What is a goiter?

A goiter¹ is an abnormal enlargement of the thyroid gland. The thyroid, a butterfly-shaped gland located at the base of the neck, produces hormones that regulate numerous body functions, including heart rate, blood pressure, body temperature, and weight.

Goiters cause a lump² in the front of the neck. This lump moves up and down when you swallow. Goiters can vary in size from person to person.

A goiter is not a disease in and of itself. Goiters are usually painless; however, a large enough goiter can cause a cough and difficulty swallowing or breathing. Large goiters may also cause changes to your voice, such as hoarseness.

The most common cause of goiter in patients worldwide is insufficient iodine in the diet. In the United States, salt is commonly iodized (iodine is added as a supplement). Because of this, goiters in the U.S. are more frequently caused by excess or insufficient thyroid hormone production and growths on the gland itself.

The treatment your healthcare provider may recommend will depend on your goiter’s size, your symptoms, and the underlying cause of your goiter. Small goiters that aren't noticeable and don't cause problems or noticeable symptoms generally don't require treatment.

Enlarged thyroid

There are two ways³ in which the thyroid might become enlarged.

One type of goiter, called a diffuse goiter, occurs when the entire thyroid gland is enlarged, often feeling smooth to the touch.

The other type, called a nodular goiter, occurs when one or more solid or fluid-filled lumps (called nodules) develop within the thyroid. This can make the thyroid feel bumpy to the touch.

In general, most thyroid nodules are benign⁴ (non-cancerous)—only 2 or 3 out of 20 are malignant (cancerous). Most thyroid nodules are cysts filled with fluid or a storm of the thyroid hormone colloid. Solid nodules with little fluid or colloid are more likely to be cancerous; however, most are benign. In some cases, thyroid nodules make too much thyroid hormone, leading to hyperthyroidism.

Changes to a thyroid’s size and shape can often be felt—or even seen—by a patient or healthcare provider. Benign thyroid nodules can sometimes be left untreated and monitored with watchful waiting, as long as they aren’t growing larger or causing any uncomfortable symptoms. Other more severe cases may require medical treatment.

If you see or feel any changes in the size or shape of your thyroid, contact your healthcare provider. He or she will be able to determine whether your condition is benign and provide you with the best course of treatment, if necessary.

What does the thyroid do?

The thyroid gland⁵ plays a major role in your body’s metabolism and growth.

This gland produces two main hormones: thyroxine (T-4) and triiodothyronine (T-3). These hormones circulate in the bloodstream and aid in the regulation of metabolic activity. They maintain the rate at which your body uses fats and carbohydrates, help control your body temperature and weight, influence your heart rate, and help regulate the production of proteins.

Your thyroid gland also produces calcitonin, a hormone that helps regulate the amount of calcium in your blood.

The hypothalamus and pituitary gland controls the rate at which T-4 and T-3 are produced and released. The hypothalamus is an area at the base of the brain that acts like a thermostat for the body. It signals the pituitary gland to make a hormone known as thyroid-stimulating hormone (TSH).

The pituitary gland, also located at the base of the brain, releases TSH. The amount released depends upon how much thyroxine and T-3 are present in your blood. Your thyroid, in turn, regulates the production of hormones based on the amount of TSH it receives from the pituitary gland.

Goiter causes

Having a goiter isn’t necessarily an indication that your thyroid gland isn't working normally. Even an enlarged thyroid may still produce normal quantities of hormones. Enlarged thyroid glands might, however, produce too much or too little thyroxine and T-3.

Enlarged thyroid causes

There are several reasons why your thyroid gland might become enlarged. Some of the most common causes of goiter are:

• Iodine deficiency: You can develop goiters if your thyroid enlarges in an effort to obtain more iodine. At the same time, getting too much iodine can also cause your thyroid gland to enlarge, particularly in people with certain risk factors⁶, such as pre-existing thyroid disease.

Iodine⁷ is a mineral found in certain foods. The body requires iodine to produce thyroid hormones.

Getting enough iodine is important for everyone, especially babies. In pregnant women, iodine deficiency can harm the fetus by causing stunted growth.

• Graves' disease: A goiter can occur when your thyroid gland produces too much thyroid hormone (hyperthyroidism). Graves’ disease⁸ is a condition in which your immune system mistakenly attacks the thyroid, causing it to make more thyroid hormone than your body needs. This overstimulation causes the thyroid to swell.

• Hashimoto's disease: A goiter can also be caused by an underactive thyroid (a condition called hypothyroidism). Hashimoto's disease is also an autoimmune disorder. However, instead of causing your thyroid to produce too much hormone, Hashimoto's damages your thyroid so that it produces too little.

When the pituitary gland senses low hormone levels, it produces more TSH to stimulate the thyroid. This overstimulation⁹ of the thyroid causes it to enlarge.

• Multinodular goiter: A multinodular goiter is characterized by the development of several solid or fluid-filled lumps called nodules on either side of the thyroid, resulting in overall enlargement of the gland. Multinodular goiter¹⁰ is thought to be the result of the genetic mutations of cells in the thyroid.

• Solitary thyroid nodules: A solitary thyroid nodule refers to the growth of a single nodule¹¹ in one part of the thyroid gland. Most solitary nodules are non-cancerous (benign) and don't lead to cancer.

• Thyroid cancer:Thyroid cancer¹² is far less common than benign thyroid nodules. A biopsy of a thyroid nodule is a very accurate tool used to determine whether a growth is cancerous.

In the United States, about 12,000 men and 35,000 women are diagnosed with thyroid cancer¹³ each year.

• Pregnancy:Human chorionic gonadotropin (HCG), a hormone produced during pregnancy, may cause your thyroid gland to enlarge slightly.
• Inflammation: Thyroiditis¹⁴ is the general term for an inflammation of the thyroid. This inflammation causes pain and swelling. This condition may also lead to the production of excess or insufficient thyroxine.

Goiter risk factors

Goiters can affect anyone. Some goiters may be present at birth, while others can develop at a later point in life.

Some factors can increase your risk of developing a goiter. Some common risk factors for goiter include:

• Insufficient dietary iodine: People who lack sufficient access to iodine and iodine supplements are at a high risk of developing goiters. Iodine deficiency may also be worsened by diets that are high in hormone-inhibiting foods, such as cabbage, broccoli, and cauliflower.
• Biological sex: Because women are more prone to thyroid disorders than men, they also have an increased risk for developing goiters.
• Age: Goiters are more common in people aged 40 and older.
• Medical history: A personal or family history of autoimmune disease increases your risk of getting a goiter.
• Pregnancy and menopause: While it is unclear exactly why, thyroid problems are more likely to occur during pregnancy and menopause.
• Certain medications: Some medications, including the heart drug amiodarone (Pacerone, others) and the psychiatric drug lithium (Lithobid, others), can increase your risk for developing a goiter.
• Radiation exposure: The risk for developing a goiter is increased by radiation treatments to the neck or chest areas and exposure to radiation (for example, from a nuclear facility, test, or accident).

Goiter symptoms

Not all goiters cause signs and symptoms. Small, mild goiters may not cause any discomfort—in fact, you may have one without even knowing it. When goiters do present signs and symptoms, they may cause¹⁵:

• Swelling at the base of the neck
• A feeling of tightness in the throat
• Coughing
• Hoarseness
• Difficult or uncomfortable swallowing or breathing

Goiter complications

Small goiters that don't cause any uncomfortable symptoms or cosmetic problems (a noticeable appearance) generally aren't a cause for concern. However, large goiters can cause discomfort and even obstruct breathing or swallowing.

When goiters are caused by conditions like hypothyroidism or hyperthyroidism, you will likely experience the symptoms of these conditions as well. This can include fatigue and weight gain, unintended weight loss, irritability, and difficulty sleeping.