pregnancy, puberty, or menopause.
Manifestations of goiter
A goiter can be classified not only by its size, but also by other criteria:
- by nature:A struma diffusa is a uniformly enlarged thyroid gland whose tissue appears homogeneous. In contrast, in a struma nodosa, the thyroid gland has one (struma uninodosa) or several (struma multinodosa) nodules. Such nodules can potentially produce thyroid hormones and even do so independently of regulation via TSH (autonomous nodules). They are then referred to as warm or hot nodules. Cold nodules, on the other hand, do not produce hormones.
If malignant changes occur in an enlarged thyroid gland, this is also referred to as a malignant goiter. Bland goiter, on the other hand, is inconspicuous in terms of tissue structure and hormone production (neither malignant nor inflammatory, normal thyroid function).
Goiter: Symptoms
A small goiter is often not noticed at all by the affected person; it neither hurts nor restricts the patient, nor is it visible or palpable. However, if the goiter grows, it can cause local discomfort, for example, a feeling of pressure or tightness in the throat area or clearing of the throat. If the enlarged thyroid presses on the esophagus, swallowing problems may occur. If it compresses the trachea, this can cause breathing difficulties. Breathing as well as the cardiovascular system can be affected if the goiter grows behind the breastbone (retrosternal goiter).
Goiter: When do you need to see a doctor?
Goiter: diagnosis and therapy
First, the doctor will perform various examinations to determine whether it is indeed a goiter and what has caused it. He will then initiate appropriate therapy.
Diagnosis
An enlarged goiter can often be seen with the naked eye; a slightly enlarged thyroid gland can sometimes be felt on the neck. However, an ultrasound examination (sonography) of the thyroid gland is much more precise – this is why it is the method of choice for diagnosing goiter. Ultrasound can be used to determine the exact size of the thyroid gland. In addition, the physician can often already recognize whether it is a struma nodosa or struma diffusa.
Beyond this basic diagnosis, there are other examination methods to further determine goiter:
- Measurement of free T3 and T4 or calcitonin in the blood.
- Scintigraphy of the thyroid gland: This nuclear medical examination makes it possible to distinguish cold nodules from warm/hot nodules in the case of goiter nodosa. This is important because cold nodules may also be thyroid cancer.
- Tissue sampling using a hollow needle (fine needle biopsy): It is usually performed when a malignant tissue change is suspected in the thyroid gland. A small piece of tissue is removed from the suspected area and examined microscopically. In this way, altered cells can be detected.
- Chest X-ray (chest X-ray): This allows the exact location of a goiter to be determined in more detail.
Once the cause and hormone status of the enlarged thyroid are known, the physician initiates appropriate therapy.
Therapy
Drug therapy
First, in the case of euthyroid goiter, iodide is given in tablet form to restore sufficient iodine to the thyroid gland. In this way, its volume can often be reduced by 30 to 40 percent. If iodine treatment alone does not bring satisfactory results after six to twelve months, additional administration of L-thyroxine (a form of T4) is started. This mainly lowers the TSH level and contributes to the reduction of the goiter.
In the case of a hyperthyroid goiter (with increased T3 and T4 production) or autonomous nodules, iodine substitution is out of the question because otherwise a hyperthyroid crisis can occur. This is an acute, life-threatening metabolic derailment caused by sudden release of thyroid hormones. Especially in older patients, the level of hormone production in a goiter must be precisely determined, as autonomous nodules are often present.
Operation
If a malignant tumor is the cause of goiter, the entire thyroid gland must be removed. Those affected must then take the vital hormones T3 and T4 for the rest of their lives.
Radioiodine therapy
Nuclear medical radioiodine therapy is an alternative if, for example, there is an increased risk of surgery or the goiter keeps recurring after drug treatment. In this treatment method, the patient is administered a radioactive iodine isotope, which accumulates in the thyroid gland. There it partially damages the tissue, reducing the volume of the thyroid gland by up to 50 percent.
Other forms of goiter are treated according to cause:
Hashimoto’s thyroiditis is treatable, but currently not curable. Once a relevant proportion of the tissue of the endocrine gland has been destroyed, the patient receives the missing thyroid hormones as medication.
Malignant tumors of the thyroid gland require complete removal (resection); radioiodine therapy may also be used for benign tumors.
In the case of peripheral hormone resistance, high doses of L-thyroxine may need to be treated.
Goiter: What you can do yourself
Everyone can help to ensure that a possible goiter is detected at an early stage or does not develop in the first place:
Have regular check-ups: Older people in particular should have regular examinations by a doctor in order to detect the onset of goiter as early as possible. Anyone who suddenly has difficulty swallowing or a lumpy feeling in the throat should also consult a family doctor.
Pay attention to diet: For the prevention and treatment of iodine deficiency goiter, an iodine-rich diet is recommended. However, most plant foods as well as meat and dairy products from iodine-deficient regions (such as Germany) contain hardly any iodine. Therefore, foods are often fortified with iodine. Experts also recommend the use of iodized salt (iodized table salt).
By the way, seafood has a relatively high iodine content. Eating pollock, herring or mackerel can therefore help prevent goiter.
