What is Goiter?
Goiter is an enlargement of the thyroid gland and the size of goiter can vary. Causes of goiter mainly revolve around the thyroid gland, but also include systemic problems and certain risk factors. Symptoms of goiter are mostly common, but may vary from person to person, while some may not experience any symptoms at all. Some types of goiter have also been identified and diagnosis of goiter is important to plan proper treatment options.
Goiter can be a result of several conditions, including those related to the thyroid gland and thyroid hormones. It is important to understand the thyroid gland, its hormones and its functions to be able to manage goiter in a better way.
Thyroid Gland and Goiter
The thyroid gland is an important endocrine gland located in the lower part in the front of the neck. The main function of the thyroid gland is to produce thyroid hormones, which are responsible for maintaining body temperature, metabolism and effective functioning of body parts. The thyroid gland produces triiodothyronine (T3) and thyroxine (T4), which are known as the thyroid hormones. The production of these hormones is mainly controlled by the Thyroid Stimulating Hormone (TSH), which is secreted by the pituitary gland located at the base of the brain.
Enlargement of thyroid gland or goiter can occur due to various causes and can affect the body functions. Goiter can occur either due to over production of thyroid hormones or even due to underproduction. However, sometimes enlargement of thyroid gland or goiter can be present with normal levels of thyroid hormones as well.
Types of Goiter
Some types of goiter are
- Smooth Diffuse Goiter – In this type of goiter, the enlarged thyroid gland is larger than usual size, with swelling of the entire gland and the appearance is smooth and uniform, but not lumpy. There are various causes of diffuse smooth goiter, most of which are the common causes of goiter usually considered. These range from iodine deficiency, underactive or overactive thyroid, thyroiditis, Grave's disease, hereditary factors, other medical conditions or medications that affect the thyroid gland.
- Nodular Goiter – In this type of goiter, small lumps or nodules develop in the thyroid gland and the gland is enlarged with a lumpy appearance. It may be a single lump or nodule or may be multinodular goiter with many lumps or nodules. The causes of nodular goiter are not clear but usually involve some kind of growth in the thyroid gland, ranging from cyst or tumor to cancer.
Causes of Goiter
Goiter can be a result of various conditions. Some of the common causes of goiter include
Deficiency of Iodine
Iodine deficiency has been the commonest cause of goiter. Iodine is required for adequate production of thyroid hormones, which when found to be inadequate, can cause reduced production of thyroid hormones. This is hypothyroidism, due to reduced hormone production. The enlargement of thyroid gland or goiter results as the gland tries to obtain more iodine to be able to produce sufficient amount of thyroid hormones.
Iodine deficiency still remains a common cause of goiter and a matter of concern in developing areas. Many developed nations have worked towards improving this status by adding iodine to salt and other fortified foods, with a view to prevent goiter.
This is a form of thyroid problem and a cause of goiter, where there is overproduction of thyroid hormones. This is hyperthyroidism, which too causes goiter. In this case, the body reacts to the increased levels of thyroid hormones and attacks the thyroid gland, causing it to swell, which results in goiter.
Thyroiditis is an inflammation of the thyroid gland, which can cause swelling of the thyroid gland. This too affects the normal production of thyroid hormones and is a common cause of goiter.
This is an autoimmune condition and another common cause of goiter. Being autoimmune in nature, in Hashimoto's Thyroiditis, a person's immune system attacks the thyroid gland causing destruction. This makes the gland unable to produce adequate thyroid hormones, which is counter reacted by increase in TSH hormone, to stimulate the thyroid gland. This results in enlargement of the thyroid gland and causes goiter.
During pregnancy, production of a hormone called human chorionic gonadotropin (HCG), can sometimes result in slight enlargement of the thyroid gland and cause goiter.
Development of a single nodule in the thyroid gland can cause goiter, in which case a lump can be noted in the enlarged thyroid gland. Multinodular goiter is also one of the causes of goiter, in which multiple nodules or lumps are formed in the thyroid gland, causing enlargement or goiter. The nodules in nodular goiter can be formed due to fluid filled cysts, benign growths or tumors in the thyroid gland and are the causes of goiter.
While thyroid cancer is considered to be rare, it can cause goiter due to growth and enlargement of the thyroid gland.
Certain conditions are known to increase the risk of goiter in some cases. These include people consuming less iodine or those residing in areas known to have a shortage of iodine, aging population and women in general. People who have experienced in the past or have a family history of thyroid problems or any other autoimmune disorders are also at an increased risk of goiter. Exposure to radiations or certain medications may also increase the risk of goiter. Some women may be at an increased risk of goiter during their pregnancy or menopause.
Symptoms of Goiter
Symptoms of goiter may vary as some may feel enlargement of the thyroid gland and related symptoms, while some may not feel any symptoms at all. The enlargement of thyroid gland may be noticed as a swelling in the front part of the neck. The size of the swelling may vary and sometimes be very minimally noticeable.
Goiter or enlarged thyroid gland is usually painless, but sometimes, infection or inflammation can cause pain in the swollen region. Goiter can lead to feeling of tightness or heaviness in the throat region. Some people having goiter also show changes in their voice, high-pitched voice or sometimes hoarseness of voice is a frequent symptom of goiter. Coughing may also be seen in some, as a symptom of goiter.
Enlarged thyroid gland or goiter can exert pressure over the surrounding structures, which can result in some symptoms. Pressure over the windpipe can cause difficulty in breathing, while pressure over the food pipe can cause difficulty in swallowing or painful swallowing. In severe cases, painful swallowing can sometimes result in reduced appetite.
Diagnosis of Goiter
Clinical examination and history of a person helps to reveal possible conditions related to goiter. A noticeable or palpable swelling in the front neck region may need to be evaluated properly. Minimally swollen thyroid must be examined carefully to understand the possibility of goiter.
Investigations for diagnosis of goiter usually include bloods tests or thyroid function tests to determine the thyroid hormone levels. Tests to check T3, T4 and TSH levels are commonly ordered. Thyroid function tests help to determine the functioning of the thyroid gland and aid in diagnosis of goiter. In addition bloods tests, may be done to detect the presence of infection, inflammation or autoimmune disorders.
Ultrasonography of the thyroid gland often helps to detect an enlarged thyroid and diagnose goiter. It also helps to understand the type of goiter and help to reveal the nature of nodules in case of nodular goiter. Radioactive thyroid scans may be considered in some cases to diagnose goiter, if relevant causes are suspected.
Tissue biopsy may be considered in some cases, particularly in nodular goiter, during which a small piece of tissue is taken from the enlarged thyroid. This is studied for the nature of cells present, which can help to diagnose goiter and find the exact cause of goiter, based on which treatment can be planned.
Scans like CT scan, MRI may be advised to determine any abnormality in the thyroid gland or to rule out other medical conditions.
Treatment of Goiter
Treatment of goiter mainly depends on the cause, which varies from person to person. If goiter is a result of some underlying medical condition, it is important to treat that condition first. For small goiter, which does not produce any symptoms or is harmless, no medication may be given. However, regular follow-ups may be advised to note any changes that would require treatment of goiter.
In case of goiter, in which the thyroid hormone levels are either low or high may requirement treatment to adjust the hormone levels. This can help to keep goiter or thyroid enlargement and symptoms of goiter under control. For goiter due to iodine deficiency, usually iodine replacement is given.
Thyroidectomy - For some cases of goiter, surgical treatment options (thyroidectomy) may be considered as appropriate. Surgery for goiter depends on the cause and severity of the condition. Surgical treatment may involve removing a part or entire thyroid gland in some severe cases. Thyroidectomy may have risk of some complications like damage to a nerve or to the parathyroid gland. It is advisable to seek medical opinion and discuss the best possible treatment options for goiter.
In case of thyroid cancer, surgical treatment for thyroid cancer is considered. Additional treatment for thyroid cancer may be required, depending on the severity and stage of cancer.
Radioactive Iodine - Another treatment option for goiter related to an overactive thyroid includes treatment with radioactive iodine. The medication may be given through a drink or a capsule, which is taken orally. It reaches the thyroid gland and destroys thyroid cells, which are responsible for overproduction of hormones. However, there are chances that this treatment may result in underproduction of thyroid hormones, which needs to be managed with oral medications.
With different types of goiter and various treatment options for goiter, it is important to seek timely medical advice and follow it religiously. Adequate iodine intake is essential for all, particularly in case of pregnant or lactating women and children.