Goiter means enlargement of thyroid gland. It has no information value regarding thyroid gland function. Goiter can be caused by many factors from trivial to potentially very dangerous.
First we should know more about thyroid gland. It is an organ located in the neck in front of the windpipe. Thyroid gland produces hormones thyroxine and triiodothyronine that have complex effects on human body. In children these hormones participate in development of the central nervous system, they affect energy metabolism, maintain body weight, heart rate, digestive tract functions and many others. Iodine is needed for thyroid hormones production. Thyroid gland function is regulated by certain hormones produced in our brain (in the pituitary and hypothalamus). And now let’s move to the issue of goiter.
Goiter can be divided according to thyroid gland function into three main groups:
- Goiter with normal thyroid function
- Goiter with increased thyroid function
- Goiter with reduced thyroid function
Further, enlargement of thyroid gland can be divided into focal and diffuse. Focal goiter means enlargement of one or more parts of thyroid gland, by diffuse goiter thyroid gland is enlarged as a whole.
Reduced intake of iodine in diet can be a problem. By lack of iodine thyroid hormone production is disrupted and thyroid gland reacts by enlargement, because larger gland is more able to catch more iodine molecules. Symptoms of decreased production of thyroid hormones (hypothyroidism) may be present. Treatment for this condition is quite simple – increase daily intake of iodine.
Goitrogen is a substance causing thyroid gland enlargement. Such substances are present in a lot of food, for example in cabbage. Excessive eating of such food can increase the thyroid gland. Thyroid gland function disorder is in this case usually not present. The solution is to reduce the intake of dietary goitrogens. In case the gland is too enlarged, its tissue can be solved surgically.
There are some diseases that occur because of immune reaction against thyroid gland. Most known are Graves’ disease and Hashimoto's disease. In Graves' disease thyroid antibodies cause irritation and increased secretion of thyroid hormones. Thyroid gland is enlarged disease manifests with overactive thyroid gland symptoms. Later, as the inflammation damage goes on, the condition changes into hypothyroidism. Medications are used that suppress thyroid function and sometimes the gland is surgically removed. In Hashimoto's disease, the situation is different. Antibodies openly harm the thyroid gland from the beginning and its function decreases. The disease therefore manifests with hypothyroidism. Treatment includes medication replacing missing thyroid hormones.
These are congenital rare defects of thyroid gland enzymes that are essential for hormone production. Thyroid hormone levels are low and that forces brain to stimulate thyroid gland to increased hormone production. This stimulation causes goiter development. The only treatment is to replace missing hormones with pharmaceutical preparation.
Thyroid gland tumors
Benign and malignant tumors of the thyroid gland may cause it to enlarge. It is usually not enlargement of whole thyroid gland, but only part of it – a node. Benign tumors often produce thyroid hormones and are therefore associated with its increased function. Malignant thyroid tumors usually do not produce anything and the gland works normally. Only when thyroid gland is severely damaged by tumor growth, its functions may decrease. In benign tumor surgical removal is sufficient. By cancer surgical interventions is often combined with administration of radioactive iodine to destroy eventual metastases. Many cells of malignant thyroid tumors actually retain the ability to scavenge iodine from blood and pick up also molecules of radioactive iodine that destroys them.
They can be distinguished into two groups. Some symptoms occur because of oppression of surrounding tissues by goiter mass and other symptoms are result of thyroid functional changes.
Oppression by goiter tissue manifests in later stages when the gland is more enlarged. People can complain about pain of throat, troubles with swallowing and shortness of breath. Neck nerves innervating vocal cords may be affected as well and that causes hoarseness.
As mentioned above, changes of thyroid gland function may or may not be present. All information about symptoms of hyperthyroidism and hypothyroidism can be found in relevant texts dedicated to this issue.
Enlargement of the thyroid gland can be felt, preferably during swallowing. In bigger enlargement the goiter can be seen by naked eye. When there is suspicion about thyroid gland enlargement, it is advisable to investigate any clinical signs of thyroid function changes (from medical history), provide an ultrasound examination of the gland and take a blood sample to investigate blood levels of thyroid hormones. Suspecting autoimmune disorder we can detect some autoantibodies from a blood sample. Especially when focal enlargement is present, a biopsy using fine needle may be performed and gained sample may be sent for histological examination.
Treatment shall be targeted on the specific cause responsible for the goiter formation. Treatment options usually include administering higher doses of iodine in the diet, using drugs to suppress thyroid gland functions, drugs replacing missing hormones and surgical removal of whole thyroid gland or only of its part.