The thyroid is a small gland located at the base of the neck, in the front. The thyroid controls many functions of the organism through the production of thyroid hormones: thyroxine (T4) and triiodiothyronine (T3). The production of thyroid hormones is, in turn, controlled by the thyroid stimulating hormone (TSH) secreted by the pituitary gland, a gland located inside the skull. Thyroid hormones regulate important body functions, including breathing, heart rate, body temperature, central nervous system development and body growth.
Goiter refers to an increase in the volume of the thyroid gland. The size of a goiter can vary from person to person. In most cases, the goiter is small and does not cause any symptoms, but if the thyroid volume increases significantly, breathing and swallowing disturbances may occur.
There are two main types of goiter:
- diffuse goiter: The entire thyroid is enlarged and its surface is smooth to palpation
- nodular goiter: solid or fluid-filled nodules develop inside the thyroid, making the surface uneven on palpation
Not all types of goiter cause ailments (symptoms). Initially, therefore, it can be difficult to notice that you have it. The main symptom of goiter is a visible swelling at the base of the neck, which can be seen in the mirror when shaving or putting on make-up. The swelling also moves up and down when you swallow.
Other symptoms may be: coughing, a tight throat feeling, and changes in the voice, such as hoarseness.
Less commonly, you may also have difficulty swallowing and breathing.
The main causes of the appearance of goiter can be:
- low iodine diet: iodine is mainly present in milk and fish and its adequate consumption guarantees the correct function of the thyroid gland. If iodine is not taken in sufficient quantities, the thyroid becomes underactive and increases in size to produce more thyroid hormones
- underactive thyroid (hypothyroidism): in the event that it does not produce enough hormones, the thyroid tries to compensate by increasing its volume
- overactive thyroid (hyperthyroidism): an increased production of thyroid hormones corresponds to an increase in the volume of the gland
- pregnancy and menopauseChanges in hormone levels that occur during pregnancy and menopause can affect thyroid function
- thyroiditis: processes of inflammation that develop in the thyroid gland
- nodules: single or multiple, within the thyroid
- thyroid tumors
Goiter can affect anyone but is more common in women and people over the age of 40.
Other risk factors can be:
- smoke: tobacco contains a chemical, called thiocyanate, which can interfere with the body's ability to use iodine. People who smoke and eat a low-iodine diet are therefore particularly at risk
- drugs such as immunosuppressants and lithium: lithium is often used to treat a variety of mental health conditions such as depression and bipolar disorder
- radiation exposure
When you notice a swelling of the neck it is good to go to the doctor who, by palpating the area, can detect the presence of the goiter. After the visit, further tests are done to make the diagnosis, which may include:
- blood tests, to determine the amount of hormones produced by the thyroid gland and ascertain any abnormal production of specific antibodies
- ultrasound, to measure the size of the thyroid and check for the presence of nodules
- scintigraphy, to check the structure and function of the thyroid using a small amount of radioactive (iodine or technetium) that will accumulate in the thyroid. Radioactivity at the thyroid level will therefore allow us to study the function and size of the gland using a special machine
- fine needle aspiration, to determine the nature of the goiter cells. The fine needle aspiration is performed with a fine needle, usually under the guidance of an ultrasound scan, and consists in the removal of a small amount of tissue to be subjected to histological examination
The treatment of goiter depends on the disorders (symptoms) and the causes that have determined it.
A small goiter that does not cause problems usually does not need treatment.
If the goiter is caused by hypothyroidism, synthetic thyroid hormone T4 is given; if it is caused by hyperthyroidism, radioactive iodine, anti-thyroid drugs, beta-blockers are used.
If the goiter interferes with breathing or swallowing, surgery may be required to remove part or all of the thyroid (thyroidectomy).
Higher Institute of Health (ISS). National Congenital Hypothyroid Registry (RNIC)
Higher Institute of Health (ISS). National Observatory for the Monitoring of Iodoprophylaxis in Italy (OSNAMI)
Ministry of Health. Iodine and health